Replace java.io.File with multiplatform Files abstraction

uhabits-android/src/main/java/org/isoron/platform/io/AndroidFiles.kt

@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2016-2025 Álinson Santos Xavier <git@axavier.org>
+ *
+ * This file is part of Loop Habit Tracker.
+ *
+ * Loop Habit Tracker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * Loop Habit Tracker is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.isoron.platform.io
+
+import android.content.res.AssetManager
+import android.graphics.BitmapFactory
+import org.isoron.platform.gui.AndroidImage
+import org.isoron.platform.gui.Image
+import java.io.File
+import java.io.IOException
+
+class AndroidResourceFile(
+    private val assets: AssetManager,
+    private val path: String
+) : ResourceFile {
+    override suspend fun lines(): List<String> {
+        return assets.open(path).bufferedReader().readLines()
+    }
+
+    override suspend fun exists(): Boolean {
+        return try {
+            assets.open(path).close()
+            true
+        } catch (e: IOException) {
+            false
+        }
+    }
+
+    override suspend fun copyTo(dest: UserFile) {
+        val bytes = assets.open(path).use { it.readBytes() }
+        dest.writeBytes(bytes)
+    }
+
+    override suspend fun toImage(): Image {
+        val bitmap = assets.open(path).use { BitmapFactory.decodeStream(it) }
+        return AndroidImage(bitmap)
+    }
+}
+
+class AndroidFileOpener(
+    private val assets: AssetManager,
+    private val filesDir: File
+) : FileOpener {
+    override fun openResourceFile(path: String): ResourceFile {
+        return AndroidResourceFile(assets, path)
+    }
+
+    override fun openUserFile(path: String): UserFile {
+        return JavaUserFile(File(filesDir, path).toPath())
+    }
+}

uhabits-android/src/main/java/org/isoron/uhabits/HabitsDatabaseOpener.kt

@@ -22,6 +22,7 @@ package org.isoron.uhabits
 import android.content.Context
 import android.database.sqlite.SQLiteDatabase
 import android.database.sqlite.SQLiteOpenHelper
+import kotlinx.coroutines.runBlocking
 import org.isoron.platform.io.migrateTo
 import org.isoron.platform.io.setVersion
 import org.isoron.uhabits.core.database.UnsupportedDatabaseVersionException
@@ -53,9 +54,11 @@ class HabitsDatabaseOpener(
         if (db.version < 8) throw UnsupportedDatabaseVersionException()
         val wrappedDb = AndroidDatabase(db)
         wrappedDb.setVersion(db.version)
-        wrappedDb.migrateTo(newVersion) { version ->
+        runBlocking {
-            val filename = "%02d.sql".format(version)
+            wrappedDb.migrateTo(newVersion) { version ->
-            context.assets.open("migrations/$filename").bufferedReader().readText()
+                val filename = "%02d.sql".format(version)
+                context.assets.open("migrations/$filename").bufferedReader().readText()
+            }
         }
     }
 

uhabits-android/src/main/java/org/isoron/uhabits/activities/HabitsDirFinder.kt

@@ -22,14 +22,13 @@ import me.tatarka.inject.annotations.Inject
 import org.isoron.uhabits.AndroidDirFinder
 import org.isoron.uhabits.core.ui.screens.habits.list.ListHabitsBehavior
 import org.isoron.uhabits.core.ui.screens.habits.show.ShowHabitMenuPresenter
-import java.io.File
 
 @Inject
 class HabitsDirFinder(
     private val androidDirFinder: AndroidDirFinder
 ) : ShowHabitMenuPresenter.System, ListHabitsBehavior.DirFinder {
 
-    override fun getCSVOutputDir(): File {
+    override fun getCSVOutputDir(): String {
-        return androidDirFinder.getFilesDir("CSV")!!
+        return androidDirFinder.getFilesDir("CSV")!!.absolutePath
     }
 }

uhabits-android/src/main/java/org/isoron/uhabits/activities/habits/list/ListHabitsScreen.kt

@@ -30,6 +30,7 @@ import nl.dionsegijn.konfetti.core.Party
 import nl.dionsegijn.konfetti.core.Position
 import nl.dionsegijn.konfetti.core.emitter.Emitter
 import org.isoron.platform.gui.toInt
+import org.isoron.platform.io.JavaUserFile
 import org.isoron.uhabits.R
 import org.isoron.uhabits.activities.common.dialogs.CheckmarkDialog
 import org.isoron.uhabits.activities.common.dialogs.ColorPickerDialogFactory
@@ -137,7 +138,7 @@ class ListHabitsScreen(
             val cacheDir = activity.externalCacheDir
             val tempFile = File.createTempFile("import", "", cacheDir)
             inStream.copyTo(tempFile)
-            onImportData(tempFile) { tempFile.delete() }
+            onImportData(JavaUserFile(tempFile.toPath())) { tempFile.delete() }
         } catch (e: IOException) {
             activity.showMessage(activity.resources.getString(R.string.could_not_import))
             e.printStackTrace()
@@ -341,7 +342,7 @@ class ListHabitsScreen(
         }
     }
 
-    private fun onImportData(file: File, onFinished: () -> Unit) {
+    private fun onImportData(file: org.isoron.platform.io.UserFile, onFinished: () -> Unit) {
         taskRunner.execute(
             importTaskFactory.create(file) { result ->
                 when (result) {

uhabits-android/src/main/java/org/isoron/uhabits/inject/HabitsApplicationComponent.kt

@@ -21,7 +21,9 @@ package org.isoron.uhabits.inject
 import android.content.Context
 import me.tatarka.inject.annotations.Component
 import me.tatarka.inject.annotations.Provides
+import org.isoron.platform.io.AndroidFileOpener
 import org.isoron.platform.io.DatabaseOpener
+import org.isoron.platform.io.FileOpener
 import org.isoron.uhabits.core.AppScope
 import org.isoron.uhabits.core.commands.CommandRunner
 import org.isoron.uhabits.core.io.GenericImporter
@@ -136,4 +138,9 @@ abstract class HabitsApplicationComponent(
     @AppScope
     @Provides
     open fun taskRunner(): TaskRunner = AndroidTaskRunner()
+
+    @AppScope
+    @Provides
+    open fun fileOpener(): FileOpener =
+        AndroidFileOpener(appContext.assets, appContext.filesDir)
 }

uhabits-android/src/main/java/org/isoron/uhabits/tasks/ImportDataTask.kt

@@ -19,18 +19,19 @@
 package org.isoron.uhabits.tasks
 
 import android.util.Log
+import kotlinx.coroutines.runBlocking
+import org.isoron.platform.io.UserFile
 import org.isoron.platform.io.begin
 import org.isoron.platform.io.commit
 import org.isoron.uhabits.core.io.GenericImporter
 import org.isoron.uhabits.core.models.ModelFactory
 import org.isoron.uhabits.core.models.sqlite.SQLModelFactory
 import org.isoron.uhabits.core.tasks.Task
-import java.io.File
 
 class ImportDataTask(
     private val importer: GenericImporter,
     modelFactory: ModelFactory,
-    private val file: File,
+    private val file: UserFile,
     private val listener: Listener
 ) : Task {
     private var result = 0
@@ -38,13 +39,15 @@ class ImportDataTask(
     override fun doInBackground() {
         modelFactory.database.begin()
         try {
-            if (importer.canHandle(file)) {
+            runBlocking {
-                importer.importHabitsFromFile(file)
+                if (importer.canHandle(file)) {
-                result = SUCCESS
+                    importer.importHabitsFromFile(file)
-                modelFactory.database.commit()
+                    result = SUCCESS
-            } else {
+                    modelFactory.database.commit()
-                result = NOT_RECOGNIZED
+                } else {
-                modelFactory.database.commit()
+                    result = NOT_RECOGNIZED
+                    modelFactory.database.commit()
+                }
             }
         } catch (e: Exception) {
             result = FAILED

uhabits-android/src/main/java/org/isoron/uhabits/tasks/ImportDataTaskFactory.kt

@@ -20,15 +20,15 @@
 package org.isoron.uhabits.tasks
 
 import me.tatarka.inject.annotations.Inject
+import org.isoron.platform.io.UserFile
 import org.isoron.uhabits.core.io.GenericImporter
 import org.isoron.uhabits.core.models.ModelFactory
-import java.io.File
 
