diff --git a/.gitignore b/.gitignore
index 0d0456ce..a69cccd6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -19,3 +19,4 @@ node_modules
 crowdin.yml
 kotlin-js-store
 *.md
+.kotlin
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 641f0bc0..80ca15f9 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -16,14 +16,14 @@ junit = "1.2.1"
 junitJupiter = "5.10.1"
 junitVersion = "4.13.2"
 konfetti-xml = "2.0.2"
-kotlin = "2.1.10"
-ksp = "2.1.10-1.0.30"
+kotlin = "2.3.20"
+ksp = "2.3.6"
 ktlint-plugin = "11.6.1"
 ktor = "1.6.8"
 ktxCoroutine = "1.10.1"
 legacy-support = "1.0.0"
 material = "1.12.0"
-mokkery = "2.7.1"
+mokkery = "3.3.0"
 opencsv = "5.9"
 rules = "1.6.1"
 shadow = "8.1.1"
diff --git a/uhabits-android/build.gradle.kts b/uhabits-android/build.gradle.kts
index 3b868d74..201ddf7f 100644
--- a/uhabits-android/build.gradle.kts
+++ b/uhabits-android/build.gradle.kts
@@ -84,7 +84,11 @@ android {
         sourceCompatibility(JavaVersion.VERSION_17)
     }
 
-    kotlinOptions.jvmTarget = JavaVersion.VERSION_17.toString()
+    kotlin {
+        compilerOptions {
+            jvmTarget.set(org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17)
+        }
+    }
     buildFeatures.viewBinding = true
     lint.abortOnError = false
 }
diff --git a/uhabits-core/build.gradle.kts b/uhabits-core/build.gradle.kts
index 3f05a9ee..2d558e93 100644
--- a/uhabits-core/build.gradle.kts
+++ b/uhabits-core/build.gradle.kts
@@ -27,6 +27,16 @@ kotlin {
     jvm().withJava()
     jvmToolchain(17)
 
+    js(IR) {
+        browser {
+            testTask {
+                useKarma {
+                    useChromeHeadless()
+                }
+            }
+        }
+    }
+
     sourceSets {
         val commonMain by getting {
             dependencies {
@@ -66,16 +76,30 @@ kotlin {
                 implementation(libs.junit.jupiter)
             }
         }
+
+        val jsMain by getting {
+            dependencies {
+                implementation(npm("sql.js", "1.11.0"))
+                implementation(npm("sprintf-js", "1.1.3"))
+            }
+        }
+
+        val jsTest by getting {
+            dependencies {
+                implementation(kotlin("test-js"))
+            }
+        }
     }
 }
 
 mokkery {
     defaultMockMode.set(dev.mokkery.MockMode.autofill)
+    stubs.allowConcreteClassInstantiation.set(true)
 }
 
-tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile> {
+tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinJvmCompile> {
     compilerOptions {
-        freeCompilerArgs.add("-Xjvm-default=all")
+        freeCompilerArgs.add("-jvm-default=enable")
     }
 }
 
diff --git a/uhabits-core/karma.config.d/karma.conf.js b/uhabits-core/karma.config.d/karma.conf.js
new file mode 100644
index 00000000..7b5e0d2b
--- /dev/null
+++ b/uhabits-core/karma.config.d/karma.conf.js
@@ -0,0 +1,38 @@
+const path = require("path");
+const migrationsDir = path.resolve(__dirname, "../../../../uhabits-core/assets/main/migrations");
+const testAssetsDir = path.resolve(__dirname, "../../../../uhabits-core/assets/test");
+const fontsDir = path.resolve(__dirname, "../../../../uhabits-core/assets/main/fonts");
+
+config.set({
+    browserNoActivityTimeout: 120000,
+    browserDisconnectTimeout: 30000,
+    browserDisconnectTolerance: 3,
+    client: {
+        mocha: {
+            timeout: 30000
+        }
+    },
+    proxies: {
+        '/migrations/': '/absolute' + migrationsDir + '/',
+        '/test-assets/': '/absolute' + testAssetsDir + '/',
+        '/fonts/': '/absolute' + fontsDir + '/'
+    }
+});
+
+config.files.push(
+    { pattern: migrationsDir + '/*.sql', included: false, served: true, watched: false },
+    { pattern: testAssetsDir + '/**/*', included: false, served: true, watched: false },
+    { pattern: fontsDir + '/*.ttf', included: false, served: true, watched: false }
+);
+
+// Use sql-asm.js (pure JS, no WASM binary loading) to avoid karma-webpack
+// issue #498 where WASM assets in webpack's temp output dir are not served.
+config.webpack.resolve = config.webpack.resolve || {};
+config.webpack.resolve.fallback = Object.assign(
+    config.webpack.resolve.fallback || {},
+    { fs: false, path: false, crypto: false }
+);
+config.webpack.resolve.alias = Object.assign(
+    config.webpack.resolve.alias || {},
+    { "sql.js": path.resolve(__dirname, "../../node_modules/sql.js/dist/sql-asm.js") }
+);
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/platform/JvmAnnotations.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/platform/JvmAnnotations.kt
new file mode 100644
index 00000000..abd3c6b0
--- /dev/null
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/platform/JvmAnnotations.kt
@@ -0,0 +1,22 @@
+package org.isoron.platform
+
+@OptIn(ExperimentalMultiplatform::class)
+@OptionalExpectation
+@Target(
+    AnnotationTarget.FUNCTION,
+    AnnotationTarget.PROPERTY_GETTER,
+    AnnotationTarget.PROPERTY_SETTER
+)
+@Retention(AnnotationRetention.SOURCE)
+expect annotation class Synchronized()
+
+@OptIn(ExperimentalMultiplatform::class)
+@OptionalExpectation
+@Target(
+    AnnotationTarget.FUNCTION,
+    AnnotationTarget.PROPERTY,
+    AnnotationTarget.PROPERTY_GETTER,
+    AnnotationTarget.PROPERTY_SETTER
+)
+@Retention(AnnotationRetention.SOURCE)
+expect annotation class JvmStatic()
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/platform/time/Dates.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/platform/time/Dates.kt
index c39cb3ae..a77213f9 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/platform/time/Dates.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/platform/time/Dates.kt
@@ -238,6 +238,8 @@ fun getWeekdaySequence(firstWeekday: DayOfWeek): List<DayOfWeek> {
 
 expect fun getFirstWeekdayNumberAccordingToLocale(): Int
 
+expect fun computeToday(hourOffset: Int = 0, minuteOffset: Int = 0): LocalDate
+
 fun countWeekdayOccurrencesInMonth(startOfMonth: LocalDate): Array<Int> {
     val weekday = (startOfMonth.dayOfWeek.daysSinceSunday + 1) % 7
     val freq = Array(7) { 0 }
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/io/LoopDBImporter.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/io/LoopDBImporter.kt
index ff7670ef..529624f8 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/io/LoopDBImporter.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/io/LoopDBImporter.kt
@@ -77,7 +77,7 @@ class LoopDBImporter(
     override suspend fun importHabitsFromFile(file: UserFile) {
         val db = opener.open(file.pathString)
         db.migrateTo(DATABASE_VERSION) { version ->
-            val filename = "%02d.sql".format(version)
+            val filename = org.isoron.platform.io.format("%02d.sql", version)
             fileOpener.openResourceFile("migrations/$filename").lines().joinToString("\n")
         }
 
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/EntryList.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/EntryList.kt
index ee3eb48b..746474c5 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/EntryList.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/EntryList.kt
@@ -19,6 +19,7 @@
 
 package org.isoron.uhabits.core.models
 
+import org.isoron.platform.Synchronized
 import org.isoron.platform.time.DayOfWeek
 import org.isoron.platform.time.LocalDate
 import org.isoron.platform.time.TruncateField
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/HabitList.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/HabitList.kt
index 228c46a4..e56dbf87 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/HabitList.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/HabitList.kt
@@ -194,7 +194,10 @@ abstract class HabitList : Iterable<Habit> {
                 habit.color.toCsvColor(),
                 if (habit.isNumerical) habit.unit else "",
                 if (habit.isNumerical) habit.targetType.name else "",
-                if (habit.isNumerical) habit.targetValue.toString() else "",
+                if (habit.isNumerical) {
+                    val s = habit.targetValue.toString()
+                    if ('.' !in s) "$s.0" else s
+                } else "",
                 habit.isArchived.toString()
             )
             sb.append(csvLine(cols))
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/ModelObservable.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/ModelObservable.kt
index 3f846b8d..2b6da8a0 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/ModelObservable.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/ModelObservable.kt
@@ -18,6 +18,8 @@
  */
 package org.isoron.uhabits.core.models
 
+import org.isoron.platform.Synchronized
+
 /**
  * A ModelObservable allows objects to subscribe themselves to it and receive
  * notifications whenever the model is changed.
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/Score.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/Score.kt
index c8053d46..9b26f348 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/Score.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/Score.kt
@@ -18,6 +18,7 @@
  */
 package org.isoron.uhabits.core.models
 
+import org.isoron.platform.JvmStatic
 import org.isoron.platform.time.LocalDate
 import kotlin.math.pow
 import kotlin.math.sqrt
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/ScoreList.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/ScoreList.kt
index 01949896..fe30e746 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/ScoreList.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/ScoreList.kt
@@ -18,6 +18,7 @@
  */
 package org.isoron.uhabits.core.models
 
+import org.isoron.platform.Synchronized
 import org.isoron.platform.time.LocalDate
 import org.isoron.uhabits.core.models.Score.Companion.compute
 import kotlin.math.max
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/StreakList.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/StreakList.kt
index 03cd23bf..b08e4129 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/StreakList.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/StreakList.kt
@@ -18,6 +18,7 @@
  */
 package org.isoron.uhabits.core.models
 
+import org.isoron.platform.Synchronized
 import org.isoron.platform.time.LocalDate
 import kotlin.math.min
 
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/memory/MemoryHabitList.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/memory/MemoryHabitList.kt
index 180a2d4d..c12e5710 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/memory/MemoryHabitList.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/memory/MemoryHabitList.kt
@@ -18,6 +18,7 @@
  */
 package org.isoron.uhabits.core.models.memory
 
+import org.isoron.platform.Synchronized
 import org.isoron.uhabits.core.models.Habit
 import org.isoron.uhabits.core.models.HabitList
 import org.isoron.uhabits.core.models.HabitMatcher
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/sqlite/SQLiteHabitList.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/sqlite/SQLiteHabitList.kt
index 6c034b3b..2342634f 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/sqlite/SQLiteHabitList.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/models/sqlite/SQLiteHabitList.kt
@@ -19,6 +19,7 @@
 package org.isoron.uhabits.core.models.sqlite
 
 import me.tatarka.inject.annotations.Inject
+import org.isoron.platform.Synchronized
 import org.isoron.uhabits.core.database.HabitData
 import org.isoron.uhabits.core.database.HabitRepository
 import org.isoron.uhabits.core.models.Frequency
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/HabitCardListCache.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/HabitCardListCache.kt
index d627dc3f..b7ef20a7 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/HabitCardListCache.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/HabitCardListCache.kt
@@ -19,6 +19,7 @@
 package org.isoron.uhabits.core.ui.screens.habits.list
 
 import me.tatarka.inject.annotations.Inject
+import org.isoron.platform.Synchronized
 import org.isoron.platform.time.getToday
 import org.isoron.uhabits.core.AppScope
 import org.isoron.uhabits.core.commands.Command
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/ui/views/NumberButton.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/ui/views/NumberButton.kt
index 122fba73..5e181cf5 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/ui/views/NumberButton.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/ui/views/NumberButton.kt
@@ -23,25 +23,26 @@ import org.isoron.platform.gui.Canvas
 import org.isoron.platform.gui.Color
 import org.isoron.platform.gui.Font
 import org.isoron.platform.gui.View
+import org.isoron.platform.io.format
 import kotlin.math.round
 
