Bug fixes (#319)

* Fix TTS speaker persistence

* optimized redundant WebView updates

* Bumped version to 1.0.48

app/src/test/java/com/aryan/reader/tts/TtsSpeakerPreferencesTest.kt

@@ -0,0 +1,41 @@
+package com.aryan.reader.tts
+
+import android.content.Context
+import org.junit.Assert.assertEquals
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.RuntimeEnvironment
+
+@RunWith(RobolectricTestRunner::class)
+class TtsSpeakerPreferencesTest {
+    private lateinit var context: Context
+
+    @Before
+    fun setUp() {
+        context = RuntimeEnvironment.getApplication()
+        context.getSharedPreferences(TTS_SETTINGS_PREFS_NAME, Context.MODE_PRIVATE)
+            .edit()
+            .clear()
+            .commit()
+    }
+
+    @Test
+    fun `tts speaker preference saves and loads selected ai voice`() {
+        saveTtsSpeaker(context, "Kore")
+
+        assertEquals("Kore", loadTtsSpeaker(context))
+    }
+
+    @Test
+    fun `tts speaker preference falls back to default for blank or unknown voices`() {
+        assertEquals(DEFAULT_SPEAKER_ID, loadTtsSpeaker(context))
+
+        saveTtsSpeaker(context, "")
+        assertEquals(DEFAULT_SPEAKER_ID, loadTtsSpeaker(context))
+
+        saveTtsSpeaker(context, "MissingVoice")
+        assertEquals(DEFAULT_SPEAKER_ID, loadTtsSpeaker(context))
+    }
+}