 @Inject
 class ImportDataTaskFactory(
     private val importer: GenericImporter,
     private val modelFactory: ModelFactory
 ) {
-    fun create(file: File, listener: ImportDataTask.Listener) =
+    fun create(file: UserFile, listener: ImportDataTask.Listener) =
         ImportDataTask(importer, modelFactory, file, listener)
 }

uhabits-core/src/commonMain/kotlin/org/isoron/platform/io/Database.kt

@@ -106,7 +106,7 @@ inline fun <T> Database.querySingle(
     return result
 }
 
-fun Database.migrateTo(targetVersion: Int, loadMigrationSQL: (Int) -> String) {
+suspend fun Database.migrateTo(targetVersion: Int, loadMigrationSQL: suspend (Int) -> String) {
     val currentVersion = getVersion()
     if (currentVersion >= targetVersion) return
     for (v in (currentVersion + 1)..targetVersion) {

uhabits-core/src/commonMain/kotlin/org/isoron/platform/io/Files.kt

@@ -52,6 +52,11 @@ interface FileOpener {
  * result of some user action, such as databases and logs.
  */
 interface UserFile {
+    /**
+     * The resolved absolute path string.
+     */
+    val pathString: String
+
     /**
      * Deletes the user file. If the file does not exist, nothing happens.
      */
@@ -67,6 +72,21 @@ interface UserFile {
      * exception.
      */
     suspend fun lines(): List<String>
+
+    /**
+     * Overwrites the file with [content], creating it if it doesn't exist.
+     */
+    suspend fun writeString(content: String)
+
+    /**
+     * Overwrites the file with [bytes], creating it if it doesn't exist.
+     */
+    suspend fun writeBytes(bytes: ByteArray)
+
+    /**
+     * Reads the first [limit] bytes from the file.
+     */
+    suspend fun readBytes(limit: Int): ByteArray
 }
 
 /**

uhabits-core/src/commonMain/kotlin/org/isoron/platform/io/Strings.kt

@@ -23,6 +23,40 @@ expect fun format(format: String, arg: String): String
 expect fun format(format: String, arg: Int): String
 expect fun format(format: String, arg: Double): String
 
+fun parseCsvLine(line: String): List<String> {
+    val result = mutableListOf<String>()
+    val sb = StringBuilder()
+    var inQuotes = false
+    var i = 0
+    while (i < line.length) {
+        val c = line[i]
+        if (inQuotes) {
+            if (c == '"') {
+                if (i + 1 < line.length && line[i + 1] == '"') {
+                    sb.append('"')
+                    i++
+                } else {
+                    inQuotes = false
+                }
+            } else {
+                sb.append(c)
+            }
+        } else {
+            when (c) {
+                ',' -> {
+                    result.add(sb.toString())
+                    sb.clear()
+                }
+                '"' -> inQuotes = true
+                else -> sb.append(c)
+            }
+        }
+        i++
+    }
+    result.add(sb.toString())
+    return result
+}
+
 fun csvLine(fields: Array<String>): String {
     return fields.joinToString(",") { field ->
         if (field.any { it == ',' || it == '"' || it == '\n' || it == '\r' }) {

uhabits-core/src/commonMain/kotlin/org/isoron/platform/io/ZipWriter.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2016-2025 Álinson Santos Xavier <git@axavier.org>
+ *
+ * This file is part of Loop Habit Tracker.
+ *
+ * Loop Habit Tracker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * Loop Habit Tracker is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.isoron.platform.io
+
+expect class ZipWriter() {
+    fun addEntry(name: String, content: String)
+    suspend fun toBytes(): ByteArray
+}

uhabits-core/src/commonTest/kotlin/org/isoron/platform/io/MigrationTest.kt

@@ -1,5 +1,6 @@
 package org.isoron.platform.io
 
+import kotlinx.coroutines.runBlocking
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
@@ -31,7 +32,7 @@ class MigrationTest {
     }
 
     @Test
-    fun testMigrateIdempotent() {
+    fun testMigrateIdempotent() = runBlocking {
         val db = TestDatabaseHelper.createEmptyDatabase()
         val version = db.getVersion()
         db.migrateTo(version) { v -> TestDatabaseHelper.loadMigrationSQL(v) }

uhabits-core/src/jvmMain/java/org/isoron/platform/io/JavaFiles.kt

@@ -66,6 +66,9 @@ class JavaResourceFile(val path: String) : ResourceFile {
 
 @Suppress("NewApi")
 class JavaUserFile(val path: Path) : UserFile {
+    override val pathString: String
+        get() = path.toString()
+
     override suspend fun lines(): List<String> {
         return Files.readAllLines(path)
     }
@@ -77,6 +80,25 @@ class JavaUserFile(val path: Path) : UserFile {
     override suspend fun delete() {
         Files.delete(path)
     }
+
+    override suspend fun writeString(content: String) {
+        path.toFile().parentFile?.mkdirs()
+        Files.write(path, content.toByteArray())
+    }
+
+    override suspend fun writeBytes(bytes: ByteArray) {
+        path.toFile().parentFile?.mkdirs()
+        Files.write(path, bytes)
+    }
+
+    override suspend fun readBytes(limit: Int): ByteArray {
+        val file = path.toFile()
+        file.inputStream().use { stream ->
+            val buf = ByteArray(limit)
+            val n = stream.read(buf)
+            return if (n <= 0) ByteArray(0) else buf.copyOf(n)
+        }
+    }
 }
 
 @Suppress("NewApi")

uhabits-core/src/jvmMain/java/org/isoron/platform/io/ZipWriter.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2016-2025 Álinson Santos Xavier <git@axavier.org>
+ *
+ * This file is part of Loop Habit Tracker.
+ *
+ * Loop Habit Tracker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * Loop Habit Tracker is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.isoron.platform.io
+
+import java.io.ByteArrayOutputStream
+import java.util.zip.ZipEntry
+import java.util.zip.ZipOutputStream
+
+actual class ZipWriter {
+    private val baos = ByteArrayOutputStream()
+    private val zos = ZipOutputStream(baos)
+
+    actual fun addEntry(name: String, content: String) {
+        zos.putNextEntry(ZipEntry(name))
+        zos.write(content.toByteArray())
+        zos.closeEntry()
+    }
+
+    actual suspend fun toBytes(): ByteArray {
+        zos.close()
+        return baos.toByteArray()
+    }
+}

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/io/AbstractImporter.kt

@@ -18,9 +18,9 @@
  */
 package org.isoron.uhabits.core.io
 
-import java.io.File
+import org.isoron.platform.io.UserFile
 
 abstract class AbstractImporter {
-    abstract fun canHandle(file: File): Boolean
+    abstract suspend fun canHandle(file: UserFile): Boolean
-    abstract fun importHabitsFromFile(file: File)
+    abstract suspend fun importHabitsFromFile(file: UserFile)
 }

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/io/GenericImporter.kt

@@ -19,7 +19,7 @@
 package org.isoron.uhabits.core.io
 
 import me.tatarka.inject.annotations.Inject
-import java.io.File
+import org.isoron.platform.io.UserFile
 
 /**
  * A GenericImporter decides which implementation of AbstractImporter is able to
@@ -40,7 +40,7 @@ class GenericImporter(
         habitBullCSVImporter
     )
 
-    override fun canHandle(file: File): Boolean {
+    override suspend fun canHandle(file: UserFile): Boolean {
         for (importer in importers) {
             if (importer.canHandle(file)) {
                 return true
@@ -49,7 +49,7 @@ class GenericImporter(
         return false
     }
 
-    override fun importHabitsFromFile(file: File) {
+    override suspend fun importHabitsFromFile(file: UserFile) {
         for (importer in importers) {
             if (importer.canHandle(file)) {
                 importer.importHabitsFromFile(file)

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/io/HabitBullCSVImporter.kt

@@ -18,8 +18,9 @@
  */
 package org.isoron.uhabits.core.io
 
-import com.opencsv.CSVReader
 import me.tatarka.inject.annotations.Inject
+import org.isoron.platform.io.UserFile
+import org.isoron.platform.io.parseCsvLine
 import org.isoron.platform.time.LocalDate
 import org.isoron.uhabits.core.models.Entry
 import org.isoron.uhabits.core.models.Frequency
@@ -27,9 +28,6 @@ import org.isoron.uhabits.core.models.Habit
 import org.isoron.uhabits.core.models.HabitList
 import org.isoron.uhabits.core.models.HabitType
 import org.isoron.uhabits.core.models.ModelFactory
-import java.io.BufferedReader
-import java.io.File
-import java.io.FileReader
 
 /**
  * Class that imports data from HabitBull CSV files.
@@ -43,16 +41,22 @@ class HabitBullCSVImporter(
 
     private val logger = logging.getLogger("HabitBullCSVImporter")
 
-    override fun canHandle(file: File): Boolean {
+    override suspend fun canHandle(file: UserFile): Boolean {
-        val reader = BufferedReader(FileReader(file))
+        return try {
-        val line = reader.readLine()
+            val lines = file.lines()
-        return line.startsWith("HabitName,HabitDescription,HabitCategory")
+            if (lines.isEmpty()) return false
+            lines[0].startsWith("HabitName,HabitDescription,HabitCategory")
+        } catch (e: Exception) {
+            false
+        }
     }
 