 fun Double.toShortString(): String = when {
-    this >= 1e9 -> "%.1fG".format(this / 1e9)
-    this >= 1e8 -> "%.0fM".format(this / 1e6)
-    this >= 1e7 -> "%.1fM".format(this / 1e6)
-    this >= 1e6 -> "%.1fM".format(this / 1e6)
-    this >= 1e5 -> "%.0fk".format(this / 1e3)
-    this >= 1e4 -> "%.1fk".format(this / 1e3)
-    this >= 1e3 -> "%.1fk".format(this / 1e3)
-    this >= 1e2 -> "%.0f".format(this)
+    this >= 1e9 -> format("%.1fG", this / 1e9)
+    this >= 1e8 -> format("%.0fM", this / 1e6)
+    this >= 1e7 -> format("%.1fM", this / 1e6)
+    this >= 1e6 -> format("%.1fM", this / 1e6)
+    this >= 1e5 -> format("%.0fk", this / 1e3)
+    this >= 1e4 -> format("%.1fk", this / 1e3)
+    this >= 1e3 -> format("%.1fk", this / 1e3)
+    this >= 1e2 -> format("%.0f", this)
     this >= 1e1 -> when {
-        round(this) == this -> "%.0f".format(this)
-        else -> "%.1f".format(this)
+        round(this) == this -> format("%.0f", this)
+        else -> format("%.1f", this)
     }
     else -> when {
-        round(this) == this -> "%.0f".format(this)
-        round(this * 10) == this * 10 -> "%.1f".format(this)
-        else -> "%.2f".format(this)
+        round(this) == this -> format("%.0f", this)
+        round(this * 10) == this * 10 -> format("%.1f", this)
+        else -> format("%.2f", this)
     }
 }
 
diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/ui/views/Ring.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/ui/views/Ring.kt
index 6c1d6a51..f9756026 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/ui/views/Ring.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/uhabits/core/ui/views/Ring.kt
@@ -22,6 +22,7 @@ package org.isoron.uhabits.core.ui.views
 import org.isoron.platform.gui.Canvas
 import org.isoron.platform.gui.Color
 import org.isoron.platform.gui.View
+import org.isoron.platform.io.format
 import kotlin.math.max
 import kotlin.math.min
 
@@ -51,7 +52,7 @@ class Ring(
         if (label) {
             canvas.setColor(color)
             canvas.setFontSize(radius * 0.4)
-            canvas.drawText("%.0f%%".format(percentage * 100), width / 2, height / 2)
+            canvas.drawText(format("%.0f%%", percentage * 100), width / 2, height / 2)
         }
     }
 }
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/gui/DatesTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/gui/DatesTest.kt
index d93f059f..dbdc7985 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/gui/DatesTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/gui/DatesTest.kt
@@ -177,11 +177,11 @@ class DatesTest {
         val jan2 = LocalDate(2015, 1, 2)
         val jan1b = LocalDate(2015, 1, 1)
 
-        assert(jan1 < jan2)
-        assert(jan2 > jan1)
-        assert(jan1 <= jan1b)
-        assert(jan1 >= jan1b)
-        assert(jan1 == jan1b)
+        assertTrue(jan1 < jan2)
+        assertTrue(jan2 > jan1)
+        assertTrue(jan1 <= jan1b)
+        assertTrue(jan1 >= jan1b)
+        assertEquals(jan1, jan1b)
     }
 
     @Test
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/gui/ViewTestHelper.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/gui/ViewTestHelper.kt
index 4b6433b8..5cd8d3d9 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/gui/ViewTestHelper.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/gui/ViewTestHelper.kt
@@ -2,6 +2,7 @@ package org.isoron.platform.gui
 
 import org.isoron.platform.io.createTestCanvas
 import org.isoron.platform.io.createTestFileOpener
+import org.isoron.platform.io.ensureFontsLoaded
 import kotlin.test.fail
 
 suspend fun assertRenders(
@@ -37,6 +38,7 @@ suspend fun assertRenders(
     expectedPath: String,
     view: View
 ) {
+    ensureFontsLoaded()
     val canvas = createTestCanvas(width, height)
     view.draw(canvas)
     assertRenders(expectedPath, canvas)
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/DatabaseQueryHelpersTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/DatabaseQueryHelpersTest.kt
index e279a958..9fbf20dc 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/DatabaseQueryHelpersTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/DatabaseQueryHelpersTest.kt
@@ -1,5 +1,6 @@
 package org.isoron.platform.io
 
+import kotlinx.coroutines.test.runTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
@@ -8,7 +9,7 @@ import kotlin.test.assertTrue
 
 class DatabaseQueryHelpersTest {
     @Test
-    fun testQueryIteratesAllRows() {
+    fun testQueryIteratesAllRows() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         db.run("create table t(v int)")
         db.run("insert into t(v) values (10)")
@@ -24,7 +25,7 @@ class DatabaseQueryHelpersTest {
     }
 
     @Test
-    fun testQueryWithParameters() {
+    fun testQueryWithParameters() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         db.run("create table t(name text, age int)")
         db.run("insert into t(name, age) values ('Alice', 30)")
@@ -42,7 +43,7 @@ class DatabaseQueryHelpersTest {
     }
 
     @Test
-    fun testQueryWithNoResults() {
+    fun testQueryWithNoResults() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         db.run("create table t(v int)")
 
@@ -53,7 +54,7 @@ class DatabaseQueryHelpersTest {
     }
 
     @Test
-    fun testQuerySingleReturnsFirstRow() {
+    fun testQuerySingleReturnsFirstRow() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         db.run("create table t(v int)")
         db.run("insert into t(v) values (42)")
@@ -65,7 +66,7 @@ class DatabaseQueryHelpersTest {
     }
 
     @Test
-    fun testQuerySingleReturnsNullForEmptyResult() {
+    fun testQuerySingleReturnsNullForEmptyResult() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         db.run("create table t(v int)")
 
@@ -75,7 +76,7 @@ class DatabaseQueryHelpersTest {
     }
 
     @Test
-    fun testQuerySingleWithParameters() {
+    fun testQuerySingleWithParameters() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         db.run("create table t(name text, score int)")
         db.run("insert into t(name, score) values ('Alice', 90)")
@@ -96,7 +97,7 @@ class DatabaseQueryHelpersTest {
     }
 
     @Test
-    fun testNestedQueries() {
+    fun testNestedQueries() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         db.run("create table parents(id int, name text)")
         db.run("create table children(parent_id int, name text)")
@@ -126,7 +127,7 @@ class DatabaseQueryHelpersTest {
     }
 
     @Test
-    fun testQueryHandlesNullableColumns() {
+    fun testQueryHandlesNullableColumns() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         db.run("create table t(a int, b text)")
         db.run("insert into t(a, b) values (1, 'hello')")
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/DatabaseTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/DatabaseTest.kt
index 465ae62b..f6b60732 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/DatabaseTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/DatabaseTest.kt
@@ -1,5 +1,6 @@
 package org.isoron.platform.io
 
+import kotlinx.coroutines.test.runTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertNull
@@ -7,7 +8,7 @@ import kotlin.test.assertTrue
 
 class DatabaseTest {
     @Test
-    fun testVersionReadWrite() {
+    fun testVersionReadWrite() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         db.setVersion(0)
         assertEquals(0, db.getVersion())
@@ -17,7 +18,7 @@ class DatabaseTest {
     }
 
     @Test
-    fun testCreateInsertQuery() {
+    fun testCreateInsertQuery() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
 
         db.run("drop table if exists demo")
@@ -41,7 +42,7 @@ class DatabaseTest {
     }
 
     @Test
-    fun testNullHandling() {
+    fun testNullHandling() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
 
         db.run("create table nullable_demo(a int, b text, c real)")
@@ -63,7 +64,7 @@ class DatabaseTest {
     }
 
     @Test
-    fun testStatementReset() {
+    fun testStatementReset() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
 
         db.run("create table reset_demo(v int)")
@@ -95,7 +96,7 @@ class DatabaseTest {
     }
 
     @Test
-    fun testRunExtensionFunction() {
+    fun testRunExtensionFunction() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         db.run("create table ext_demo(v int)")
         db.run("insert into ext_demo(v) values (?)") { bindInt(1, 99) }
@@ -104,7 +105,7 @@ class DatabaseTest {
     }
 
     @Test
-    fun testLastInsertRowId() {
+    fun testLastInsertRowId() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         db.run("create table rowid_demo(id integer primary key autoincrement, v text)")
         db.run("insert into rowid_demo(v) values ('first')")
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/MigrationTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/MigrationTest.kt
index d5395188..97f03277 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/MigrationTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/MigrationTest.kt
@@ -6,7 +6,7 @@ import kotlin.test.assertEquals
 
 class MigrationTest {
     @Test
-    fun testMigrateFromScratch() {
+    fun testMigrateFromScratch() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         assertEquals(25, db.getVersion())
 
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/TestDatabaseHelper.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/TestDatabaseHelper.kt
index 73d0368d..f0d6c853 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/TestDatabaseHelper.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/TestDatabaseHelper.kt
@@ -1,6 +1,6 @@
 package org.isoron.platform.io
 
 expect object TestDatabaseHelper {
-    fun createEmptyDatabase(): Database
-    fun loadMigrationSQL(version: Int): String
+    suspend fun createEmptyDatabase(): Database
+    suspend fun loadMigrationSQL(version: Int): String
 }
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/TestPlatformHelper.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/TestPlatformHelper.kt
index 36f1ffde..2e5c436b 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/TestPlatformHelper.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/TestPlatformHelper.kt
@@ -5,5 +5,7 @@ import org.isoron.platform.time.LocalDateFormatter
 
 expect fun createTestFileOpener(): FileOpener
 expect fun createTestDatabaseOpener(): DatabaseOpener
+expect suspend fun createTestDatabaseOpenerSuspend(): DatabaseOpener
 expect fun createTestCanvas(width: Int, height: Int): Canvas
 expect fun createTestDateFormatter(): LocalDateFormatter
+expect suspend fun ensureFontsLoaded()
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/BaseUnitTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/BaseUnitTest.kt
index e14e224e..8951ada1 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/BaseUnitTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/BaseUnitTest.kt
@@ -23,9 +23,8 @@ import org.isoron.platform.io.DatabaseOpener
 import org.isoron.platform.io.FileOpener
 import org.isoron.platform.io.TestDatabaseHelper
 import org.isoron.platform.io.UserFile
-import org.isoron.platform.io.createTestDatabaseOpener
+import org.isoron.platform.io.createTestDatabaseOpenerSuspend
 import org.isoron.platform.io.createTestFileOpener
-import org.isoron.platform.runSuspend
 import org.isoron.platform.time.LocalDate
 import org.isoron.platform.time.setToday
 import org.isoron.uhabits.core.commands.CommandRunner
@@ -43,7 +42,13 @@ open class BaseUnitTest {
     protected lateinit var taskRunner: SingleThreadTaskRunner
     protected open lateinit var commandRunner: CommandRunner
     protected val fileOpener: FileOpener = createTestFileOpener()
-    protected val databaseOpener: DatabaseOpener = createTestDatabaseOpener()
+    private var _databaseOpener: DatabaseOpener? = null
+    protected suspend fun databaseOpener(): DatabaseOpener {
+        if (_databaseOpener == null) {
+            _databaseOpener = createTestDatabaseOpenerSuspend()
+        }
+        return _databaseOpener!!
+    }
 
     @BeforeTest
     open fun setUp() {
@@ -56,28 +61,28 @@ open class BaseUnitTest {
         commandRunner = CommandRunner(taskRunner)
     }
 
-    protected fun createTempDir(): UserFile = runSuspend {
+    protected suspend fun createTempDir(): UserFile {
         val dir = fileOpener.openUserFile("test-temp-dir-${tempFileCounter++}")
         dir.mkdirs()
-        dir
+        return dir
     }
 
-    protected fun copyResourceToTempFile(resourcePath: String): UserFile = runSuspend {
+    protected suspend fun copyResourceToTempFile(resourcePath: String): UserFile {
         val cleanPath = resourcePath.removePrefix("/")
         val tempFile = fileOpener.openUserFile("test-temp-${tempFileCounter++}")
         fileOpener.openResourceFile(cleanPath).copyTo(tempFile)
-        tempFile
+        return tempFile
     }
 
