🧪 Add tests for Theme appearance preferences

.jules/testing.md

@@ -0,0 +1,3 @@
+## 2023-11-20 - [Testing preferences that use EncryptedSharedPreferences]
+**Learning:** `EncryptedSharedPreferences` requires an Android Keystore which doesn't work correctly in basic Robolectric tests due to missing cryptographic algorithm implementations (java.security.KeyStoreException).
+**Action:** When testing classes like `AppearancePreferences` that rely on `EncryptedSharedPreferences`, create a `Fake` wrapper class that overrides the internal `SharedPreferences` object with a basic, in-memory implementation for testing, rather than trying to configure Robolectric to support the Android KeyStore correctly.

app/src/main/java/com/rockmusic/app/presentation/theme/AppearancePreferences.kt

@@ -36,18 +36,22 @@ val AppearanceSettingsSaver: Saver<AppearanceSettings, Any> = listSaver(
     },
 )
 
-class AppearancePreferences(context: Context) {
-    private val masterKey = MasterKey.Builder(context)
-        .setKeyScheme(MasterKey.KeyScheme.AES256_GCM)
-        .build()
+open class AppearancePreferences(context: Context) {
+    private val masterKey by lazy {
+        MasterKey.Builder(context)
+            .setKeyScheme(MasterKey.KeyScheme.AES256_GCM)
+            .build()
+    }
 
-    private val preferences = EncryptedSharedPreferences.create(
-        context,
-        PREFERENCES_NAME,
-        masterKey,
-        EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
-        EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM,
-    )
+    public open val preferences: android.content.SharedPreferences by lazy {
+        EncryptedSharedPreferences.create(
+            context,
+            PREFERENCES_NAME,
+            masterKey,
+            EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
+            EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM,
+        )
+    }
 
     fun load(): AppearanceSettings = AppearanceSettings(
         themeMode = runCatching {

app/src/test/java/com/rockmusic/app/presentation/theme/AppearancePreferencesTest.kt

@@ -0,0 +1,130 @@
+package com.rockmusic.app.presentation.theme
+
+import android.content.Context
+import android.content.SharedPreferences
+import androidx.test.core.app.ApplicationProvider
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+import androidx.compose.runtime.saveable.SaverScope
+
+class FakeAppearancePreferences(context: Context) : AppearancePreferences(context) {
+    private val store = mutableMapOf<String, Any>()
+
+    override val preferences: SharedPreferences = object : SharedPreferences {
+        override fun getAll(): MutableMap<String, *> = store.toMutableMap()
+        override fun getString(key: String, defValue: String?): String? = store[key] as? String ?: defValue
+        override fun getStringSet(key: String, defValues: MutableSet<String>?): MutableSet<String>? { @Suppress("UNCHECKED_CAST") return store[key] as? MutableSet<String> ?: defValues }
+        override fun getInt(key: String, defValue: Int): Int = store[key] as? Int ?: defValue
+        override fun getLong(key: String, defValue: Long): Long = store[key] as? Long ?: defValue
+        override fun getFloat(key: String, defValue: Float): Float = store[key] as? Float ?: defValue
+        override fun getBoolean(key: String, defValue: Boolean): Boolean = store[key] as? Boolean ?: defValue
+        override fun contains(key: String): Boolean = store.containsKey(key)
+
+        override fun edit(): SharedPreferences.Editor = object : SharedPreferences.Editor {
+            override fun putString(key: String, value: String?): SharedPreferences.Editor {
+                if (value == null) store.remove(key) else store[key] = value
+                return this
+            }
+            override fun putStringSet(key: String, values: MutableSet<String>?): SharedPreferences.Editor {
+                if (values == null) store.remove(key) else store[key] = values
+                return this
+            }
+            override fun putInt(key: String, value: Int): SharedPreferences.Editor { store[key] = value; return this }
+            override fun putLong(key: String, value: Long): SharedPreferences.Editor { store[key] = value; return this }
+            override fun putFloat(key: String, value: Float): SharedPreferences.Editor { store[key] = value; return this }
+            override fun putBoolean(key: String, value: Boolean): SharedPreferences.Editor { store[key] = value; return this }
+            override fun remove(key: String): SharedPreferences.Editor { store.remove(key); return this }
+            override fun clear(): SharedPreferences.Editor { store.clear(); return this }
+            override fun commit(): Boolean = true
+            override fun apply() {}
+        }
+
+        override fun registerOnSharedPreferenceChangeListener(listener: SharedPreferences.OnSharedPreferenceChangeListener) {}
+        override fun unregisterOnSharedPreferenceChangeListener(listener: SharedPreferences.OnSharedPreferenceChangeListener) {}
+    }
+}
+
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [34])
+class AppearancePreferencesTest {
+
+    private lateinit var preferences: FakeAppearancePreferences
+
+    @Before
+    fun setup() {
+        preferences = FakeAppearancePreferences(ApplicationProvider.getApplicationContext())
+    }
+
+    @Test
+    fun load_returnsDefaultSettings_whenNoPreferencesSaved() {
+        val settings = preferences.load()
+
+        assertEquals(RockThemeMode.SYSTEM, settings.themeMode)
+        assertTrue(settings.useSystemColor)
+        assertTrue(settings.useBlurFrames)
+    }
+
+    @Test
+    fun save_and_load_restoresSavedSettings() {
+        val customSettings = AppearanceSettings(
+            themeMode = RockThemeMode.DARK,
+            useSystemColor = false,
+            useBlurFrames = false,
+        )
+
+        preferences.save(customSettings)
+
+        val loadedSettings = preferences.load()
+
+        assertEquals(RockThemeMode.DARK, loadedSettings.themeMode)
+        assertFalse(loadedSettings.useSystemColor)
+        assertFalse(loadedSettings.useBlurFrames)
+    }
+
+    @Test
+    fun load_handlesInvalidEnumSafely() {
+        preferences.preferences.edit().putString("theme_mode", "INVALID_ENUM_VALUE").commit()
+        val loadedSettings = preferences.load()
+        assertEquals(RockThemeMode.SYSTEM, loadedSettings.themeMode)
+    }
+
+    @Test
+    fun saver_savesAndRestoresCorrectly() {
+        val customSettings = AppearanceSettings(
+            themeMode = RockThemeMode.LIGHT,
+            useSystemColor = false,
+            useBlurFrames = false,
+        )
+
+        val savedList = with(AppearanceSettingsSaver) {
+            SaverScope { true }.save(customSettings)
+        } as List<*>
+
+        assertEquals(RockThemeMode.LIGHT.name, savedList[0])
+        assertEquals(false, savedList[1])
+        assertEquals(false, savedList[2])
+
+        val restoredSettings = AppearanceSettingsSaver.restore(savedList as Any)
+
+        assertEquals(customSettings, restoredSettings)
+    }
+
+    @Test
+    fun saver_handlesInvalidEnumSafely() {
+        val invalidList = listOf(
+            "INVALID_ENUM_VALUE",
+            true,
+            true,
+        )
+
+        val restoredSettings = AppearanceSettingsSaver.restore(invalidList)
+
+        assertEquals(RockThemeMode.SYSTEM, restoredSettings?.themeMode)
+    }
+}