-    override fun importHabitsFromFile(file: File) {
+    override suspend fun importHabitsFromFile(file: UserFile) {
-        val reader = CSVReader(FileReader(file))
+        val lines = file.lines()
         val map = HashMap<String, Habit>()
-        for (cols in reader) {
+        for (line in lines) {
+            val cols = parseCsvLine(line)
+            if (cols.size < 6) continue
             val name = cols[0]
             if (name == "HabitName") continue
             val description = cols[1]
@@ -61,13 +65,13 @@ class HabitBullCSVImporter(
             if (h == null) {
                 h = modelFactory.buildHabit()
                 h.name = name
-                h.description = description ?: ""
+                h.description = description
                 h.frequency = Frequency.DAILY
                 habitList.add(h)
                 map[name] = h
                 logger.info("Creating habit: $name")
             }
-            val notes = cols[5] ?: ""
+            val notes = cols[5]
             when (val value = parseInt(cols[4])) {
                 0 -> h.originalEntries.add(Entry(date, Entry.NO, notes))
                 1 -> h.originalEntries.add(Entry(date, Entry.YES_MANUAL, notes))
@@ -86,12 +90,10 @@ class HabitBullCSVImporter(
 
     private fun parseDate(rawValue: String): LocalDate {
         if (rawValue.contains("-")) {
-            // yyyy-MM-dd
             val parts = rawValue.split("-")
             return LocalDate(parts[0].toInt(), parts[1].toInt(), parts[2].toInt())
         }
         if (rawValue.contains("/")) {
-            // M/d/yyyy
             val parts = rawValue.split("/")
             return LocalDate(parts[2].toInt(), parts[0].toInt(), parts[1].toInt())
         }

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/io/HabitsCSVExporter.kt

@@ -18,61 +18,41 @@
  */
 package org.isoron.uhabits.core.io
 
-import com.opencsv.CSVWriter
+import org.isoron.platform.io.ZipWriter
+import org.isoron.platform.io.csvLine
+import org.isoron.platform.io.format
 import org.isoron.platform.time.LocalDate
 import org.isoron.platform.time.getToday
-import org.isoron.uhabits.core.models.Entry
 import org.isoron.uhabits.core.models.EntryList
 import org.isoron.uhabits.core.models.Habit
 import org.isoron.uhabits.core.models.HabitList
-import org.isoron.uhabits.core.models.Score
-import java.io.File
-import java.io.FileInputStream
-import java.io.FileOutputStream
-import java.io.FileWriter
-import java.io.IOException
-import java.io.Writer
-import java.util.LinkedList
-import java.util.Locale
-import java.util.zip.ZipEntry
-import java.util.zip.ZipOutputStream
 import kotlin.math.min
 
 /**
- * Class that exports the application data to CSV files.
+ * Class that exports the application data to CSV files inside a ZIP archive.
  */
 class HabitsCSVExporter(
     private val allHabits: HabitList,
-    private val selectedHabits: List<Habit>,
+    private val selectedHabits: List<Habit>
-    dir: File
 ) {
-    private val generatedDirs = LinkedList<String>()
-    private val generatedFilenames = LinkedList<String>()
-    private val exportDirName: String = dir.absolutePath + "/"
     private val delimiter = ","
 
-    fun writeArchive(): String {
+    suspend fun writeArchive(): ByteArray {
-        writeHabits()
+        val zip = ZipWriter()
-        val zipFilename = writeZipFile()
+        zip.addEntry("Habits.csv", allHabits.writeCSV())
-        cleanup()
+        for (h in selectedHabits) {
-        return zipFilename
+            val habitDirName = habitDirName(h)
+            zip.addEntry("${habitDirName}Scores.csv", writeScores(h))
+            zip.addEntry("${habitDirName}Checkmarks.csv", writeEntries(h.computedEntries))
+        }
+        zip.addEntry("Scores.csv", writeMultipleHabitsScores())
+        zip.addEntry("Checkmarks.csv", writeMultipleHabitsCheckmarks())
+        return zip.toBytes()
     }
 
-    private fun addFileToZip(zos: ZipOutputStream, filename: String) {
+    private fun habitDirName(h: Habit): String {
-        val fis = FileInputStream(File(exportDirName + filename))
+        val sane = sanitizeFilename(h.name)
-        val ze = ZipEntry(filename)
+        return format("%03d", allHabits.indexOf(h) + 1) + " " + sane.trim() + "/"
-        zos.putNextEntry(ze)
-        var length: Int
-        val bytes = ByteArray(1024)
-        while (fis.read(bytes).also { length = it } >= 0) zos.write(bytes, 0, length)
-        zos.closeEntry()
-        fis.close()
-    }
-
-    private fun cleanup() {
-        for (filename in generatedFilenames) File(exportDirName + filename).delete()
-        for (filename in generatedDirs) File(exportDirName + filename).delete()
-        File(exportDirName).delete()
     }
 
     private fun sanitizeFilename(name: String): String {
@@ -80,139 +60,75 @@ class HabitsCSVExporter(
         return s.substring(0, min(s.length, 100))
     }
 
-    private fun writeHabits() {
+    private fun writeScores(habit: Habit): String {
-        val filename = "Habits.csv"
+        val sb = StringBuilder()
-        File(exportDirName).mkdirs()
-        val out = FileWriter(exportDirName + filename)
-        generatedFilenames.add(filename)
-        allHabits.writeCSV(out)
-        out.close()
-        for (h in selectedHabits) {
-            val sane = sanitizeFilename(h.name)
-            var habitDirName = String.format(Locale.US, "%03d %s", allHabits.indexOf(h) + 1, sane)
-            habitDirName = habitDirName.trim() + "/"
-            File(exportDirName + habitDirName).mkdirs()
-            generatedDirs.add(habitDirName)
-            writeScores(habitDirName, h)
-            writeEntries(habitDirName, h.computedEntries)
-        }
-        writeMultipleHabits()
-    }
-
-    private fun writeScores(habitDirName: String, habit: Habit) {
-        val path = habitDirName + "Scores.csv"
-        val out = FileWriter(exportDirName + path)
-        generatedFilenames.add(path)
         val today = getToday()
         var oldest = today
         val known = habit.computedEntries.getKnown()
         if (known.isNotEmpty()) oldest = known[known.size - 1].date
-        val csv = CSVWriter(out)
+        sb.append(csvLine(arrayOf("Date", "Score")))
-        csv.writeNext(arrayOf("Date", "Score"), false)
         for (s in habit.scores.getByInterval(oldest, today)) {
-            val date = s.date.toCSVString()
+            sb.append(csvLine(arrayOf(s.date.toCSVString(), format("%.4f", s.value))))
-            val score = String.format(Locale.US, "%.4f", s.value)
-            csv.writeNext(arrayOf(date, score), false)
         }
-        csv.close()
+        return sb.toString()
-        out.close()
     }
 
-    private fun writeEntries(habitDirName: String, entries: EntryList) {
+    private fun writeEntries(entries: EntryList): String {
-        val filename = habitDirName + "Checkmarks.csv"
+        val sb = StringBuilder()
-        val out = FileWriter(exportDirName + filename)
+        sb.append(csvLine(arrayOf("Date", "Value", "Notes")))
-        generatedFilenames.add(filename)
-        val csv = CSVWriter(out)
-        csv.writeNext(arrayOf("Date", "Value", "Notes"), false)
         for (entry in entries.getKnown()) {
-            val date = entry.date.toCSVString()
+            sb.append(csvLine(arrayOf(entry.date.toCSVString(), entry.formattedValue, entry.notes)))
-            csv.writeNext(
-                arrayOf(
-                    date,
-                    entry.formattedValue,
-                    entry.notes
-                ),
-                false
-            )
         }
-        csv.close()
+        return sb.toString()
-        out.close()
     }
 
-    /**
+    private fun writeMultipleHabitsScores(): String {
-     * Writes a scores file and a checkmarks file containing scores and checkmarks of every habit.
+        val sb = StringBuilder()
-     * The first column corresponds to the date. Subsequent columns correspond to a habit.
+        writeMultipleHabitsHeader(sb)
-     * Habits are taken from the list of selected habits.
-     * Dates are determined from the oldest repetition date to the newest repetition date found in
-     * the list of habits.
-     */
-    private fun writeMultipleHabits() {
-        val scoresFileName = "Scores.csv"
-        val checksFileName = "Checkmarks.csv"
-        generatedFilenames.add(scoresFileName)
-        generatedFilenames.add(checksFileName)
-
-        val scoresWriter = FileWriter(exportDirName + scoresFileName)
-        val checksWriter = FileWriter(exportDirName + checksFileName)
-        writeMultipleHabitsHeader(scoresWriter)
-        writeMultipleHabitsHeader(checksWriter)
-
         val timeframe = getTimeframe()
         val oldest = timeframe[0]
         val newest = getToday()
-        val checkmarks: MutableList<ArrayList<Entry>> = ArrayList()
+        val scores = selectedHabits.map { ArrayList(it.scores.getByInterval(oldest, newest)) }
-        val scores: MutableList<ArrayList<Score>> = ArrayList()
-        for (habit in selectedHabits) {
-            checkmarks.add(ArrayList(habit.computedEntries.getByInterval(oldest, newest)))
-            scores.add(ArrayList(habit.scores.getByInterval(oldest, newest)))
-        }
-
         val days = oldest.daysUntil(newest)
         for (i in 0..days) {
             val date = newest.minus(i).toCSVString()
-            val sb = StringBuilder()
             sb.append(date).append(delimiter)
-            checksWriter.write(sb.toString())
-            scoresWriter.write(sb.toString())
             for (j in selectedHabits.indices) {
-                checksWriter.write(checkmarks[j][i].formattedValue)
+                val score = format("%.4f", scores[j][i].value)
-                checksWriter.write(delimiter)
+                sb.append(score).append(delimiter)
-                val score = String.format(Locale.US, "%.4f", scores[j][i].value)
-                scoresWriter.write(score)
-                scoresWriter.write(delimiter)
             }
-            checksWriter.write("\n")
+            sb.append("\n")
-            scoresWriter.write("\n")
         }
-        scoresWriter.close()
+        return sb.toString()
-        checksWriter.close()
     }
 