-    protected fun openDatabaseResource(resourcePath: String): Database = runSuspend {
+    protected suspend fun openDatabaseResource(resourcePath: String): Database {
         val tempFile = copyResourceToTempFile(resourcePath)
-        databaseOpener.open(tempFile.pathString)
+        return databaseOpener().open(tempFile.pathString)
     }
 
     companion object {
         private var tempFileCounter = 0
 
-        fun buildMemoryDatabase(): Database {
+        suspend fun buildMemoryDatabase(): Database {
             return TestDatabaseHelper.createEmptyDatabase()
         }
     }
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/EntryRepositoryTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/EntryRepositoryTest.kt
index 47e3ac4d..8043b863 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/EntryRepositoryTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/EntryRepositoryTest.kt
@@ -1,5 +1,6 @@
 package org.isoron.uhabits.core.database
 
+import kotlinx.coroutines.test.runTest
 import org.isoron.platform.io.TestDatabaseHelper
 import org.isoron.platform.io.queryLong
 import org.isoron.platform.io.run
@@ -19,7 +20,7 @@ class EntryRepositoryTest {
     }
 
     @Test
-    fun testInsertAndFindAll() {
+    fun testInsertAndFindAll() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         val repo = EntryRepository(db)
         val habitId = insertTestHabit(db)
@@ -44,7 +45,7 @@ class EntryRepositoryTest {
     }
 
     @Test
-    fun testDeleteByHabitIdAndTimestamp() {
+    fun testDeleteByHabitIdAndTimestamp() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         val repo = EntryRepository(db)
         val habitId = insertTestHabit(db)
@@ -62,7 +63,7 @@ class EntryRepositoryTest {
     }
 
     @Test
-    fun testDeleteByHabitId() {
+    fun testDeleteByHabitId() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         val repo = EntryRepository(db)
         val habitA = insertTestHabit(db)
@@ -80,7 +81,7 @@ class EntryRepositoryTest {
     }
 
     @Test
-    fun testIsolationBetweenHabits() {
+    fun testIsolationBetweenHabits() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         val repo = EntryRepository(db)
         val habitA = insertTestHabit(db)
@@ -97,7 +98,7 @@ class EntryRepositoryTest {
     }
 
     @Test
-    fun testAllFieldsSurviveRoundTrip() {
+    fun testAllFieldsSurviveRoundTrip() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         val repo = EntryRepository(db)
 
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/HabitRepositoryTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/HabitRepositoryTest.kt
index 7136c4d8..b36ef890 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/HabitRepositoryTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/HabitRepositoryTest.kt
@@ -1,5 +1,6 @@
 package org.isoron.uhabits.core.database
 
+import kotlinx.coroutines.test.runTest
 import org.isoron.platform.io.TestDatabaseHelper
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -9,7 +10,7 @@ import kotlin.test.assertTrue
 
 class HabitRepositoryTest {
     @Test
-    fun testInsertAndFindAll() {
+    fun testInsertAndFindAll() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         val repo = HabitRepository(db)
 
@@ -44,7 +45,7 @@ class HabitRepositoryTest {
     }
 
     @Test
-    fun testUpdate() {
+    fun testUpdate() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         val repo = HabitRepository(db)
 
@@ -65,7 +66,7 @@ class HabitRepositoryTest {
     }
 
     @Test
-    fun testDelete() {
+    fun testDelete() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         val repo = HabitRepository(db)
 
@@ -84,7 +85,7 @@ class HabitRepositoryTest {
     }
 
     @Test
-    fun testNullableFields() {
+    fun testNullableFields() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         val repo = HabitRepository(db)
 
@@ -117,7 +118,7 @@ class HabitRepositoryTest {
     }
 
     @Test
-    fun testFindAllOrderedByPosition() {
+    fun testFindAllOrderedByPosition() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         val repo = HabitRepository(db)
 
@@ -134,7 +135,7 @@ class HabitRepositoryTest {
     }
 
     @Test
-    fun testExecSQL() {
+    fun testExecSQL() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         val repo = HabitRepository(db)
 
@@ -153,7 +154,7 @@ class HabitRepositoryTest {
     }
 
     @Test
-    fun testAllFieldsSurviveRoundTrip() {
+    fun testAllFieldsSurviveRoundTrip() = runTest {
         val db = TestDatabaseHelper.createEmptyDatabase()
         val repo = HabitRepository(db)
 
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/migrations/Version22Test.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/migrations/Version22Test.kt
index 9cff1ecf..8a428553 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/migrations/Version22Test.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/migrations/Version22Test.kt
@@ -18,11 +18,12 @@
  */
 package org.isoron.uhabits.core.database.migrations
 
+import kotlinx.coroutines.test.runTest
 import org.isoron.platform.io.Database
+import org.isoron.platform.io.format
 import org.isoron.platform.io.migrateTo
 import org.isoron.platform.io.querySingle
 import org.isoron.platform.io.run
-import org.isoron.platform.runSuspend
 import org.isoron.uhabits.core.BaseUnitTest
 import kotlin.test.Test
 import kotlin.test.assertContains
@@ -32,20 +33,24 @@ import kotlin.test.assertFailsWith
 class Version22Test : BaseUnitTest() {
     private lateinit var db: Database
 
-    override fun setUp() {
-        super.setUp()
+    private suspend fun initDb() {
         db = openDatabaseResource("/databases/021.db")
     }
 
-    private fun migrateTo(version: Int) = runSuspend {
+    private suspend fun migrateTo(version: Int) {
         db.migrateTo(version) { v ->
-            val path = "migrations/%02d.sql".format(v)
+            val path = "migrations/${format("%02d.sql", v)}"
             fileOpener.openResourceFile(path).lines().joinToString("\n")
         }
     }
 
+    private fun dbTest(block: suspend () -> Unit) = runTest {
+        initDb()
+        block()
+    }
+
     @Test
-    fun testKeepValidReps() {
+    fun testKeepValidReps() = dbTest {
         val before = db.querySingle("select count(*) from repetitions") { it.getInt(0) }
         assertEquals(3, before)
         migrateTo(22)
@@ -54,7 +59,7 @@ class Version22Test : BaseUnitTest() {
     }
 
     @Test
-    fun testRemoveRepsWithInvalidId() {
+    fun testRemoveRepsWithInvalidId() = dbTest {
         db.run("insert into Repetitions(habit, timestamp, value) values (99999, 100, 2)")
         val before = db.querySingle(
             "select count(*) from repetitions where habit = 99999"
@@ -68,16 +73,16 @@ class Version22Test : BaseUnitTest() {
     }
 
     @Test
-    fun testDisallowNewRepsWithInvalidRef() {
+    fun testDisallowNewRepsWithInvalidRef() = dbTest {
         migrateTo(22)
-        val exception = assertFailsWith<Exception> {
+        val exception = assertFailsWith<Throwable> {
             db.run("insert into Repetitions(habit, timestamp, value) values (99999, 100, 2)")
         }
         assertContains(exception.message!!, "constraint")
     }
 
     @Test
-    fun testRemoveRepetitionsWithNullTimestamp() {
+    fun testRemoveRepetitionsWithNullTimestamp() = dbTest {
         db.run("insert into repetitions(habit, value) values (0, 2)")
         val before = db.querySingle(
             "select count(*) from repetitions where timestamp is null"
@@ -91,16 +96,16 @@ class Version22Test : BaseUnitTest() {
     }
 
     @Test
-    fun testDisallowNullTimestamp() {
+    fun testDisallowNullTimestamp() = dbTest {
         migrateTo(22)
-        val exception = assertFailsWith<Exception> {
+        val exception = assertFailsWith<Throwable> {
             db.run("insert into Repetitions(habit, value) values (0, 2)")
         }
         assertContains(exception.message!!, "constraint")
     }
 
     @Test
-    fun testRemoveRepetitionsWithNullHabit() {
+    fun testRemoveRepetitionsWithNullHabit() = dbTest {
         db.run("insert into repetitions(timestamp, value) values (0, 2)")
         val before = db.querySingle(
             "select count(*) from repetitions where habit is null"
@@ -114,16 +119,16 @@ class Version22Test : BaseUnitTest() {
     }
 
     @Test
-    fun testDisallowNullHabit() {
+    fun testDisallowNullHabit() = dbTest {
         migrateTo(22)
-        val exception = assertFailsWith<Exception> {
+        val exception = assertFailsWith<Throwable> {
             db.run("insert into Repetitions(timestamp, value) values (5, 2)")
         }
         assertContains(exception.message!!, "constraint")
     }
 
     @Test
-    fun testRemoveDuplicateRepetitions() {
+    fun testRemoveDuplicateRepetitions() = dbTest {
         db.run("insert into repetitions(habit, timestamp, value)values (0, 100, 2)")
         db.run("insert into repetitions(habit, timestamp, value)values (0, 100, 5)")
         db.run("insert into repetitions(habit, timestamp, value)values (0, 100, 10)")
@@ -139,10 +144,10 @@ class Version22Test : BaseUnitTest() {
     }
 
     @Test
-    fun testDisallowNewDuplicateTimestamps() {
+    fun testDisallowNewDuplicateTimestamps() = dbTest {
         migrateTo(22)
         db.run("insert into repetitions(habit, timestamp, value)values (0, 100, 2)")
-        val exception = assertFailsWith<Exception> {
+        val exception = assertFailsWith<Throwable> {
             db.run("insert into repetitions(habit, timestamp, value)values (0, 100, 5)")
         }
         assertContains(exception.message!!, "constraint")
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/migrations/Version23Test.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/migrations/Version23Test.kt
index 24fa0ffb..c0a18dfc 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/migrations/Version23Test.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/database/migrations/Version23Test.kt
@@ -19,10 +19,11 @@
 
 package org.isoron.uhabits.core.database.migrations
 
+import kotlinx.coroutines.test.runTest
 import org.isoron.platform.io.Database
+import org.isoron.platform.io.format
 import org.isoron.platform.io.migrateTo
 import org.isoron.platform.io.query
-import org.isoron.platform.runSuspend
 import org.isoron.uhabits.core.BaseUnitTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -31,26 +32,30 @@ class Version23Test : BaseUnitTest() {
 
     private lateinit var db: Database
 
-    override fun setUp() {
-        super.setUp()
+    private suspend fun initDb() {
         db = openDatabaseResource("/databases/022.db")
     }
 
-    private fun migrateTo(version: Int) = runSuspend {
+    private suspend fun migrateTo(version: Int) {
         db.migrateTo(version) { v ->
-            val path = "migrations/%02d.sql".format(v)
+            val path = "migrations/${format("%02d.sql", v)}"
             fileOpener.openResourceFile(path).lines().joinToString("\n")
         }
     }
 
+    private fun dbTest(block: suspend () -> Unit) = runTest {
+        initDb()
+        block()
+    }
+
     @Test
-    fun testMigrateTo23CreatesQuestionColumn() {
+    fun testMigrateTo23CreatesQuestionColumn() = dbTest {
         migrateTo(23)
         db.query("select question from Habits") {}
     }
 
     @Test
-    fun testMigrateTo23MovesDescriptionToQuestionColumn() {
+    fun testMigrateTo23MovesDescriptionToQuestionColumn() = dbTest {
         val descriptions = mutableListOf<String?>()
         db.query("select description from Habits") { stmt ->
             descriptions.add(stmt.getTextOrNull(0))
@@ -69,7 +74,7 @@ class Version23Test : BaseUnitTest() {
     }
 
     @Test
-    fun testMigrateTo23SetsDescriptionToNull() {
+    fun testMigrateTo23SetsDescriptionToNull() = dbTest {
         migrateTo(23)
         db.query("select description from Habits") { stmt ->
             assertEquals("", stmt.getTextOrNull(0))
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/io/HabitsCSVExporterTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/io/HabitsCSVExporterTest.kt
index ac899873..a9b5ed1d 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/io/HabitsCSVExporterTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/io/HabitsCSVExporterTest.kt
@@ -22,6 +22,7 @@ import kotlinx.coroutines.test.runTest
 import org.isoron.platform.io.ZipReader
 import org.isoron.uhabits.core.BaseUnitTest
 import org.isoron.uhabits.core.models.Habit
+import kotlin.test.BeforeTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertNotNull
@@ -29,6 +30,7 @@ import kotlin.test.assertTrue
 
 class HabitsCSVExporterTest : BaseUnitTest() {
 
+    @BeforeTest
     override fun setUp() {
         super.setUp()
         habitList.add(fixtures.createShortHabit())
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/io/ImportTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/io/ImportTest.kt
index b2b69b68..76d3b38d 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/io/ImportTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/io/ImportTest.kt
@@ -18,7 +18,7 @@
  */
 package org.isoron.uhabits.core.io
 