-    /**
+    private fun writeMultipleHabitsCheckmarks(): String {
-     * Writes the first row, containing header information, using the given writer.
+        val sb = StringBuilder()
-     * This consists of the date title and the names of the selected habits.
+        writeMultipleHabitsHeader(sb)
-     *
+        val timeframe = getTimeframe()
-     * @param out the writer to use
+        val oldest = timeframe[0]
-     * @throws IOException if there was a problem writing
+        val newest = getToday()
-     */
+        val checkmarks = selectedHabits.map { ArrayList(it.computedEntries.getByInterval(oldest, newest)) }
-    @Throws(IOException::class)
+        val days = oldest.daysUntil(newest)
-    private fun writeMultipleHabitsHeader(out: Writer) {
+        for (i in 0..days) {
-        out.write("Date$delimiter")
+            val date = newest.minus(i).toCSVString()
+            sb.append(date).append(delimiter)
+            for (j in selectedHabits.indices) {
+                sb.append(checkmarks[j][i].formattedValue).append(delimiter)
+            }
+            sb.append("\n")
+        }
+        return sb.toString()
+    }
+
+    private fun writeMultipleHabitsHeader(sb: StringBuilder) {
+        sb.append("Date$delimiter")
         for (habit in selectedHabits) {
-            out.write(habit.name)
+            sb.append(habit.name).append(delimiter)
-            out.write(delimiter)
         }
-        out.write("\n")
+        sb.append("\n")
     }
 
-    /**
-     * Gets the overall timeframe of the selected habits.
-     * The timeframe is an array containing the oldest timestamp among the habits and the
-     * newest timestamp among the habits.
-     * Both timestamps are in milliseconds.
-     *
-     * @return the timeframe containing the oldest timestamp and the newest timestamp
-     */
     private fun getTimeframe(): Array<LocalDate> {
         var oldest = LocalDate(1000000)
         var newest = LocalDate(0)
@@ -226,15 +142,4 @@ class HabitsCSVExporter(
         }
         return arrayOf(oldest, newest)
     }
-
-    private fun writeZipFile(): String {
-        val date = getToday().toCSVString()
-        val zipFilename = String.format("%s/Loop Habits CSV %s.zip", exportDirName, date)
-        val fos = FileOutputStream(zipFilename)
-        val zos = ZipOutputStream(fos)
-        for (filename in generatedFilenames) addFileToZip(zos, filename)
-        zos.close()
-        fos.close()
-        return zipFilename
-    }
 }

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/io/LoopDBImporter.kt

@@ -21,6 +21,8 @@ package org.isoron.uhabits.core.io
 import me.tatarka.inject.annotations.Inject
 import org.isoron.platform.io.Database
 import org.isoron.platform.io.DatabaseOpener
+import org.isoron.platform.io.FileOpener
+import org.isoron.platform.io.UserFile
 import org.isoron.platform.io.getVersion
 import org.isoron.platform.io.migrateTo
 import org.isoron.platform.io.query
@@ -37,7 +39,6 @@ import org.isoron.uhabits.core.models.HabitList
 import org.isoron.uhabits.core.models.ModelFactory
 import org.isoron.uhabits.core.models.sqlite.SQLiteHabitList
 import org.isoron.uhabits.core.utils.isSQLite3File
-import java.io.File
 
 /**
  * Class that imports data from database files exported by Loop Habit Tracker.
@@ -48,14 +49,15 @@ class LoopDBImporter(
     @AppScope val modelFactory: ModelFactory,
     @AppScope val opener: DatabaseOpener,
     @AppScope val runner: CommandRunner,
-    @AppScope logging: Logging
+    @AppScope logging: Logging,
+    @AppScope val fileOpener: FileOpener
 ) : AbstractImporter() {
 
     private val logger = logging.getLogger("LoopDBImporter")
 
-    override fun canHandle(file: File): Boolean {
+    override suspend fun canHandle(file: UserFile): Boolean {
-        if (!file.isSQLite3File()) return false
+        if (!isSQLite3File(file)) return false
-        val db = opener.open(file.absolutePath)
+        val db = opener.open(file.pathString)
         var canHandle = true
         val count = db.querySingle(
             "select count(*) from SQLITE_MASTER where name='Habits' or name='Repetitions'"
@@ -72,12 +74,11 @@ class LoopDBImporter(
         return canHandle
     }
 
-    override fun importHabitsFromFile(file: File) {
+    override suspend fun importHabitsFromFile(file: UserFile) {
-        val db = opener.open(file.absolutePath)
+        val db = opener.open(file.pathString)
         db.migrateTo(DATABASE_VERSION) { version ->
             val filename = "%02d.sql".format(version)
-            javaClass.getResourceAsStream("/migrations/$filename")!!
+            fileOpener.openResourceFile("migrations/$filename").lines().joinToString("\n")
-                .bufferedReader().readText()
         }
 
         val habitDataList = loadHabits(db)

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/io/RewireDBImporter.kt

@@ -21,6 +21,7 @@ package org.isoron.uhabits.core.io
 import me.tatarka.inject.annotations.Inject
 import org.isoron.platform.io.Database
 import org.isoron.platform.io.DatabaseOpener
+import org.isoron.platform.io.UserFile
 import org.isoron.platform.io.begin
 import org.isoron.platform.io.commit
 import org.isoron.platform.io.query
@@ -34,7 +35,6 @@ import org.isoron.uhabits.core.models.ModelFactory
 import org.isoron.uhabits.core.models.Reminder
 import org.isoron.uhabits.core.models.WeekdayList
 import org.isoron.uhabits.core.utils.isSQLite3File
-import java.io.File
 
 /**
  * Class that imports database files exported by Rewire.
@@ -46,9 +46,9 @@ class RewireDBImporter(
     private val opener: DatabaseOpener
 ) : AbstractImporter() {
 
-    override fun canHandle(file: File): Boolean {
+    override suspend fun canHandle(file: UserFile): Boolean {
-        if (!file.isSQLite3File()) return false
+        if (!isSQLite3File(file)) return false
-        val db = opener.open(file.absolutePath)
+        val db = opener.open(file.pathString)
         val count = db.querySingle(
             "select count(*) from SQLITE_MASTER where name='CHECKINS' or name='UNIT'"
         ) { it.getInt(0) }
@@ -56,8 +56,8 @@ class RewireDBImporter(
         return count == 2
     }
 
-    override fun importHabitsFromFile(file: File) {
+    override suspend fun importHabitsFromFile(file: UserFile) {
-        val db = opener.open(file.absolutePath)
+        val db = opener.open(file.pathString)
         db.begin()
         createHabits(db)
         db.commit()

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/io/TickmateDBImporter.kt

@@ -21,6 +21,7 @@ package org.isoron.uhabits.core.io
 import me.tatarka.inject.annotations.Inject
 import org.isoron.platform.io.Database
 import org.isoron.platform.io.DatabaseOpener
+import org.isoron.platform.io.UserFile
 import org.isoron.platform.io.begin
 import org.isoron.platform.io.commit
 import org.isoron.platform.io.query
@@ -32,7 +33,6 @@ import org.isoron.uhabits.core.models.Habit
 import org.isoron.uhabits.core.models.HabitList
 import org.isoron.uhabits.core.models.ModelFactory
 import org.isoron.uhabits.core.utils.isSQLite3File
-import java.io.File
 
 /**
  * Class that imports data from database files exported by Tickmate.
@@ -44,9 +44,9 @@ class TickmateDBImporter(
     private val opener: DatabaseOpener
 ) : AbstractImporter() {
 
-    override fun canHandle(file: File): Boolean {
+    override suspend fun canHandle(file: UserFile): Boolean {
-        if (!file.isSQLite3File()) return false
+        if (!isSQLite3File(file)) return false
-        val db = opener.open(file.absolutePath)
+        val db = opener.open(file.pathString)
         val count = db.querySingle(
             "select count(*) from SQLITE_MASTER where name='tracks' or name='track2groups'"
         ) { it.getInt(0) }
@@ -54,8 +54,8 @@ class TickmateDBImporter(
         return count == 2
     }
 