-import org.isoron.platform.runSuspend
+import kotlinx.coroutines.test.runTest
 import org.isoron.platform.time.LocalDate
 import org.isoron.uhabits.core.BaseUnitTest
 import org.isoron.uhabits.core.models.Entry
@@ -33,7 +33,7 @@ import kotlin.test.assertTrue
 class ImportTest : BaseUnitTest() {
 
     @Test
-    fun testHabitBullCSV() {
+    fun testHabitBullCSV() = runTest {
         importFromFile("habitbull.csv")
         assertEquals(4, habitList.size())
         val habit = habitList.getByPosition(0)
@@ -47,7 +47,7 @@ class ImportTest : BaseUnitTest() {
     }
 
     @Test
-    fun testHabitBullCSV2() {
+    fun testHabitBullCSV2() = runTest {
         importFromFile("habitbull2.csv")
         assertEquals(6, habitList.size())
         val habit = habitList.getByPosition(2)
@@ -62,7 +62,7 @@ class ImportTest : BaseUnitTest() {
     }
 
     @Test
-    fun testHabitBullCSV3() {
+    fun testHabitBullCSV3() = runTest {
         importFromFile("habitbull3.csv")
         assertEquals(2, habitList.size())
 
@@ -85,7 +85,7 @@ class ImportTest : BaseUnitTest() {
     }
 
     @Test
-    fun testHabitBullCSV4() {
+    fun testHabitBullCSV4() = runTest {
         importFromFile("habitbull4.csv")
         assertEquals(1, habitList.size())
 
@@ -99,7 +99,7 @@ class ImportTest : BaseUnitTest() {
     }
 
     @Test
-    fun testLoopDB() {
+    fun testLoopDB() = runTest {
         importFromFile("loop.db")
         assertEquals(9, habitList.size())
         val habit = habitList.getByPosition(0)
@@ -111,7 +111,7 @@ class ImportTest : BaseUnitTest() {
     }
 
     @Test
-    fun testRewireDB() {
+    fun testRewireDB() = runTest {
         importFromFile("rewire.db")
         assertEquals(3, habitList.size())
         var habit = habitList.getByPosition(1)
@@ -134,7 +134,7 @@ class ImportTest : BaseUnitTest() {
     }
 
     @Test
-    fun testTickmateDB() {
+    fun testTickmateDB() = runTest {
         importFromFile("tickmate.db")
         assertEquals(3, habitList.size())
         val h = habitList.getByPosition(2)
@@ -157,20 +157,21 @@ class ImportTest : BaseUnitTest() {
         return h.originalEntries.get(LocalDate(year, month, day)).notes == notes
     }
 
-    private fun importFromFile(assetFilename: String) = runSuspend {
+    private suspend fun importFromFile(assetFilename: String) {
         val userFile = copyResourceToTempFile(assetFilename)
         assertTrue(userFile.exists())
+        val dbOpener = databaseOpener()
         val importer = GenericImporter(
             LoopDBImporter(
                 habitList,
                 modelFactory,
-                databaseOpener,
+                dbOpener,
                 commandRunner,
                 StandardLogging(),
                 fileOpener
             ),
-            RewireDBImporter(habitList, modelFactory, databaseOpener),
-            TickmateDBImporter(habitList, modelFactory, databaseOpener),
+            RewireDBImporter(habitList, modelFactory, dbOpener),
+            TickmateDBImporter(habitList, modelFactory, dbOpener),
             HabitBullCSVImporter(habitList, modelFactory, StandardLogging())
         )
         assertTrue(importer.canHandle(userFile))
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/HabitListTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/HabitListTest.kt
index 63feb6d6..b7d6a887 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/HabitListTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/HabitListTest.kt
@@ -19,6 +19,7 @@
 package org.isoron.uhabits.core.models
 
 import org.isoron.uhabits.core.BaseUnitTest
+import kotlin.test.BeforeTest
 import kotlin.test.Test
 import kotlin.test.assertContentEquals
 import kotlin.test.assertEquals
@@ -32,6 +33,7 @@ class HabitListTest : BaseUnitTest() {
     private lateinit var activeHabits: HabitList
     private lateinit var reminderHabits: HabitList
 
+    @BeforeTest
     override fun setUp() {
         super.setUp()
         habitsArray = ArrayList()
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/HabitTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/HabitTest.kt
index 754c044c..7cc8b422 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/HabitTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/HabitTest.kt
@@ -20,6 +20,7 @@ package org.isoron.uhabits.core.models
 
 import org.isoron.platform.time.getToday
 import org.isoron.uhabits.core.BaseUnitTest
+import kotlin.test.BeforeTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
@@ -28,6 +29,7 @@ import kotlin.test.assertTrue
 
 class HabitTest : BaseUnitTest() {
 
+    @BeforeTest
     override fun setUp() {
         super.setUp()
     }
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/StreakListTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/StreakListTest.kt
index b2006929..8953c7da 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/StreakListTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/StreakListTest.kt
@@ -21,6 +21,7 @@ package org.isoron.uhabits.core.models
 import org.isoron.platform.time.LocalDate
 import org.isoron.platform.time.getToday
 import org.isoron.uhabits.core.BaseUnitTest
+import kotlin.test.BeforeTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
@@ -29,6 +30,7 @@ class StreakListTest : BaseUnitTest() {
     private lateinit var streaks: StreakList
     private lateinit var today: LocalDate
 
+    @BeforeTest
     override fun setUp() {
         super.setUp()
         habit = fixtures.createLongHabit()
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/sqlite/SQLiteEntryListTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/sqlite/SQLiteEntryListTest.kt
index 2b7e37c6..7ecc663d 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/sqlite/SQLiteEntryListTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/sqlite/SQLiteEntryListTest.kt
@@ -19,25 +19,24 @@
 
 package org.isoron.uhabits.core.models.sqlite
 
+import kotlinx.coroutines.test.runTest
 import org.isoron.platform.time.LocalDate
 import org.isoron.uhabits.core.BaseUnitTest.Companion.buildMemoryDatabase
 import org.isoron.uhabits.core.database.EntryData
 import org.isoron.uhabits.core.models.Entry
 import org.isoron.uhabits.core.models.Entry.Companion.UNKNOWN
-import kotlin.test.BeforeTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
 class SQLiteEntryListTest {
 
-    private val database = buildMemoryDatabase()
-    private val factory = SQLModelFactory(database)
-    private val entryRepository = factory.entryRepository
+    private lateinit var factory: SQLModelFactory
     private lateinit var entries: SQLiteEntryList
     private val today = LocalDate(2015, 1, 25)
 
-    @BeforeTest
-    fun setUp() {
+    private suspend fun initTest() {
+        val database = buildMemoryDatabase()
+        factory = SQLModelFactory(database)
         val habitList = factory.buildHabitList()
         val habit = factory.buildHabit()
         habitList.add(habit)
@@ -45,16 +44,17 @@ class SQLiteEntryListTest {
     }
 
     @Test
-    fun testLoad() {
+    fun testLoad() = runTest {
+        initTest()
         val today = LocalDate(2015, 1, 25)
-        entryRepository.insert(
+        factory.entryRepository.insert(
             EntryData(
                 habitId = entries.habitId,
                 timestamp = today.unixTime,
                 value = 500
             )
         )
-        entryRepository.insert(
+        factory.entryRepository.insert(
             EntryData(
                 habitId = entries.habitId,
                 timestamp = today.minus(5).unixTime,
@@ -76,15 +76,16 @@ class SQLiteEntryListTest {
     }
 
     @Test
-    fun testAdd() {
+    fun testAdd() = runTest {
+        initTest()
         val habitId = entries.habitId!!
 
-        assertEquals(0, entryRepository.findAllByHabitId(habitId).size)
+        assertEquals(0, factory.entryRepository.findAllByHabitId(habitId).size)
 
         val original = Entry(today, 150)
         entries.add(original)
 
-        val all = entryRepository.findAllByHabitId(habitId)
+        val all = factory.entryRepository.findAllByHabitId(habitId)
         assertEquals(1, all.size)
         assertEquals(150, all[0].value)
         assertEquals(today.unixTime, all[0].timestamp)
@@ -92,7 +93,7 @@ class SQLiteEntryListTest {
         val replacement = Entry(today, 90)
         entries.add(replacement)
 
-        val all2 = entryRepository.findAllByHabitId(habitId)
+        val all2 = factory.entryRepository.findAllByHabitId(habitId)
         assertEquals(1, all2.size)
         assertEquals(90, all2[0].value)
     }
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/sqlite/SQLiteHabitListTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/sqlite/SQLiteHabitListTest.kt
index 3e882c46..67380a41 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/sqlite/SQLiteHabitListTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/models/sqlite/SQLiteHabitListTest.kt
@@ -20,6 +20,7 @@ package org.isoron.uhabits.core.models.sqlite
 
 import dev.mokkery.mock
 import dev.mokkery.verify
+import kotlinx.coroutines.test.runTest
 import org.isoron.uhabits.core.BaseUnitTest
 import org.isoron.uhabits.core.database.HabitRepository
 import org.isoron.uhabits.core.models.Habit
@@ -29,7 +30,6 @@ import org.isoron.uhabits.core.models.ModelObservable
 import org.isoron.uhabits.core.models.Reminder
 import org.isoron.uhabits.core.models.WeekdayList
 import org.isoron.uhabits.core.test.HabitFixtures
-import kotlin.test.AfterTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFailsWith
@@ -42,8 +42,7 @@ class SQLiteHabitListTest : BaseUnitTest() {
     private lateinit var activeHabits: HabitList
     private lateinit var reminderHabits: HabitList
 
-    override fun setUp() {
-        super.setUp()
+    private suspend fun initDb() {
         val db = buildMemoryDatabase()
         modelFactory = SQLModelFactory(db)
         habitList = SQLiteHabitList(modelFactory)
@@ -72,13 +71,17 @@ class SQLiteHabitListTest : BaseUnitTest() {
         habitList.observable.addListener(listener)
     }
 
-    @AfterTest
-    fun tearDown() {
-        habitList.observable.removeListener(listener)
+    private fun dbTest(block: suspend () -> Unit) = runTest {
+        initDb()
+        try {
+            block()
+        } finally {
+            habitList.observable.removeListener(listener)
+        }
     }
 
     @Test
-    fun testAdd_withDuplicate() {
+    fun testAdd_withDuplicate() = dbTest {
         val habit = modelFactory.buildHabit()
         habitList.add(habit)
         verify { listener.onModelChange() }
@@ -88,7 +91,7 @@ class SQLiteHabitListTest : BaseUnitTest() {
     }
 
     @Test
-    fun testAdd_withId() {
+    fun testAdd_withId() = dbTest {
         val habit = modelFactory.buildHabit()
         habit.name = "Hello world with id"
         habit.id = 12300L
@@ -100,7 +103,7 @@ class SQLiteHabitListTest : BaseUnitTest() {
     }
 
     @Test
-    fun testAdd_withoutId() {
+    fun testAdd_withoutId() = dbTest {
         val habit = modelFactory.buildHabit()
         habit.name = "Hello world"
         assertNull(habit.id)
@@ -111,12 +114,12 @@ class SQLiteHabitListTest : BaseUnitTest() {
     }
 
     @Test
-    fun testSize() {
+    fun testSize() = dbTest {
         assertEquals(10, habitList.size())
     }
 
     @Test
-    fun testGetById() {
+    fun testGetById() = dbTest {
         val h1 = habitList.getById(1)!!
         assertEquals("habit 1", h1.name)
         val h2 = habitList.getById(2)!!
@@ -124,20 +127,20 @@ class SQLiteHabitListTest : BaseUnitTest() {
     }
 
     @Test
-    fun testGetById_withInvalid() {
+    fun testGetById_withInvalid() = dbTest {
         val invalidId = 9183792001L
         val h1 = habitList.getById(invalidId)
         assertNull(h1)
     }
 
     @Test
-    fun testGetByPosition() {
+    fun testGetByPosition() = dbTest {
         val h = habitList.getByPosition(4)
         assertEquals("habit 5", h.name)
     }
 