-    override fun importHabitsFromFile(file: File) {
+    override suspend fun importHabitsFromFile(file: UserFile) {
-        val db = opener.open(file.absolutePath)
+        val db = opener.open(file.pathString)
         db.begin()
         createHabits(db)
         db.commit()

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/models/HabitList.kt

@@ -20,14 +20,10 @@ package org.isoron.uhabits.core.models
 
 import org.isoron.platform.io.csvLine
 import org.isoron.platform.io.format
-import java.io.IOException
-import java.io.Writer
-import javax.annotation.concurrent.ThreadSafe
 
 /**
  * An ordered collection of [Habit]s.
  */
-@ThreadSafe
 abstract class HabitList : Iterable<Habit> {
     val observable: ModelObservable
 
@@ -168,16 +164,12 @@ abstract class HabitList : Iterable<Habit> {
     }
 
     /**
-     * Writes the list of habits to the given writer, in CSV format. There is
+     * Returns the list of habits in CSV format. There is one line for each
-     * one line for each habit, containing the fields name, description,
+     * habit, containing the fields name, description, frequency numerator,
-     * frequency numerator, frequency denominator and color. The color is
+     * frequency denominator and color.
-     * written in HTML format (#000000).
-     *
-     * @param out the writer that will receive the result
-     * @throws IOException if write operations fail
      */
-    @Throws(IOException::class)
+    fun writeCSV(): String {
-    fun writeCSV(out: Writer) {
+        val sb = StringBuilder()
         val header = arrayOf(
             "Position",
             "Name",
@@ -192,7 +184,7 @@ abstract class HabitList : Iterable<Habit> {
             "Target Value",
             "Archived?"
         )
-        out.write(csvLine(header))
+        sb.append(csvLine(header))
         for (habit in this) {
             val (numerator, denominator) = habit.frequency
             val cols = arrayOf(
@@ -209,9 +201,9 @@ abstract class HabitList : Iterable<Habit> {
                 if (habit.isNumerical) habit.targetValue.toString() else "",
                 habit.isArchived.toString()
             )
-            out.write(csvLine(cols))
+            sb.append(csvLine(cols))
         }
-        out.close()
+        return sb.toString()
     }
 
     abstract fun resort()

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/models/StreakList.kt

@@ -19,10 +19,8 @@
 package org.isoron.uhabits.core.models
 
 import org.isoron.platform.time.LocalDate
-import javax.annotation.concurrent.ThreadSafe
 import kotlin.math.min
 
-@ThreadSafe
 class StreakList {
     private val list = ArrayList<Streak>()
 

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/preferences/MemoryStorage.kt

@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2016-2025 Álinson Santos Xavier <git@axavier.org>
+ *
+ * This file is part of Loop Habit Tracker.
+ *
+ * Loop Habit Tracker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * Loop Habit Tracker is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.isoron.uhabits.core.preferences
+
+class MemoryStorage : Preferences.Storage {
+    private val map = HashMap<String, String>()
+
+    override fun clear() {
+        map.clear()
+    }
+
+    override fun getBoolean(key: String, defValue: Boolean): Boolean =
+        map[key]?.toBoolean() ?: defValue
+
+    override fun getInt(key: String, defValue: Int): Int =
+        map[key]?.toIntOrNull() ?: defValue
+
+    override fun getLong(key: String, defValue: Long): Long =
+        map[key]?.toLongOrNull() ?: defValue
+
+    override fun getString(key: String, defValue: String): String =
+        map[key] ?: defValue
+
+    override fun onAttached(preferences: Preferences) {}
+
+    override fun putBoolean(key: String, value: Boolean) {
+        map[key] = value.toString()
+    }
+
+    override fun putInt(key: String, value: Int) {
+        map[key] = value.toString()
+    }
+
+    override fun putLong(key: String, value: Long) {
+        map[key] = value.toString()
+    }
+
+    override fun putString(key: String, value: String) {
+        map[key] = value
+    }
+
+    override fun remove(key: String) {
+        map.remove(key)
+    }
+}

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/preferences/PropertiesStorage.kt

@@ -1,99 +0,0 @@
-/*
- * Copyright (C) 2016-2025 Álinson Santos Xavier <git@axavier.org>
- *
- * This file is part of Loop Habit Tracker.
- *
- * Loop Habit Tracker is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by the
- * Free Software Foundation, either version 3 of the License, or (at your
- * option) any later version.
- *
- * Loop Habit Tracker is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
- * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-package org.isoron.uhabits.core.preferences
-
-import java.io.File
-import java.io.FileInputStream
-import java.io.FileOutputStream
-import java.io.IOException
-import java.util.Properties
-
-class PropertiesStorage(file: File) : Preferences.Storage {
-    private var props: Properties
-    private val file: File
-    override fun clear() {
-        for (key in props.stringPropertyNames()) props.remove(key)
-        flush()
-    }
-
-    override fun getBoolean(key: String, defValue: Boolean): Boolean {
-        val value = props.getProperty(key, java.lang.Boolean.toString(defValue))
-        return java.lang.Boolean.parseBoolean(value)
-    }
-
-    override fun getInt(key: String, defValue: Int): Int {
-        val value = props.getProperty(key, defValue.toString())
-        return value.toInt()
-    }
-
-    override fun getLong(key: String, defValue: Long): Long {
-        val value = props.getProperty(key, defValue.toString())
-        return value.toLong()
-    }
-
-    override fun getString(key: String, defValue: String): String {
-        return props.getProperty(key, defValue)
-    }
-
-    override fun onAttached(preferences: Preferences) {
-        // nop
-    }
-
-    override fun putBoolean(key: String, value: Boolean) {
-        props.setProperty(key, java.lang.Boolean.toString(value))
-    }
-
-    override fun putInt(key: String, value: Int) {
-        props.setProperty(key, value.toString())
-        flush()
-    }
-
-    private fun flush() {
-        try {
-            props.store(FileOutputStream(file), "")
-        } catch (e: IOException) {
-            throw RuntimeException(e)
-        }
-    }
-
-    override fun putLong(key: String, value: Long) {
-        props.setProperty(key, value.toString())
-        flush()
-    }
-
-    override fun putString(key: String, value: String) {
-        props.setProperty(key, value)
-        flush()
-    }
-
-    override fun remove(key: String) {
-        props.remove(key)
-        flush()
-    }
-
-    init {
-        try {
-            this.file = file
-            props = Properties()
-            props.load(FileInputStream(file))
-        } catch (e: IOException) {
-            throw RuntimeException(e)
-        }
-    }
-}

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/tasks/ExportCSVTask.kt

@@ -18,6 +18,8 @@
  */
 package org.isoron.uhabits.core.tasks
 
+import kotlinx.coroutines.runBlocking
+import org.isoron.platform.time.getToday
 import org.isoron.uhabits.core.io.HabitsCSVExporter
 import org.isoron.uhabits.core.models.Habit
 import org.isoron.uhabits.core.models.HabitList
@@ -26,14 +28,20 @@ import java.io.File
 class ExportCSVTask(
     private val habitList: HabitList,
     private val selectedHabits: List<Habit>,
-    private val outputDir: File,
+    private val outputDir: String,
     private val listener: Listener
 ) : Task {
     private var archiveFilename: String? = null
     override fun doInBackground() {
         try {
-            val exporter = HabitsCSVExporter(habitList, selectedHabits, outputDir)
+            val exporter = HabitsCSVExporter(habitList, selectedHabits)
-            archiveFilename = exporter.writeArchive()
+            val bytes = runBlocking { exporter.writeArchive() }
+            val date = getToday().toCSVString()
+            val dir = File(outputDir)
+            dir.mkdirs()
+            val zipFile = File(dir, "Loop Habits CSV $date.zip")
+            zipFile.writeBytes(bytes)
+            archiveFilename = zipFile.absolutePath
         } catch (e: Exception) {
             e.printStackTrace()
         }

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/tasks/ExportCSVTaskFactory.kt

@@ -22,7 +22,6 @@ package org.isoron.uhabits.core.tasks
 import me.tatarka.inject.annotations.Inject
 import org.isoron.uhabits.core.models.Habit
 import org.isoron.uhabits.core.models.HabitList
-import java.io.File
 
 @Inject
 class ExportCSVTaskFactory(
@@ -30,7 +29,7 @@ class ExportCSVTaskFactory(
 ) {
     fun create(
         selectedHabits: List<Habit>,
-        outputDir: File,
+        outputDir: String,
         listener: ExportCSVTask.Listener
     ) = ExportCSVTask(habitList, selectedHabits, outputDir, listener)
 }

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsBehavior.kt

@@ -33,9 +33,6 @@ import org.isoron.uhabits.core.models.PaletteColor
 import org.isoron.uhabits.core.preferences.Preferences
 import org.isoron.uhabits.core.tasks.ExportCSVTask
 import org.isoron.uhabits.core.tasks.TaskRunner
-import java.io.File
-import java.io.IOException
-import java.util.LinkedList
 import kotlin.math.roundToInt
 