     @Test
-    fun testIndexOf() {
+    fun testIndexOf() = dbTest {
         val h1 = habitList.getByPosition(5)
         assertEquals(5, habitList.indexOf(h1))
         val h2 = modelFactory.buildHabit()
@@ -147,7 +150,7 @@ class SQLiteHabitListTest : BaseUnitTest() {
     }
 
     @Test
-    fun testRemove() {
+    fun testRemove() = dbTest {
         val h = habitList.getById(2)
         habitList.remove(h!!)
         assertEquals(-1, habitList.indexOf(h))
@@ -160,7 +163,7 @@ class SQLiteHabitListTest : BaseUnitTest() {
     }
 
     @Test
-    fun testRemove_orderByName() {
+    fun testRemove_orderByName() = dbTest {
         habitList.primaryOrder = HabitList.Order.BY_NAME_DESC
         val h = habitList.getById(2)
         habitList.remove(h!!)
@@ -174,7 +177,7 @@ class SQLiteHabitListTest : BaseUnitTest() {
     }
 
     @Test
-    fun testReorder() {
+    fun testReorder() = dbTest {
         val habit3 = habitList.getById(3)!!
         val habit4 = habitList.getById(4)!!
         habitList.reorder(habit4, habit3)
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/tasks/SingleThreadTaskRunnerTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/tasks/SingleThreadTaskRunnerTest.kt
index ee546892..97cb93b3 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/tasks/SingleThreadTaskRunnerTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/tasks/SingleThreadTaskRunnerTest.kt
@@ -22,13 +22,14 @@ import dev.mokkery.mock
 import dev.mokkery.verify
 import dev.mokkery.verify.VerifyMode.Companion.order
 import org.isoron.uhabits.core.BaseUnitTest
+import kotlin.test.BeforeTest
 import kotlin.test.Test
 
 class SingleThreadTaskRunnerTest : BaseUnitTest() {
     private lateinit var runner: SingleThreadTaskRunner
     private var task: Task = mock()
 
-    @Throws(Exception::class)
+    @BeforeTest
     override fun setUp() {
         super.setUp()
         runner = SingleThreadTaskRunner()
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/HabitCardListCacheTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/HabitCardListCacheTest.kt
index 83c64d4f..216dbe50 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/HabitCardListCacheTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/HabitCardListCacheTest.kt
@@ -27,6 +27,7 @@ import org.isoron.uhabits.core.BaseUnitTest
 import org.isoron.uhabits.core.commands.CreateRepetitionCommand
 import org.isoron.uhabits.core.commands.DeleteHabitsCommand
 import org.isoron.uhabits.core.models.Entry
+import kotlin.test.BeforeTest
 import kotlin.test.Test
 import kotlin.test.assertContentEquals
 import kotlin.test.assertEquals
@@ -36,7 +37,7 @@ class HabitCardListCacheTest : BaseUnitTest() {
     private lateinit var listener: HabitCardListCache.Listener
     var today = LocalDate(2015, 1, 25)
 
-    @Throws(Exception::class)
+    @BeforeTest
     override fun setUp() {
         super.setUp()
         habitList.removeAll()
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/HintListTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/HintListTest.kt
index bd4ced89..1688ee1f 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/HintListTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/HintListTest.kt
@@ -26,6 +26,7 @@ import org.isoron.platform.time.LocalDate
 import org.isoron.platform.time.getToday
 import org.isoron.uhabits.core.BaseUnitTest
 import org.isoron.uhabits.core.preferences.Preferences
+import kotlin.test.BeforeTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
@@ -40,7 +41,7 @@ class HintListTest : BaseUnitTest() {
     private lateinit var today: LocalDate
     private lateinit var yesterday: LocalDate
 
-    @Throws(Exception::class)
+    @BeforeTest
     override fun setUp() {
         super.setUp()
         today = getToday()
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsBehaviorTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsBehaviorTest.kt
index 5dea98b2..f51803d3 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsBehaviorTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsBehaviorTest.kt
@@ -26,14 +26,15 @@ import dev.mokkery.matcher.any
 import dev.mokkery.mock
 import dev.mokkery.spy
 import dev.mokkery.verify
+import kotlinx.coroutines.test.runTest
 import org.isoron.platform.io.UserFile
-import org.isoron.platform.runSuspend
 import org.isoron.platform.time.getToday
 import org.isoron.uhabits.core.BaseUnitTest
 import org.isoron.uhabits.core.models.Entry
 import org.isoron.uhabits.core.models.Habit
 import org.isoron.uhabits.core.preferences.Preferences
 import org.isoron.uhabits.core.ui.callbacks.NumberPickerCallback
+import kotlin.test.BeforeTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
@@ -53,6 +54,7 @@ class ListHabitsBehaviorTest : BaseUnitTest() {
 
     private val bugReporter: ListHabitsBehavior.BugReporter = mock()
 
+    @BeforeTest
     override fun setUp() {
         super.setUp()
         habit1 = fixtures.createShortHabit()
@@ -89,12 +91,12 @@ class ListHabitsBehaviorTest : BaseUnitTest() {
     }
 
     @Test
-    fun testOnExportCSV() {
+    fun testOnExportCSV() = runTest {
         val outputDir = createTempDir()
         every { dirFinder.getCSVOutputDir() } returns outputDir
         behavior.onExportCSV()
         verify { screen.showSendFileScreen(any()) }
-        val files = runSuspend { outputDir.listFiles() }
+        val files = outputDir.listFiles()
         assertEquals(1, files!!.size)
     }
 
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsMenuBehaviorTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsMenuBehaviorTest.kt
index 32cac200..92e77f6c 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsMenuBehaviorTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsMenuBehaviorTest.kt
@@ -30,6 +30,7 @@ import org.isoron.uhabits.core.models.HabitList
 import org.isoron.uhabits.core.models.HabitMatcher
 import org.isoron.uhabits.core.preferences.Preferences
 import org.isoron.uhabits.core.ui.ThemeSwitcher
+import kotlin.test.BeforeTest
 import kotlin.test.Test
 import dev.mokkery.verify.VerifyMode.Companion.not as notCalled
 
@@ -48,7 +49,7 @@ class ListHabitsMenuBehaviorTest : BaseUnitTest() {
     private var capturedOrder: HabitList.Order? = null
     private var capturedSecondaryOrder: HabitList.Order? = null
 
-    @Throws(Exception::class)
+    @BeforeTest
     override fun setUp() {
         super.setUp()
         every { adapter.setFilter(any()) } returns Unit
@@ -80,6 +81,7 @@ class ListHabitsMenuBehaviorTest : BaseUnitTest() {
 
     @Test
     fun testOnSortByColor() {
+        every { adapter.primaryOrder } returns HabitList.Order.BY_POSITION
         behavior.onSortByColor()
         verify { adapter.primaryOrder = HabitList.Order.BY_COLOR_ASC }
     }
@@ -92,12 +94,14 @@ class ListHabitsMenuBehaviorTest : BaseUnitTest() {
 
     @Test
     fun testOnSortScore() {
+        every { adapter.primaryOrder } returns HabitList.Order.BY_POSITION
         behavior.onSortByScore()
         verify { adapter.primaryOrder = HabitList.Order.BY_SCORE_DESC }
     }
 
     @Test
     fun testOnSortName() {
+        every { adapter.primaryOrder } returns HabitList.Order.BY_POSITION
         behavior.onSortByName()
         verify { adapter.primaryOrder = HabitList.Order.BY_NAME_ASC }
     }
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsSelectionMenuBehaviorTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsSelectionMenuBehaviorTest.kt
index 9582a581..a16fc5ba 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsSelectionMenuBehaviorTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsSelectionMenuBehaviorTest.kt
@@ -29,6 +29,7 @@ import org.isoron.uhabits.core.models.Habit
 import org.isoron.uhabits.core.models.PaletteColor
 import org.isoron.uhabits.core.ui.callbacks.OnColorPickedCallback
 import org.isoron.uhabits.core.ui.callbacks.OnConfirmedCallback
+import kotlin.test.BeforeTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
@@ -130,7 +131,7 @@ class ListHabitsSelectionMenuBehaviorTest : BaseUnitTest() {
         assertFalse(habit1.isArchived)
     }
 
-    @Throws(Exception::class)
+    @BeforeTest
     override fun setUp() {
         super.setUp()
         habit1 = fixtures.createShortHabit()
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/show/ShowHabitMenuPresenterTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/show/ShowHabitMenuPresenterTest.kt
index 7fe136fe..5428001e 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/show/ShowHabitMenuPresenterTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/uhabits/core/ui/screens/habits/show/ShowHabitMenuPresenterTest.kt
@@ -22,9 +22,10 @@ import dev.mokkery.answering.returns
 import dev.mokkery.every
 import dev.mokkery.mock
 import dev.mokkery.verify
-import org.isoron.platform.runSuspend
+import kotlinx.coroutines.test.runTest
 import org.isoron.uhabits.core.BaseUnitTest
 import org.isoron.uhabits.core.models.Habit
+import kotlin.test.BeforeTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
@@ -34,6 +35,7 @@ class ShowHabitMenuPresenterTest : BaseUnitTest() {
     private lateinit var habit: Habit
     private lateinit var menu: ShowHabitMenuPresenter
 
+    @BeforeTest
     override fun setUp() {
         super.setUp()
         system = mock()
@@ -56,11 +58,11 @@ class ShowHabitMenuPresenterTest : BaseUnitTest() {
     }
 