 @Inject
@@ -81,8 +78,7 @@ open class ListHabitsBehavior(
     }
 
     fun onExportCSV() {
-        val selected: MutableList<Habit> = LinkedList()
+        val selected = habitList.toList()
-        for (h in habitList) selected.add(h)
         val outputDir = dirFinder.getCSVOutputDir()
         taskRunner.execute(
             ExportCSVTask(habitList, selected, outputDir) { filename: String? ->
@@ -119,7 +115,7 @@ open class ListHabitsBehavior(
         try {
             val log = bugReporter.getBugReport()
             screen.showSendBugReportToDeveloperScreen(log)
-        } catch (e: IOException) {
+        } catch (e: Exception) {
             e.printStackTrace()
             screen.showMessage(Message.COULD_NOT_GENERATE_BUG_REPORT)
         }
@@ -149,12 +145,11 @@ open class ListHabitsBehavior(
     interface BugReporter {
         fun dumpBugReportToFile()
 
-        @Throws(IOException::class)
         fun getBugReport(): String
     }
 
     interface DirFinder {
-        fun getCSVOutputDir(): File
+        fun getCSVOutputDir(): String
     }
 
     fun interface NumberPickerCallback {

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/ui/screens/habits/show/ShowHabitMenuPresenter.kt

@@ -29,7 +29,6 @@ import org.isoron.uhabits.core.models.HabitList
 import org.isoron.uhabits.core.tasks.ExportCSVTask
 import org.isoron.uhabits.core.tasks.TaskRunner
 import org.isoron.uhabits.core.ui.callbacks.OnConfirmedCallback
-import java.io.File
 import kotlin.math.PI
 import kotlin.math.cos
 import kotlin.math.ln
@@ -127,6 +126,6 @@ class ShowHabitMenuPresenter(
     }
 
     interface System {
-        fun getCSVOutputDir(): File
+        fun getCSVOutputDir(): String
     }
 }

uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/utils/FileExtensions.kt

@@ -19,13 +19,10 @@
 
 package org.isoron.uhabits.core.utils
 
-import java.io.File
+import org.isoron.platform.io.UserFile
-import java.io.FileInputStream
 
-fun File.isSQLite3File(): Boolean {
+suspend fun isSQLite3File(file: UserFile): Boolean {
-    val fis = FileInputStream(this)
+    if (!file.exists()) return false
-    val sqliteHeader = "SQLite format 3".toByteArray()
+    val header = file.readBytes(16)
-    val buffer = ByteArray(sqliteHeader.size)
+    return header.decodeToString().startsWith("SQLite format 3")
-    val count = fis.read(buffer)
-    return if (count < sqliteHeader.size) false else buffer.contentEquals(sqliteHeader)
 }

uhabits-core/src/jvmTest/java/org/isoron/platform/io/JavaFilesTest.kt

@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2016-2025 Álinson Santos Xavier <git@axavier.org>
+ *
+ * This file is part of Loop Habit Tracker.
+ *
+ * Loop Habit Tracker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * Loop Habit Tracker is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.isoron.platform.io
+
+import kotlinx.coroutines.runBlocking
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class JavaFilesTest {
+
+    @Test
+    fun testWriteStringAndLines() = runBlocking {
+        val file = JavaUserFile(kotlin.io.path.createTempFile("test", ".txt"))
+        file.writeString("hello\nworld\n")
+        val lines = file.lines()
+        assertEquals(listOf("hello", "world"), lines)
+        file.delete()
+    }
+
+    @Test
+    fun testWriteBytesAndReadBytes() = runBlocking {
+        val file = JavaUserFile(kotlin.io.path.createTempFile("test", ".bin"))
+        val data = byteArrayOf(0x53, 0x51, 0x4C, 0x69, 0x74, 0x65)
+        file.writeBytes(data)
+        val read = file.readBytes(6)
+        assertTrue(data.contentEquals(read))
+        file.delete()
+    }
+
+    @Test
+    fun testReadBytesWithLimit() = runBlocking {
+        val file = JavaUserFile(kotlin.io.path.createTempFile("test", ".bin"))
+        file.writeBytes(byteArrayOf(1, 2, 3, 4, 5, 6, 7, 8))
+        val read = file.readBytes(3)
+        assertEquals(3, read.size)
+        assertEquals(1, read[0])
+        assertEquals(2, read[1])
+        assertEquals(3, read[2])
+        file.delete()
+    }
+
+    @Test
+    fun testPath() = runBlocking {
+        val tmpPath = kotlin.io.path.createTempFile("test", ".txt")
+        val file = JavaUserFile(tmpPath)
+        assertEquals(tmpPath.toString(), file.pathString)
+        file.delete()
+    }
+
+    @Test
+    fun testExists() = runBlocking {
+        val file = JavaUserFile(kotlin.io.path.createTempFile("test", ".txt"))
+        assertTrue(file.exists())
+        file.delete()
+        assertFalse(file.exists())
+    }
+}

uhabits-core/src/jvmTest/java/org/isoron/platform/io/StringsTest.kt

@@ -34,4 +34,15 @@ class StringsTest {
         assertEquals("00013.42", format("%08.2f", 13.419187263))
         assertEquals("13.42   ", format("%-8.2f", 13.419187263))
     }
+
+    @Test
+    fun testParseCsvLine() {
+        assertEquals(listOf("a", "b", "c"), parseCsvLine("a,b,c"))
+        assertEquals(listOf("hello world", "foo", "bar"), parseCsvLine("hello world,foo,bar"))
+        assertEquals(listOf("has,comma", "normal"), parseCsvLine("\"has,comma\",normal"))
+        assertEquals(listOf("has\"quote", "x"), parseCsvLine("\"has\"\"quote\",x"))
+        assertEquals(listOf("", "", ""), parseCsvLine(",,"))
+        assertEquals(listOf("single"), parseCsvLine("single"))
+        assertEquals(listOf("a", "line\nbreak", "b"), parseCsvLine("a,\"line\nbreak\",b"))
+    }
 }

uhabits-core/src/jvmTest/java/org/isoron/platform/io/TestDatabaseHelper.kt

@@ -1,19 +1,24 @@
 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 {
         val db = JavaDatabaseOpener().open(":memory:")
         db.setVersion(8)
-        db.migrateTo(DATABASE_VERSION) { v -> loadMigrationSQL(v) }
+        runBlocking {
+            db.migrateTo(DATABASE_VERSION) { v -> loadMigrationSQL(v) }
+        }
         return db
     }
 
     actual fun loadMigrationSQL(version: Int): String {
-        val filename = "/migrations/%02d.sql".format(version)
+        val path = "migrations/%02d.sql".format(version)
-        return TestDatabaseHelper::class.java
+        return runBlocking {
-            .getResourceAsStream(filename)!!
+            fileOpener.openResourceFile(path).lines().joinToString("\n")
-            .bufferedReader().readText()
+        }
     }
 }

uhabits-core/src/jvmTest/java/org/isoron/platform/io/ZipWriterTest.kt

@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2016-2025 Álinson Santos Xavier <git@axavier.org>
+ *
+ * This file is part of Loop Habit Tracker.
+ *
+ * Loop Habit Tracker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * Loop Habit Tracker is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.isoron.platform.io
+
+import kotlinx.coroutines.runBlocking
+import java.io.ByteArrayInputStream
+import java.util.zip.ZipInputStream
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class ZipWriterTest {
+
+    @Test
+    fun testSingleEntry() = runBlocking {
+        val zip = ZipWriter()
+        zip.addEntry("hello.txt", "Hello, World!")
+        val bytes = zip.toBytes()
+
+        val entries = readZipEntries(bytes)
+        assertEquals(1, entries.size)
+        assertEquals("Hello, World!", entries["hello.txt"])
+    }
+
+    @Test
+    fun testMultipleEntries() = runBlocking {
+        val zip = ZipWriter()
+        zip.addEntry("a.csv", "name,value\nfoo,1\n")
+        zip.addEntry("subdir/b.csv", "col1,col2\nbar,2\n")
+        zip.addEntry("subdir/c.csv", "x\n")
+        val bytes = zip.toBytes()
+
+        val entries = readZipEntries(bytes)
+        assertEquals(3, entries.size)
+        assertEquals("name,value\nfoo,1\n", entries["a.csv"])
+        assertEquals("col1,col2\nbar,2\n", entries["subdir/b.csv"])
+        assertEquals("x\n", entries["subdir/c.csv"])
+    }
+
+    @Test
+    fun testEmptyContent() = runBlocking {
+        val zip = ZipWriter()
+        zip.addEntry("empty.txt", "")
+        val bytes = zip.toBytes()
+
+        val entries = readZipEntries(bytes)
+        assertEquals(1, entries.size)
+        assertEquals("", entries["empty.txt"])
+    }
+
+    @Test
+    fun testLargeContent() = runBlocking {
+        val zip = ZipWriter()
+        val large = "x".repeat(100_000)
+        zip.addEntry("large.txt", large)
+        val bytes = zip.toBytes()
+
+        assertTrue(bytes.size < large.length, "ZIP should compress repeated content")
+        val entries = readZipEntries(bytes)
+        assertEquals(large, entries["large.txt"])
+    }
+
+    private fun readZipEntries(bytes: ByteArray): Map<String, String> {
+        val result = mutableMapOf<String, String>()
+        val zis = ZipInputStream(ByteArrayInputStream(bytes))
+        var entry = zis.nextEntry
+        while (entry != null) {
+            result[entry.name] = zis.readBytes().decodeToString()
+            zis.closeEntry()
+            entry = zis.nextEntry
+        }
+        zis.close()
+        return result
+    }
+}

uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/database/migrations/Version22Test.kt