     @Test
-    fun testOnExport() {
+    fun testOnExport() = runTest {
         val outputDir = createTempDir()
         every { system.getCSVOutputDir() } returns outputDir
         menu.onExportCSV()
-        val files = runSuspend { outputDir.listFiles() }
+        val files = outputDir.listFiles()
         assertEquals(1, files!!.size)
     }
 }
diff --git a/uhabits-core/src/jsMain/kotlin/org/isoron/platform/RunSuspend.kt b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/RunSuspend.kt
new file mode 100644
index 00000000..abcfefbc
--- /dev/null
+++ b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/RunSuspend.kt
@@ -0,0 +1,21 @@
+package org.isoron.platform
+
+import kotlin.coroutines.Continuation
+import kotlin.coroutines.EmptyCoroutineContext
+import kotlin.coroutines.startCoroutine
+
+actual fun <T> runSuspend(block: suspend () -> T): T {
+    var result: Result<T>? = null
+    block.startCoroutine(
+        object : Continuation<T> {
+            override val context = EmptyCoroutineContext
+            override fun resumeWith(r: Result<T>) {
+                result = r
+            }
+        }
+    )
+    return result?.getOrThrow()
+        ?: throw IllegalStateException(
+            "runSuspend: coroutine did not complete synchronously"
+        )
+}
diff --git a/uhabits-core/src/jsMain/kotlin/org/isoron/platform/gui/JsCanvas.kt b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/gui/JsCanvas.kt
new file mode 100644
index 00000000..b569d23d
--- /dev/null
+++ b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/gui/JsCanvas.kt
@@ -0,0 +1,162 @@
+package org.isoron.platform.gui
+
+import kotlinx.browser.document
+import org.w3c.dom.CanvasRenderingContext2D
+import org.w3c.dom.HTMLCanvasElement
+import kotlin.math.PI
+import kotlin.math.roundToInt
+
+class JsCanvas(
+    private val canvas: HTMLCanvasElement,
+    private val pixelScale: Double = 2.0
+) : Canvas {
+    private val ctx = canvas.getContext("2d") as CanvasRenderingContext2D
+    private var fontSize = 12.0
+    private var font = Font.REGULAR
+    private var textAlign = TextAlign.CENTER
+
+    init {
+        updateFont()
+    }
+
+    private fun toPixel(x: Double): Double = pixelScale * x
+    private fun toDp(x: Double): Double = x / pixelScale
+
+    override fun setColor(color: Color) {
+        val r = (color.red * 255).roundToInt()
+        val g = (color.green * 255).roundToInt()
+        val b = (color.blue * 255).roundToInt()
+        val a = color.alpha
+        val css = "rgba($r,$g,$b,$a)"
+        ctx.fillStyle = css
+        ctx.strokeStyle = css
+    }
+
+    override fun drawLine(x1: Double, y1: Double, x2: Double, y2: Double) {
+        ctx.beginPath()
+        ctx.moveTo(toPixel(x1), toPixel(y1))
+        ctx.lineTo(toPixel(x2), toPixel(y2))
+        ctx.stroke()
+    }
+
+    override fun drawText(text: String, x: Double, y: Double) {
+        updateFont()
+        val px = toPixel(x)
+        val py = toPixel(y)
+        val metrics = ctx.measureText(text)
+        val textWidth = metrics.width
+        val xPos = when (textAlign) {
+            TextAlign.CENTER -> px - textWidth / 2
+            TextAlign.RIGHT -> px - textWidth
+            TextAlign.LEFT -> px
+        }
+        ctx.fillText(text, xPos, py)
+    }
+
+    override fun fillRect(x: Double, y: Double, width: Double, height: Double) {
+        ctx.fillRect(toPixel(x), toPixel(y), toPixel(width), toPixel(height))
+    }
+
+    override fun fillRoundRect(
+        x: Double,
+        y: Double,
+        width: Double,
+        height: Double,
+        cornerRadius: Double
+    ) {
+        val px = toPixel(x)
+        val py = toPixel(y)
+        val pw = toPixel(width)
+        val ph = toPixel(height)
+        val pr = toPixel(cornerRadius)
+        ctx.beginPath()
+        ctx.moveTo(px + pr, py)
+        ctx.arcTo(px + pw, py, px + pw, py + ph, pr)
+        ctx.arcTo(px + pw, py + ph, px, py + ph, pr)
+        ctx.arcTo(px, py + ph, px, py, pr)
+        ctx.arcTo(px, py, px + pw, py, pr)
+        ctx.closePath()
+        ctx.fill()
+    }
+
+    override fun drawRect(x: Double, y: Double, width: Double, height: Double) {
+        ctx.strokeRect(toPixel(x), toPixel(y), toPixel(width), toPixel(height))
+    }
+
+    override fun getHeight(): Double = toDp(canvas.height.toDouble())
+    override fun getWidth(): Double = toDp(canvas.width.toDouble())
+
+    override fun setFont(font: Font) {
+        this.font = font
+        updateFont()
+    }
+
+    override fun setFontSize(size: Double) {
+        this.fontSize = size
+        updateFont()
+    }
+
+    override fun setStrokeWidth(size: Double) {
+        ctx.lineWidth = size * pixelScale
+    }
+
+    override fun fillArc(
+        centerX: Double,
+        centerY: Double,
+        radius: Double,
+        startAngle: Double,
+        swipeAngle: Double
+    ) {
+        val cx = toPixel(centerX)
+        val cy = toPixel(centerY)
+        val r = toPixel(radius)
+        val start = -startAngle * PI / 180.0
+        val end = -(startAngle + swipeAngle) * PI / 180.0
+        ctx.beginPath()
+        ctx.moveTo(cx, cy)
+        ctx.arc(cx, cy, r, start, end, swipeAngle > 0)
+        ctx.closePath()
+        ctx.fill()
+    }
+
+    override fun fillCircle(centerX: Double, centerY: Double, radius: Double) {
+        val cx = toPixel(centerX)
+        val cy = toPixel(centerY)
+        val r = toPixel(radius)
+        ctx.beginPath()
+        ctx.arc(cx, cy, r, 0.0, 2 * PI)
+        ctx.fill()
+    }
+
+    override fun setTextAlign(align: TextAlign) {
+        this.textAlign = align
+    }
+
+    override fun toImage(): Image = JsImage(canvas)
+
+    override fun measureText(text: String): Double {
+        updateFont()
+        return toDp(ctx.measureText(text).width)
+    }
+
+    private fun updateFont() {
+        val sizePx = (fontSize * pixelScale).roundToInt()
+        val family = when (font) {
+            Font.REGULAR -> "NotoSans"
+            Font.BOLD -> "NotoSansBold"
+            Font.FONT_AWESOME -> "FontAwesome"
+        }
+        val weight = if (font == Font.BOLD) "bold" else "normal"
+        ctx.font = "$weight ${sizePx}px $family"
+        ctx.asDynamic().textBaseline = "middle"
+    }
+
+    companion object {
+        fun create(width: Int, height: Int, pixelScale: Double = 2.0): JsCanvas {
+            val canvas = document.createElement("canvas") as HTMLCanvasElement
+            canvas.width = (width * pixelScale).roundToInt()
+            canvas.height = (height * pixelScale).roundToInt()
+            return JsCanvas(canvas, pixelScale)
+        }
+    }
+}
diff --git a/uhabits-core/src/jsMain/kotlin/org/isoron/platform/gui/JsImage.kt b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/gui/JsImage.kt
new file mode 100644
index 00000000..d0a132e2
--- /dev/null
+++ b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/gui/JsImage.kt
@@ -0,0 +1,45 @@
+package org.isoron.platform.gui
+
+import kotlinx.browser.document
+import org.w3c.dom.CanvasRenderingContext2D
+import org.w3c.dom.HTMLCanvasElement
+
+class JsImage(private val canvas: HTMLCanvasElement) : Image {
+    private val ctx = canvas.getContext("2d") as CanvasRenderingContext2D
+
+    override val width: Int get() = canvas.width
+    override val height: Int get() = canvas.height
+
+    override fun getPixel(x: Int, y: Int): Color {
+        val data = ctx.getImageData(x.toDouble(), y.toDouble(), 1.0, 1.0)
+        val d = data.data.asDynamic()
+        val r = (d[0] as Number).toDouble() / 255.0
+        val g = (d[1] as Number).toDouble() / 255.0
+        val b = (d[2] as Number).toDouble() / 255.0
+        val a = (d[3] as Number).toDouble() / 255.0
+        return Color(r, g, b, a)
+    }
+
+    override fun setPixel(x: Int, y: Int, color: Color) {
+        val data = ctx.createImageData(1.0, 1.0)
+        val d = data.data.asDynamic()
+        d[0] = (color.red * 255).toInt()
+        d[1] = (color.green * 255).toInt()
+        d[2] = (color.blue * 255).toInt()
+        d[3] = (color.alpha * 255).toInt()
+        ctx.putImageData(data, x.toDouble(), y.toDouble())
+    }
+
+    override suspend fun export(path: String) {
+        // No-op on JS browser; images can't be exported to filesystem
+    }
+
+    companion object {
+        fun create(width: Int, height: Int): JsImage {
+            val canvas = document.createElement("canvas") as HTMLCanvasElement
+            canvas.width = width
+            canvas.height = height
+            return JsImage(canvas)
+        }
+    }
+}
diff --git a/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsDatabase.kt b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsDatabase.kt
new file mode 100644
index 00000000..b6552234
--- /dev/null
+++ b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsDatabase.kt
@@ -0,0 +1,126 @@
+package org.isoron.platform.io
+
+import org.khronos.webgl.Uint8Array
+import org.khronos.webgl.set
+import kotlin.js.Promise
+
+@JsModule("sql.js")
+@JsNonModule
+external fun initSqlJs(config: dynamic = definedExternally): Promise<dynamic>
+
+private fun sqlJsNewDatabase(sqlJs: dynamic): dynamic {
+    val ctor = sqlJs.Database
+    return js("new ctor()")
+}
+
+class JsPreparedStatement(
+    private val db: dynamic,
+    sql: String
+) : PreparedStatement {
+    private val stmt: dynamic = db.prepare(sql)
+    private var currentRow: dynamic = null
+    private var bindings: dynamic = js("[]")
+    private var needsBind: Boolean = false
+
+    override fun step(): StepResult {
+        if (needsBind) {
+            stmt.bind(bindings)
+            needsBind = false
+        }
+        val hasRow = stmt.step() as Boolean
+        currentRow = if (hasRow) stmt.get() else null
+        return if (hasRow) StepResult.ROW else StepResult.DONE
+    }
+
+    override fun getInt(index: Int): Int = (currentRow[index] as Number).toInt()
+    override fun getLong(index: Int): Long = (currentRow[index] as Number).toLong()
+    override fun getReal(index: Int): Double = (currentRow[index] as Number).toDouble()
+    override fun getText(index: Int): String = currentRow[index] as String
+
+    override fun getIntOrNull(index: Int): Int? {
+        val v = currentRow[index] ?: return null
+        return (v as Number).toInt()
+    }
+
+    override fun getLongOrNull(index: Int): Long? {
+        val v = currentRow[index] ?: return null
+        return (v as Number).toLong()
+    }
+
+    override fun getRealOrNull(index: Int): Double? {
+        val v = currentRow[index] ?: return null
+        return (v as Number).toDouble()
+    }
+
+    override fun getTextOrNull(index: Int): String? {
+        val v = currentRow[index] ?: return null
+        return v as String
+    }
+
+    override fun bindInt(index: Int, value: Int) {
+        bindings[index - 1] = value
+        needsBind = true
+    }
+
+    override fun bindLong(index: Int, value: Long) {
+        bindings[index - 1] = value.toDouble()
+        needsBind = true
+    }
+
+    override fun bindReal(index: Int, value: Double) {
+        bindings[index - 1] = value
+        needsBind = true
+    }
+
+    override fun bindText(index: Int, value: String) {
+        bindings[index - 1] = value
+        needsBind = true
+    }
+
+    override fun bindNull(index: Int) {
+        bindings[index - 1] = null
+        needsBind = true
+    }
+
+    override fun reset() {
+        stmt.reset()
+        currentRow = null
+        bindings = js("[]")
+        needsBind = false
+    }
+
+    override fun finalize() {
+        stmt.free()
+    }
+}
+
+class JsDatabase(val db: dynamic) : Database {
+    override fun prepareStatement(sql: String): PreparedStatement {
+        return JsPreparedStatement(db, sql)
+    }
+
+    override fun close() {
+        db.close()
+    }
+}
+
+class JsDatabaseOpener(
+    private val sqlJs: dynamic,
+    private val storage: JsFileStorage? = null
+) : DatabaseOpener {
+    override fun open(path: String): Database {
+        if (path == ":memory:" || storage == null) {
+            val db = sqlJsNewDatabase(sqlJs)
+            return JsDatabase(db)
+        }
+        val bytes = storage.read(path)
+            ?: error("File not found in storage: $path")
+        val data = Uint8Array(bytes.size)
+        for (i in bytes.indices) {
+            data[i] = bytes[i]
+        }
+        val ctor = sqlJs.Database
+        val db = js("new ctor(data)")
+        return JsDatabase(db)
+    }
+}
diff --git a/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsFiles.kt b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsFiles.kt
new file mode 100644
index 00000000..489baed6
--- /dev/null
+++ b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsFiles.kt
@@ -0,0 +1,184 @@
+package org.isoron.platform.io
+
+import kotlinx.browser.window
+import org.isoron.platform.gui.Image
+import org.isoron.platform.gui.JsImage
+import org.w3c.dom.CanvasRenderingContext2D
+import org.w3c.dom.HTMLCanvasElement
+import kotlin.coroutines.resume
+import kotlin.coroutines.resumeWithException
+import kotlin.coroutines.suspendCoroutine
+import kotlin.js.Promise
+
+private fun <T> Promise<T>.await(): suspend () -> T = {
+    suspendCoroutine { cont ->
+        then({ cont.resume(it) }, { cont.resumeWithException(it) })
+    }
+}
+
+class JsFileStorage {
+    private val store = mutableMapOf<String, ByteArray>()
+
+    fun write(path: String, bytes: ByteArray) {
+        store[path] = bytes
+    }
+
+    fun read(path: String): ByteArray? = store[path]
+
+    fun exists(path: String): Boolean = path in store
+
+    fun delete(path: String) {
+        store.remove(path)
+    }
+
+    fun listKeys(prefix: String): List<String> =
+        store.keys.filter { it.startsWith(prefix) }
+}
+
+class JsUserFile(
+    private val storage: JsFileStorage,
+    override val pathString: String
+) : UserFile {
+    override suspend fun delete() {
+        storage.delete(pathString)
+    }
+
+    override suspend fun exists(): Boolean = storage.exists(pathString)
+
+    override suspend fun lines(): List<String> {
+        val bytes = storage.read(pathString)
+            ?: error("File not found: $pathString")
+        return bytes.decodeToString().lines()
+    }
+
+    override suspend fun writeString(content: String) {
+        storage.write(pathString, content.encodeToByteArray())
+    }
+
+    override suspend fun writeBytes(bytes: ByteArray) {
+        storage.write(pathString, bytes)
+    }
+
+    override suspend fun readBytes(limit: Int): ByteArray {
+        val bytes = storage.read(pathString) ?: return ByteArray(0)
+        return if (bytes.size <= limit) bytes else bytes.copyOf(limit)
+    }
+
+    override fun resolve(child: String): UserFile {
+        val resolved = if (pathString.endsWith("/")) {
+            "$pathString$child"
+        } else {
+            "$pathString/$child"
+        }
+        return JsUserFile(storage, resolved)
+    }
+
+    override suspend fun listFiles(): List<UserFile>? {
+        val prefix = if (pathString.endsWith("/")) pathString else "$pathString/"
+        val keys = storage.listKeys(prefix)
+        if (keys.isEmpty()) return null
+        val children = mutableSetOf<String>()
+        for (key in keys) {
+            val rest = key.removePrefix(prefix)
+            val child = rest.split("/").first()
+            children.add(child)
+        }
+        return children.map { JsUserFile(storage, "$prefix$it") }
+    }
+
+    override suspend fun mkdirs() {
+        // No-op for in-memory storage
+    }
+}
+
+class JsResourceFile(private val path: String) : ResourceFile {
+    override suspend fun copyTo(dest: UserFile) {
+        val bytes = fetchBytes(path)
+        dest.writeBytes(bytes)
+    }
+
+    override suspend fun lines(): List<String> {
+        val text = fetchText(path)
+        val result = text.lines()
+        return if (result.lastOrNull() == "") result.dropLast(1) else result
+    }
+
+    override suspend fun exists(): Boolean {
+        return try {
+            fetchText(path)
+            true
+        } catch (e: Throwable) {
+            false
+        }
+    }
+
+    override suspend fun toImage(): Image {
+        return suspendCoroutine { cont ->
+            val img = org.w3c.dom.Image()
+            img.onload = {
+                val canvas = (
+                    kotlinx.browser.document.createElement("canvas")
+                        as HTMLCanvasElement
+                    )
+                canvas.width = img.width
+                canvas.height = img.height
+                val ctx = canvas.getContext("2d") as CanvasRenderingContext2D
+                ctx.drawImage(img, 0.0, 0.0)
+                cont.resume(JsImage(canvas))
+            }
+            img.onerror = { _, _, _, _, _ ->
+                cont.resumeWithException(RuntimeException("Failed to load image: $path"))
+            }
+            img.src = path
+        }
+    }
+}
+
+private suspend fun fetchText(path: String): String = suspendCoroutine { cont ->
+    window.fetch(path).then(
+        { response ->
+            if (!response.ok) {
+                cont.resumeWithException(RuntimeException("Failed to fetch $path: ${response.status}"))
+            } else {
+                response.text().then(
+                    { text -> cont.resume(text) },
+                    { err -> cont.resumeWithException(RuntimeException("Failed to read $path: $err")) }
+                )
+            }
+        },
+        { err -> cont.resumeWithException(RuntimeException("Failed to fetch $path: $err")) }
+    )
+}
+
+private suspend fun fetchBytes(path: String): ByteArray = suspendCoroutine { cont ->
+    window.fetch(path).then(
+        { response ->
+            if (!response.ok) {
+                cont.resumeWithException(RuntimeException("Failed to fetch $path: ${response.status}"))
+            } else {
+                response.arrayBuffer().then(
+                    { buffer ->
+                        val uint8Array = js("new Uint8Array(buffer)")
+                        val length = uint8Array.length as Int
+                        val bytes = ByteArray(length)
+                        for (i in 0 until length) {
+                            bytes[i] = (uint8Array[i] as Number).toByte()
+                        }
+                        cont.resume(bytes)
+                    },
+                    { err -> cont.resumeWithException(RuntimeException("Failed to read $path: $err")) }
+                )
+            }
+        },
+        { err -> cont.resumeWithException(RuntimeException("Failed to fetch $path: $err")) }
+    )
+}
+
+class JsFileOpener(private val storage: JsFileStorage = JsFileStorage()) : FileOpener {
+    override fun openResourceFile(path: String): ResourceFile {
+        val url = if (path.startsWith("migrations/")) path else "test-assets/$path"
+        return JsResourceFile(url)
+    }
+
+    override fun openUserFile(path: String): UserFile = JsUserFile(storage, path)
+}
diff --git a/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsStrings.kt b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsStrings.kt
new file mode 100644
index 00000000..e1ae8dbe
--- /dev/null
+++ b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsStrings.kt
@@ -0,0 +1,16 @@
+package org.isoron.platform.io
+
+@JsModule("sprintf-js")
+@JsNonModule
+external object SprintfJs {
+    fun sprintf(format: String, vararg args: Any?): String
+}
+
+actual fun format(format: String, arg: String): String =
+    SprintfJs.sprintf(format, arg)
+
+actual fun format(format: String, arg: Int): String =
+    SprintfJs.sprintf(format, arg)
+
+actual fun format(format: String, arg: Double): String =
+    SprintfJs.sprintf(format, arg)
diff --git a/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsZipReader.kt b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsZipReader.kt
new file mode 100644
index 00000000..738ccb6d
--- /dev/null
+++ b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsZipReader.kt
@@ -0,0 +1,40 @@
+package org.isoron.platform.io
+
+actual class ZipReader actual constructor(bytes: ByteArray) {
+    private val data = bytes
+
+    actual fun entries(): List<ZipEntry> {
+        val result = mutableListOf<ZipEntry>()
+        var pos = 0
+        while (pos + 30 <= data.size) {
+            val sig = readInt(pos)
+            if (sig != 0x04034b50) break
+            val compressionMethod = readShort(pos + 8)
+            val compressedSize = readInt(pos + 18)
+            val nameLen = readShort(pos + 26)
+            val extraLen = readShort(pos + 28)
+            val nameStart = pos + 30
+            val name = data.copyOfRange(nameStart, nameStart + nameLen).decodeToString()
+            val dataStart = nameStart + nameLen + extraLen
+            if (compressionMethod != 0) {
+                throw UnsupportedOperationException(
+                    "Only STORED ZIP entries are supported, got method $compressionMethod"
+                )
+            }
+            val content = data.copyOfRange(dataStart, dataStart + compressedSize).decodeToString()
+            result.add(ZipEntry(name, content))
+            pos = dataStart + compressedSize
+        }
+        return result
+    }
+
+    private fun readInt(offset: Int): Int =
+        (data[offset].toInt() and 0xFF) or
+            ((data[offset + 1].toInt() and 0xFF) shl 8) or
+            ((data[offset + 2].toInt() and 0xFF) shl 16) or
+            ((data[offset + 3].toInt() and 0xFF) shl 24)
+
+    private fun readShort(offset: Int): Int =
+        (data[offset].toInt() and 0xFF) or
+            ((data[offset + 1].toInt() and 0xFF) shl 8)
+}
diff --git a/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsZipWriter.kt b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsZipWriter.kt
new file mode 100644
index 00000000..a438a79a
--- /dev/null
+++ b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/io/JsZipWriter.kt
@@ -0,0 +1,122 @@
+package org.isoron.platform.io
+
+actual class ZipWriter {
+    private val entries = mutableListOf<Pair<String, ByteArray>>()
+
+    actual fun addEntry(name: String, content: String) {
+        entries.add(name to content.encodeToByteArray())
+    }
+
+    actual suspend fun toBytes(): ByteArray {
+        val buf = ZipBuffer()
+        val offsets = mutableListOf<Int>()
+
+        for ((name, data) in entries) {
+            offsets.add(buf.size)
+            val nameBytes = name.encodeToByteArray()
+            val crc = crc32(data)
+            buf.writeInt(0x04034b50)
+            buf.writeShort(20)
+            buf.writeShort(0)
+            buf.writeShort(0)
+            buf.writeShort(0)
+            buf.writeShort(0)
+            buf.writeInt(crc)
+            buf.writeInt(data.size)
+            buf.writeInt(data.size)
+            buf.writeShort(nameBytes.size)
+            buf.writeShort(0)
+            buf.writeBytes(nameBytes)
+            buf.writeBytes(data)
+        }
+
+        val centralDirOffset = buf.size
+        for (i in entries.indices) {
+            val (name, data) = entries[i]
+            val nameBytes = name.encodeToByteArray()
+            val crc = crc32(data)
+            buf.writeInt(0x02014b50)
+            buf.writeShort(20)
+            buf.writeShort(20)
+            buf.writeShort(0)
+            buf.writeShort(0)
+            buf.writeShort(0)
+            buf.writeShort(0)
+            buf.writeInt(crc)
+            buf.writeInt(data.size)
+            buf.writeInt(data.size)
+            buf.writeShort(nameBytes.size)
+            buf.writeShort(0)
+            buf.writeShort(0)
+            buf.writeShort(0)
+            buf.writeShort(0)
+            buf.writeInt(0)
+            buf.writeInt(offsets[i])
+            buf.writeBytes(nameBytes)
+        }
+        val centralDirSize = buf.size - centralDirOffset
+
+        buf.writeInt(0x06054b50)
+        buf.writeShort(0)
+        buf.writeShort(0)
+        buf.writeShort(entries.size)
+        buf.writeShort(entries.size)
+        buf.writeInt(centralDirSize)
+        buf.writeInt(centralDirOffset)
+        buf.writeShort(0)
+
+        return buf.toByteArray()
+    }
+}
+
+private class ZipBuffer {
+    private var data = ByteArray(4096)
+    var size = 0
+        private set
+
+    fun writeShort(v: Int) {
+        ensureCapacity(2)
+        data[size++] = (v and 0xFF).toByte()
+        data[size++] = ((v shr 8) and 0xFF).toByte()
+    }
+
+    fun writeInt(v: Int) {
+        ensureCapacity(4)
+        data[size++] = (v and 0xFF).toByte()
+        data[size++] = ((v shr 8) and 0xFF).toByte()
+        data[size++] = ((v shr 16) and 0xFF).toByte()
+        data[size++] = ((v shr 24) and 0xFF).toByte()
+    }
+
+    fun writeBytes(bytes: ByteArray) {
+        ensureCapacity(bytes.size)
+        bytes.copyInto(data, size)
+        size += bytes.size
+    }
+
+    fun toByteArray(): ByteArray = data.copyOf(size)
+
+    private fun ensureCapacity(needed: Int) {
+        if (size + needed > data.size) {
+            data = data.copyOf(maxOf(data.size * 2, size + needed))
+        }
+    }
+}
+
+private val crcTable = IntArray(256).also { table ->
+    for (n in 0..255) {
+        var c = n
+        repeat(8) {
+            c = if (c and 1 != 0) (c ushr 1) xor 0xEDB88320.toInt() else c ushr 1
+        }
+        table[n] = c
+    }
+}
+
+private fun crc32(data: ByteArray): Int {
+    var crc = -1
+    for (b in data) {
+        crc = (crc ushr 8) xor crcTable[(crc xor b.toInt()) and 0xFF]
+    }
+    return crc xor -1
+}
diff --git a/uhabits-core/src/jsMain/kotlin/org/isoron/platform/time/JsDates.kt b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/time/JsDates.kt
new file mode 100644
index 00000000..758121c9
--- /dev/null
+++ b/uhabits-core/src/jsMain/kotlin/org/isoron/platform/time/JsDates.kt
@@ -0,0 +1,67 @@
+package org.isoron.platform.time
+
+import kotlin.js.Date
+
+actual fun computeToday(hourOffset: Int, minuteOffset: Int): LocalDate {
+    val now = Date()
+    val localMillis = now.getTime() + now.getTimezoneOffset() * 60000.0 * -1
+    val offsetMillis = hourOffset * 3600000.0 + minuteOffset * 60000.0
+    val adjustedMillis = localMillis - offsetMillis
+    val daysSinceEpoch = kotlin.math.floor(adjustedMillis / 86400000.0).toLong()
+    val daysSince2000 = (daysSinceEpoch - 10957).toInt()
+    return LocalDate(daysSince2000)
+}
+
+actual fun getFirstWeekdayNumberAccordingToLocale(): Int {
+    // JS Intl does not expose first day of week. Default to Sunday (1)
+    // matching java.util.Calendar convention where Sunday=1.
+    return 1
+}
+
+private fun toLocaleDateString(date: Date, locale: String, options: dynamic): String {
+    return js("date.toLocaleDateString(locale, options)").unsafeCast<String>()
+}
+
+class JsLocalDateFormatter(private val locale: String = "en-US") : LocalDateFormatter {
+    override fun shortWeekdayName(weekday: DayOfWeek): String {
+        val date = weekdayToJsDate(weekday)
+        return formatWeekday(date, "short")
+    }
+
+    override fun shortWeekdayName(date: LocalDate): String {
+        return formatWeekday(localDateToJsDate(date), "short")
+    }
+
+    override fun shortMonthName(date: LocalDate): String {
+        val jsDate = localDateToJsDate(date)
+        val options = js("{month: 'short', timeZone: 'UTC'}")
+        return toLocaleDateString(jsDate, locale, options)
+    }
+
+    override fun longWeekdayName(weekday: DayOfWeek): String {
+        val date = weekdayToJsDate(weekday)
+        return formatWeekday(date, "long")
+    }
+
+    override fun longMonthName(date: LocalDate): String {
+        val jsDate = localDateToJsDate(date)
+        val options = js("{month: 'long', timeZone: 'UTC'}")
+        return toLocaleDateString(jsDate, locale, options)
+    }
+
+    private fun formatWeekday(jsDate: Date, style: String): String {
+        val options = js("{timeZone: 'UTC'}")
+        options["weekday"] = style
+        return toLocaleDateString(jsDate, locale, options)
+    }
+
+    private fun localDateToJsDate(date: LocalDate): Date {
+        return Date(Date.UTC(date.year, date.month - 1, date.day))
+    }
+
+    private fun weekdayToJsDate(weekday: DayOfWeek): Date {
+        // Jan 2, 2000 is a Sunday
+        val dayOffset = weekday.daysSinceSunday
+        return Date(Date.UTC(2000, 0, 2 + dayOffset))
+    }
+}
diff --git a/uhabits-core/src/jsTest/kotlin/org/isoron/platform/io/TestDatabaseHelper.kt b/uhabits-core/src/jsTest/kotlin/org/isoron/platform/io/TestDatabaseHelper.kt
new file mode 100644
index 00000000..9b0917fc
--- /dev/null
+++ b/uhabits-core/src/jsTest/kotlin/org/isoron/platform/io/TestDatabaseHelper.kt
@@ -0,0 +1,68 @@
+package org.isoron.platform.io
+
+import org.isoron.uhabits.core.DATABASE_VERSION
+import org.isoron.uhabits.core.database.SQLParser
+import kotlin.coroutines.resume
+import kotlin.coroutines.resumeWithException
+import kotlin.coroutines.suspendCoroutine
+
+actual object TestDatabaseHelper {
+    private var sqlJs: dynamic = null
+    private val migrationCache = mutableMapOf<Int, String>()
+
+    private suspend fun ensureInitialized() {
+        if (sqlJs == null) {
+            sqlJs = suspendCoroutine<dynamic> { cont ->
+                initSqlJs().then(
+                    { result: dynamic -> cont.resume(result) },
+                    { err: dynamic -> cont.resumeWithException(RuntimeException("$err")) }
+                )
+            }
+            for (v in 9..DATABASE_VERSION) {
+                migrationCache[v] = fetchMigrationSQL(v)
+            }
+        }
+    }
+
+    actual suspend fun createEmptyDatabase(): Database {
+        ensureInitialized()
+        val db = JsDatabaseOpener(sqlJs).open(":memory:")
+        db.setVersion(8)
+        for (v in 9..DATABASE_VERSION) {
+            val commands = SQLParser.parse(migrationCache[v]!!)
+            for (cmd in commands) db.run(cmd)
+            db.setVersion(v)
+        }
+        return db
+    }
+
+    suspend fun getInitializedSqlJs(): dynamic {
+        ensureInitialized()
+        return sqlJs
+    }
+
+    actual suspend fun loadMigrationSQL(version: Int): String {
+        ensureInitialized()
+        return migrationCache[version]
+            ?: error("Migration SQL for version $version not found")
+    }
+
+    private suspend fun fetchMigrationSQL(version: Int): String {
+        val path = "migrations/${version.toString().padStart(2, '0')}.sql"
+        return suspendCoroutine { cont ->
+            kotlinx.browser.window.fetch(path).then(
+                { response ->
+                    if (!response.ok) {
+                        cont.resumeWithException(RuntimeException("Failed to fetch $path: ${response.status}"))
+                    } else {
+                        response.text().then(
+                            { text: String -> cont.resume(text) },
+                            { err: dynamic -> cont.resumeWithException(RuntimeException("$err")) }
+                        )
+                    }
+                },
+                { err: dynamic -> cont.resumeWithException(RuntimeException("$err")) }
+            )
+        }
+    }
+}
diff --git a/uhabits-core/src/jsTest/kotlin/org/isoron/platform/io/TestPlatformHelper.kt b/uhabits-core/src/jsTest/kotlin/org/isoron/platform/io/TestPlatformHelper.kt
new file mode 100644
index 00000000..d04d1489
--- /dev/null
+++ b/uhabits-core/src/jsTest/kotlin/org/isoron/platform/io/TestPlatformHelper.kt
@@ -0,0 +1,57 @@
+package org.isoron.platform.io
+
+import kotlinx.browser.document
+import org.isoron.platform.gui.Canvas
+import org.isoron.platform.gui.JsCanvas
+import org.isoron.platform.time.JsLocalDateFormatter
+import org.isoron.platform.time.LocalDateFormatter
+import kotlin.coroutines.resume
+import kotlin.coroutines.suspendCoroutine
+
+val sharedTestStorage = JsFileStorage()
+
+actual fun createTestFileOpener(): FileOpener = JsFileOpener(sharedTestStorage)
+actual fun createTestDatabaseOpener(): DatabaseOpener {
+    throw UnsupportedOperationException(
+        "createTestDatabaseOpener() requires async sql.js init. " +
+            "Use createTestDatabaseOpenerSuspend() instead."
+    )
+}
+
+actual suspend fun createTestDatabaseOpenerSuspend(): DatabaseOpener {
+    val sqlJs = TestDatabaseHelper.getInitializedSqlJs()
+    return JsDatabaseOpener(sqlJs, sharedTestStorage)
+}
+
+actual fun createTestCanvas(width: Int, height: Int): Canvas {
+    return JsCanvas.create(width, height, 2.0)
+}
+
+actual fun createTestDateFormatter(): LocalDateFormatter {
+    return JsLocalDateFormatter("en-US")
+}
+
+private var fontsLoaded = false
+
+actual suspend fun ensureFontsLoaded() {
+    if (fontsLoaded) return
+    val style = document.createElement("style")
+    style.textContent = buildString {
+        appendLine("@font-face { font-family: 'NotoSans'; src: url('/fonts/NotoSans-Regular.ttf') format('truetype'); }")
+        appendLine("@font-face { font-family: 'NotoSansBold'; src: url('/fonts/NotoSans-Bold.ttf') format('truetype'); }")
+        appendLine("@font-face { font-family: 'FontAwesome'; src: url('/fonts/FontAwesome.ttf') format('truetype'); }")
+    }
+    document.head?.appendChild(style)
+    loadFontAsync("12px NotoSans")
+    loadFontAsync("bold 12px NotoSansBold")
+    loadFontAsync("12px FontAwesome")
+    fontsLoaded = true
+}
+
+private suspend fun loadFontAsync(fontSpec: String) = suspendCoroutine<Unit> { cont ->
+    val promise = document.asDynamic().fonts.load(fontSpec)
+    promise.then(
+        { _: dynamic -> cont.resume(Unit) },
+        { _: dynamic -> cont.resume(Unit) }
+    )
+}
diff --git a/uhabits-core/src/jvmMain/java/org/isoron/platform/JvmAnnotations.kt b/uhabits-core/src/jvmMain/java/org/isoron/platform/JvmAnnotations.kt
new file mode 100644
index 00000000..9cdfc954
--- /dev/null
+++ b/uhabits-core/src/jvmMain/java/org/isoron/platform/JvmAnnotations.kt
@@ -0,0 +1,4 @@
+package org.isoron.platform
+
+actual typealias Synchronized = kotlin.jvm.Synchronized
+actual typealias JvmStatic = kotlin.jvm.JvmStatic
diff --git a/uhabits-core/src/jvmMain/java/org/isoron/platform/time/JvmDates.kt b/uhabits-core/src/jvmMain/java/org/isoron/platform/time/JvmDates.kt
index a8bb2ecc..3de3adb8 100644
--- a/uhabits-core/src/jvmMain/java/org/isoron/platform/time/JvmDates.kt
+++ b/uhabits-core/src/jvmMain/java/org/isoron/platform/time/JvmDates.kt
@@ -2,7 +2,7 @@ package org.isoron.platform.time
 