@@ -18,10 +18,12 @@
  */
 package org.isoron.uhabits.core.database.migrations
 
+import kotlinx.coroutines.runBlocking
 import org.hamcrest.MatcherAssert.assertThat
 import org.hamcrest.Matchers
 import org.hamcrest.Matchers.equalTo
 import org.isoron.platform.io.Database
+import org.isoron.platform.io.JavaFileOpener
 import org.isoron.platform.io.migrateTo
 import org.isoron.platform.io.querySingle
 import org.isoron.platform.io.run
@@ -38,11 +40,12 @@ class Version22Test : BaseUnitTest() {
         db = openDatabaseResource("/databases/021.db")
     }
 
-    private fun migrateTo(version: Int) {
+    private val fileOpener = JavaFileOpener()
+
+    private fun migrateTo(version: Int) = runBlocking {
         db.migrateTo(version) { v ->
-            val filename = "%02d.sql".format(v)
+            val path = "migrations/%02d.sql".format(v)
-            javaClass.getResourceAsStream("/migrations/$filename")!!
+            fileOpener.openResourceFile(path).lines().joinToString("\n")
-                .bufferedReader().readText()
         }
     }
 

uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/database/migrations/Version23Test.kt

@@ -19,9 +19,11 @@
 
 package org.isoron.uhabits.core.database.migrations
 
+import kotlinx.coroutines.runBlocking
 import org.hamcrest.CoreMatchers.equalTo
 import org.hamcrest.MatcherAssert.assertThat
 import org.isoron.platform.io.Database
+import org.isoron.platform.io.JavaFileOpener
 import org.isoron.platform.io.migrateTo
 import org.isoron.platform.io.query
 import org.isoron.uhabits.core.BaseUnitTest
@@ -36,11 +38,12 @@ class Version23Test : BaseUnitTest() {
         db = openDatabaseResource("/databases/022.db")
     }
 
-    private fun migrateTo(version: Int) {
+    private val fileOpener = JavaFileOpener()
+
+    private fun migrateTo(version: Int) = runBlocking {
         db.migrateTo(version) { v ->
-            val filename = "%02d.sql".format(v)
+            val path = "migrations/%02d.sql".format(v)
-            javaClass.getResourceAsStream("/migrations/$filename")!!
+            fileOpener.openResourceFile(path).lines().joinToString("\n")
-                .bufferedReader().readText()
         }
     }
 

uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/io/HabitsCSVExporterTest.kt

@@ -18,17 +18,17 @@
  */
 package org.isoron.uhabits.core.io
 
-import org.apache.commons.io.IOUtils
+import kotlinx.coroutines.runBlocking
 import org.isoron.uhabits.core.BaseUnitTest
 import org.isoron.uhabits.core.models.Habit
 import org.junit.Before
 import org.junit.Test
+import java.io.ByteArrayInputStream
 import java.io.File
-import java.io.FileOutputStream
 import java.io.IOException
 import java.nio.file.Files
 import java.util.*
-import java.util.zip.ZipFile
+import java.util.zip.ZipInputStream
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
 
@@ -47,18 +47,16 @@ class HabitsCSVExporterTest : BaseUnitTest() {
 
     @Test
     @Throws(IOException::class)
-    fun testExportCSV() {
+    fun testExportCSV() = runBlocking {
         val selected: MutableList<Habit> = LinkedList()
         for (h in habitList) selected.add(h)
-        val exporter = HabitsCSVExporter(
+        val exporter = HabitsCSVExporter(habitList, selected)
-            habitList,
+        val bytes = exporter.writeArchive()
-            selected,
+        assertTrue(bytes.isNotEmpty())
-            baseDir
+
-        )
+        // Extract zip entries to baseDir for comparison
-        val filename = exporter.writeArchive()
+        unzip(bytes)
-        assertAbsolutePathExists(filename)
+
-        val archive = File(filename)
-        unzip(archive)
         val filesToCheck = arrayOf(
             "001 Meditate/Checkmarks.csv",
             "001 Meditate/Scores.csv",
@@ -75,32 +73,21 @@ class HabitsCSVExporterTest : BaseUnitTest() {
         }
     }
 
-    @Throws(IOException::class)
+    private fun unzip(bytes: ByteArray) {
-    private fun unzip(file: File) {
+        val zis = ZipInputStream(ByteArrayInputStream(bytes))
-        val zip = ZipFile(file)
+        var entry = zis.nextEntry
-        val e = zip.entries()
+        while (entry != null) {
-        while (e.hasMoreElements()) {
+            val outFile = File(baseDir, entry.name)
-            val entry = e.nextElement()
+            outFile.parentFile?.mkdirs()
-            val stream = zip.getInputStream(entry)
+            outFile.writeBytes(zis.readBytes())
-            val outputFilename = String.format(
+            zis.closeEntry()
-                "%s/%s",
+            entry = zis.nextEntry
-                baseDir.absolutePath,
-                entry.name
-            )
-            val out = File(outputFilename)
-            val parent = out.parentFile
-            parent?.mkdirs()
-            IOUtils.copy(stream, FileOutputStream(out))
         }
-        zip.close()
+        zis.close()
     }
 
     private fun assertPathExists(s: String) {
-        assertAbsolutePathExists(String.format("%s/%s", baseDir.absolutePath, s))
+        val file = File(baseDir, s)
-    }
-
-    private fun assertAbsolutePathExists(s: String) {
-        val file = File(s)
         assertTrue(
             String.format("File %s should exist", file.absolutePath)
         ) { file.exists() }
@@ -108,7 +95,7 @@ class HabitsCSVExporterTest : BaseUnitTest() {
 
     private fun assertFileAndReferenceAreEqual(s: String) {
         val assetFilename = String.format("csv_export/%s", s)
-        val actualFile = File(String.format("%s/%s", baseDir.absolutePath, s))
+        val actualFile = File(baseDir, s)
         val expectedFile = File.createTempFile("asset", "")
         expectedFile.deleteOnExit()
         copyAssetToFile(assetFilename, expectedFile)

uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/io/ImportTest.kt

@@ -18,8 +18,11 @@
  */
 package org.isoron.uhabits.core.io
 
+import kotlinx.coroutines.runBlocking
 import org.hamcrest.MatcherAssert.assertThat
 import org.hamcrest.core.IsEqual.equalTo
+import org.isoron.platform.io.JavaFileOpener
+import org.isoron.platform.io.JavaUserFile
 import org.isoron.platform.time.LocalDate
 import org.isoron.uhabits.core.BaseUnitTest
 import org.isoron.uhabits.core.models.Entry
@@ -173,25 +176,27 @@ class ImportTest : BaseUnitTest() {
     }
 
     @Throws(IOException::class)
-    private fun importFromFile(assetFilename: String) {
+    private fun importFromFile(assetFilename: String) = runBlocking {
         val file = File.createTempFile("asset", "")
         copyAssetToFile(assetFilename, file)
         assertTrue(file.exists())
         assertTrue(file.canRead())
+        val userFile = JavaUserFile(file.toPath())
         val importer = GenericImporter(
             LoopDBImporter(
                 habitList,
                 modelFactory,
                 databaseOpener,
                 commandRunner,
-                StandardLogging()
+                StandardLogging(),
+                JavaFileOpener()
             ),
             RewireDBImporter(habitList, modelFactory, databaseOpener),
             TickmateDBImporter(habitList, modelFactory, databaseOpener),
             HabitBullCSVImporter(habitList, modelFactory, StandardLogging())
         )
-        assertTrue(importer.canHandle(file))
+        assertTrue(importer.canHandle(userFile))
-        importer.importHabitsFromFile(file)
+        importer.importHabitsFromFile(userFile)
         file.delete()
     }
 }

uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/models/HabitListTest.kt

@@ -25,7 +25,6 @@ import org.isoron.uhabits.core.BaseUnitTest
 import org.junit.Assert.assertThrows
 import org.junit.Test
 import java.io.IOException
-import java.io.StringWriter
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
 import kotlin.test.assertNull
@@ -214,9 +213,7 @@ class HabitListTest : BaseUnitTest() {
             003,Wake up early,YES_NO,Did you wake up before 6am?,,2,3,#AFB42B,,,,false
             
             """.trimIndent()
-        val writer = StringWriter()
+        assertThat(list.writeCSV(), equalTo(expectedCSV))
-        list.writeCSV(writer)
-        assertThat(writer.toString(), equalTo(expectedCSV))
     }
 
     @Test

uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/preferences/PreferencesTest.kt

@@ -27,7 +27,6 @@ import org.isoron.uhabits.core.ui.ThemeSwitcher
 import org.junit.Before
 import org.junit.Test
 import org.mockito.kotlin.mock
-import java.io.File
 import kotlin.test.assertFalse
 import kotlin.test.assertNull
 import kotlin.test.assertTrue
@@ -36,15 +35,13 @@ class PreferencesTest : BaseUnitTest() {
     private lateinit var prefs: Preferences
 
     private var listener: Preferences.Listener = mock()
-    private lateinit var storage: PropertiesStorage
+    private lateinit var storage: MemoryStorage
 
     @Before
     @Throws(Exception::class)
     override fun setUp() {
         super.setUp()
-        val file = File.createTempFile("prefs", ".properties")
+        storage = MemoryStorage()
-        file.deleteOnExit()
-        storage = PropertiesStorage(file)
         prefs = Preferences(storage)
         prefs.addListener(listener)
     }

uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/preferences/PropertiesStorageTest.kt

@@ -1,102 +0,0 @@
-/*
- * Copyright (C) 2016-2025 Álinson Santos Xavier <git@axavier.org>
- *
- * This file is part of Loop Habit Tracker.
- *
- * Loop Habit Tracker is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by the
- * Free Software Foundation, either version 3 of the License, or (at your
- * option) any later version.
- *
- * Loop Habit Tracker is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
- * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-package org.isoron.uhabits.core.preferences
-
-import org.hamcrest.CoreMatchers.equalTo
-import org.hamcrest.MatcherAssert.assertThat
-import org.isoron.uhabits.core.BaseUnitTest
-import org.junit.Before
-import org.junit.Test
-import java.io.File
-import java.util.Arrays
-import kotlin.test.assertEquals
-import kotlin.test.assertFalse
-import kotlin.test.assertTrue
-
-class PropertiesStorageTest : BaseUnitTest() {
-    private lateinit var storage: PropertiesStorage
-    private lateinit var file: File
-
-    @Before
-    @Throws(Exception::class)
-    override fun setUp() {
-        super.setUp()
-        file = File.createTempFile("test", ".properties")
-        file.deleteOnExit()
-        storage = PropertiesStorage(file)
-    }
-
-    @Test
-    @Throws(Exception::class)
-    fun testPutGetRemove() {
-        storage.putBoolean("booleanKey", true)
-        assertTrue(storage.getBoolean("booleanKey", false))
-        assertFalse(storage.getBoolean("random", false))
-        storage.putInt("intKey", 64)
-        assertThat(storage.getInt("intKey", 200), equalTo(64))
-        assertThat(storage.getInt("random", 200), equalTo(200))
-        storage.putLong("longKey", 64L)
-        assertThat(storage.getLong("intKey", 200L), equalTo(64L))
-        assertThat(storage.getLong("random", 200L), equalTo(200L))
-        storage.putString("stringKey", "Hello")
-        assertThat(storage.getString("stringKey", ""), equalTo("Hello"))
-        assertThat(storage.getString("random", ""), equalTo(""))
-        storage.remove("stringKey")
-        assertThat(storage.getString("stringKey", ""), equalTo(""))
-        storage.clear()
-        assertThat(storage.getLong("intKey", 200L), equalTo(200L))
-        assertFalse(storage.getBoolean("booleanKey", false))
-    }
-
-    @Test
-    @Throws(Exception::class)
-    fun testPersistence() {
-        storage.putBoolean("booleanKey", true)
-        storage.putInt("intKey", 64)
-        storage.putLong("longKey", 64L)
-        storage.putString("stringKey", "Hello")
-        val storage2 = PropertiesStorage(file)
-        assertTrue(storage2.getBoolean("booleanKey", false))
-        assertThat(storage2.getInt("intKey", 200), equalTo(64))
-        assertThat(storage2.getLong("intKey", 200L), equalTo(64L))
-        assertThat(storage2.getString("stringKey", ""), equalTo("Hello"))
-    }
-
-    @Test
-    @Throws(Exception::class)
-    fun testLongArray() {
-        val expected1 = longArrayOf(1L, 2L, 3L, 5L)
-        val expected2 = longArrayOf(1L)
-        val expected3 = longArrayOf()
-        val expected4 = longArrayOf()
-        storage.putLongArray("key1", expected1)
-        storage.putLongArray("key2", expected2)
-        storage.putLongArray("key3", expected3)
-        val actual1 = storage.getLongArray("key1", longArrayOf())
-        val actual2 = storage.getLongArray("key2", longArrayOf())
-        val actual3 = storage.getLongArray("key3", longArrayOf())
-        val actual4 = storage.getLongArray("invalidKey", longArrayOf())
-        assertTrue(Arrays.equals(actual1, expected1))
-        assertTrue(Arrays.equals(actual2, expected2))
-        assertTrue(Arrays.equals(actual3, expected3))
-        assertTrue(Arrays.equals(actual4, expected4))
-        assertEquals("1,2,3,5", storage.getString("key1", ""))
-        assertEquals(1, storage.getLong("key2", -1))
-    }
-}

uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsBehaviorTest.kt

@@ -36,7 +36,6 @@ import org.mockito.kotlin.eq
 import org.mockito.kotlin.mock
 import org.mockito.kotlin.verify
 import org.mockito.kotlin.whenever
-import java.io.IOException
 import java.nio.file.Files
 import kotlin.test.assertFalse
 import kotlin.test.assertTrue
@@ -92,7 +91,7 @@ class ListHabitsBehaviorTest : BaseUnitTest() {
     @Throws(Exception::class)
     fun testOnExportCSV() {
         val outputDir = Files.createTempDirectory("CSV").toFile()
-        whenever(dirFinder.getCSVOutputDir()).thenReturn(outputDir)
+        whenever(dirFinder.getCSVOutputDir()).thenReturn(outputDir.absolutePath)
         behavior.onExportCSV()
         verify(screen).showSendFileScreen(any())
         assertThat(FileUtils.listFiles(outputDir, null, false).size, equalTo(1))
@@ -104,7 +103,7 @@ class ListHabitsBehaviorTest : BaseUnitTest() {
     fun testOnExportCSV_fail() {
         val outputDir = Files.createTempDirectory("CSV").toFile()
         outputDir.setWritable(false)
-        whenever(dirFinder.getCSVOutputDir()).thenReturn(outputDir)
+        whenever(dirFinder.getCSVOutputDir()).thenReturn(outputDir.absolutePath)
         behavior.onExportCSV()
         verify(screen).showMessage(ListHabitsBehavior.Message.COULD_NOT_EXPORT)
         assertTrue(outputDir.delete())
@@ -132,13 +131,12 @@ class ListHabitsBehaviorTest : BaseUnitTest() {
     }
 
     @Test
-    @Throws(IOException::class)
     fun testOnSendBugReport() {
         whenever(bugReporter.getBugReport()).thenReturn("hello")
         behavior.onSendBugReport()
         verify(bugReporter).dumpBugReportToFile()
         verify(screen).showSendBugReportToDeveloperScreen("hello")
-        whenever(bugReporter.getBugReport()).thenThrow(IOException())
+        whenever(bugReporter.getBugReport()).thenThrow(RuntimeException())
         behavior.onSendBugReport()
         verify(screen).showMessage(ListHabitsBehavior.Message.COULD_NOT_GENERATE_BUG_REPORT)
     }

uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/ui/screens/habits/show/ShowHabitMenuPresenterTest.kt

@@ -61,7 +61,7 @@ class ShowHabitMenuPresenterTest : BaseUnitTest() {
     @Throws(Exception::class)
     fun testOnExport() {
         val outputDir = Files.createTempDirectory("CSV").toFile()
-        whenever(system.getCSVOutputDir()).thenReturn(outputDir)
+        whenever(system.getCSVOutputDir()).thenReturn(outputDir.absolutePath)
         menu.onExportCSV()
         assertThat(FileUtils.listFiles(outputDir, null, false).size, equalTo(1))
         FileUtils.deleteDirectory(outputDir)

uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/utils/FileExtensionsTest.kt

@@ -1,5 +1,7 @@
 package org.isoron.uhabits.core.utils
 
+import kotlinx.coroutines.runBlocking
+import org.isoron.platform.io.JavaUserFile
 import org.isoron.uhabits.core.BaseUnitTest
 import org.junit.Test
 import java.io.File
@@ -8,10 +10,11 @@ import kotlin.test.assertTrue
 class FileExtensionsTest : BaseUnitTest() {
 
     @Test
-    fun testIsSQLite3File() {
+    fun testIsSQLite3File() = runBlocking {
         val file = File.createTempFile("asset", "")
         copyAssetToFile("loop.db", file)
-        val isSqlite3File = file.isSQLite3File()
+        val userFile = JavaUserFile(file.toPath())
+        val isSqlite3File = isSQLite3File(userFile)
         assertTrue(isSqlite3File)
     }
 }