 import java.util.TimeZone
 
-fun computeToday(hourOffset: Int = 0, minuteOffset: Int = 0): LocalDate {
+actual fun computeToday(hourOffset: Int, minuteOffset: Int): LocalDate {
     val nowMillis = System.currentTimeMillis()
     val tz = TimeZone.getDefault()
     val localMillis = nowMillis + tz.getOffset(nowMillis)
diff --git a/uhabits-core/src/jvmTest/java/org/isoron/platform/io/TestDatabaseHelper.kt b/uhabits-core/src/jvmTest/java/org/isoron/platform/io/TestDatabaseHelper.kt
index 95ddf251..4d269550 100644
--- a/uhabits-core/src/jvmTest/java/org/isoron/platform/io/TestDatabaseHelper.kt
+++ b/uhabits-core/src/jvmTest/java/org/isoron/platform/io/TestDatabaseHelper.kt
@@ -1,24 +1,19 @@
 package org.isoron.platform.io
 
-import kotlinx.coroutines.runBlocking
 import org.isoron.uhabits.core.DATABASE_VERSION
 
 actual object TestDatabaseHelper {
     private val fileOpener = JavaFileOpener()
 
-    actual fun createEmptyDatabase(): Database {
+    actual suspend fun createEmptyDatabase(): Database {
         val db = JavaDatabaseOpener().open(":memory:")
         db.setVersion(8)
-        runBlocking {
-            db.migrateTo(DATABASE_VERSION) { v -> loadMigrationSQL(v) }
-        }
+        db.migrateTo(DATABASE_VERSION) { v -> loadMigrationSQL(v) }
         return db
     }
 
-    actual fun loadMigrationSQL(version: Int): String {
+    actual suspend fun loadMigrationSQL(version: Int): String {
         val path = "migrations/%02d.sql".format(version)
-        return runBlocking {
-            fileOpener.openResourceFile(path).lines().joinToString("\n")
-        }
+        return fileOpener.openResourceFile(path).lines().joinToString("\n")
     }
 }
diff --git a/uhabits-core/src/jvmTest/java/org/isoron/platform/io/TestPlatformHelper.kt b/uhabits-core/src/jvmTest/java/org/isoron/platform/io/TestPlatformHelper.kt
index 08b71ecf..7550b2b1 100644
--- a/uhabits-core/src/jvmTest/java/org/isoron/platform/io/TestPlatformHelper.kt
+++ b/uhabits-core/src/jvmTest/java/org/isoron/platform/io/TestPlatformHelper.kt
@@ -10,6 +10,7 @@ import java.util.Locale
 
 actual fun createTestFileOpener(): FileOpener = JavaFileOpener()
 actual fun createTestDatabaseOpener(): DatabaseOpener = JavaDatabaseOpener()
+actual suspend fun createTestDatabaseOpenerSuspend(): DatabaseOpener = JavaDatabaseOpener()
 
 actual fun createTestCanvas(width: Int, height: Int): Canvas {
     return JavaCanvas(BufferedImage(2 * width, 2 * height, TYPE_INT_ARGB), 2.0)
@@ -18,3 +19,5 @@ actual fun createTestCanvas(width: Int, height: Int): Canvas {
 actual fun createTestDateFormatter(): LocalDateFormatter {
     return JavaLocalDateFormatter(Locale.US)
 }
+
+actual suspend fun ensureFontsLoaded() {}