Consistency checks for dynamic strings, before adding "Frère Jacques" song.

app/src/main/java/com/nicobrailo/pianoli/Theme.java

@@ -6,6 +6,7 @@
 import androidx.core.graphics.ColorUtils;
 
 public class Theme {
+    public static final String PREFIX = "theme_";
 
     private final KeyColor[] colors;
 

app/src/main/java/com/nicobrailo/pianoli/melodies/Melody.java

@@ -1,10 +1,8 @@
 package com.nicobrailo.pianoli.melodies;
 
 import android.util.Log;
-import com.nicobrailo.pianoli.song.ImALittleTeapot;
-import com.nicobrailo.pianoli.song.InsyWinsySpider;
-import com.nicobrailo.pianoli.song.TwinkleTwinkleLittleStar;
-import com.nicobrailo.pianoli.song.WaltzingMatilda;
+import com.nicobrailo.pianoli.song.*;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Parsed representation of a children's song.
@@ -15,6 +13,8 @@ public class Melody {
     /** Log tag */
     public static final String TAG = "MELODY";
 
+    public static final String PREFIX = "melody_";
+
     /**
      * All songs known to PianOli.
      *
@@ -28,7 +28,8 @@ public class Melody {
             TwinkleTwinkleLittleStar.melody,
             InsyWinsySpider.melody,
             ImALittleTeapot.melody,
-            WaltzingMatilda.melody
+            WaltzingMatilda.melody,
+            BrotherJohn.melody,
     };
 
     /**
@@ -76,4 +77,12 @@ public String getId() {
     public int[] getNotes() {
         return notes;
     }
+
+    @NotNull
+    @Override
+    public String toString() {
+        return "Melody{" +
+                '\'' + id + '\'' +
+                ", " + notes.length + " notes}";
+    }
 }

app/src/main/java/com/nicobrailo/pianoli/song/BrotherJohn.java

@@ -0,0 +1,44 @@
+package com.nicobrailo.pianoli.song;
+
+import com.nicobrailo.pianoli.melodies.Melody;
+
+/**
+ * The massively translated Frère Jacques ("Are you sleeping, Brother John?")
+ *
+ * <p>
+ * This nursery rhyme has been translated to dozens of languages, so it should reach a very wide audience.
+ * </p>
+ *
+ * <p>
+ * Compared to the classic C-D-E-C arrangement, this version is up-shifted by three full notes,
+ * to account for the bass-note the final chord. Without this shift, it would fall below where we have sound samples.
+ * </p>
+ *
+ *
+ * <p>
+ * Further reading:<ul>
+ * <li><a href="https://en.wikipedia.org/wiki/Fr%C3%A8re_Jacques">English Wikipedia: Frère Jacques</a></li>
+ * <li><a href="https://de.wikipedia.org/wiki/Fr%C3%A8re_Jacques">German Wikipedia: Frère Jacques</a>  (listing some 50 translations)</li>
+ * </ul></p>
+ */
+public class BrotherJohn {
+    public static final Melody melody = Melody.fromString(
+            "brother_john",
+            " " + // 'useless' string so that code formatting indentation nicely lines up
+                    // Are you sleeping, 2x
+                    "F G A F " +
+                    "F G A F " +
+
+                    // Brother John? 2x
+                    "A A# C2 " +
+                    "A A# C2 " +
+
+                    // Morning bells are ringing! 2x
+                    "C2 D2 C2 A# A F " +
+                    "C2 D2 C2 A# A F " +
+
+                    // Please come on! 2x
+                    "F C F " +
+                    "F C F "
+    );
+}

app/src/main/res/values-de-rDE/strings.xml

@@ -24,4 +24,6 @@
     <string name="theme_black_and_white">schwarz-weiß</string>
     <string name="melody_twinkle_twinkle_little_star">Morgen kommt der Weihnachtsmann</string>
     <string name="melody_waltzing_matilda">Waltzing Matilda</string>
-</resources>
+    <string name="soundset_piano2">Piano 2</string>
+    <string name="melody_brother_john">Bruder Jakob</string>
+</resources>

app/src/main/res/values-nl/strings.xml

@@ -30,4 +30,6 @@
     <string name="melody_im_a_little_teapot">Ik ben een Kleine Theepot</string>
     <string name="preferences">Voorkeuren</string>
     <string name="melody_waltzing_matilda">Waltzing Matilda</string>
-</resources>
+    <string name="soundset_piano2">Piano 2</string>
+    <string name="melody_brother_john">Vader Jacob</string>
+</resources>

app/src/main/res/values/strings.xml

@@ -17,9 +17,11 @@
     <string name="soundset_guitar">Guitar</string>
     <string name="soundset_musicbox">Music Box</string>
     <string name="soundset_piano">Piano</string>
+    <string name="soundset_piano2">Piano 2</string>
     <string name="soundset_sine">Sine Wave</string>
     <string name="soundset_vibraphone">Vibraphone</string>
 
+
     <!-- Song player settings -->
     <string name="pref_enable_melodies">Auto play melodies</string>
     <string name="pref_enable_melodies_summary">Touching a key plays the next note in a melody, rather than the key\'s
@@ -34,6 +36,7 @@
     <string name="melody_im_a_little_teapot">I\'m a Little Teapot</string>
     <string name="melody_insy_winsy_spider">Incy Winsy Spider</string>
     <string name="melody_waltzing_matilda">Waltzing Matilda</string>
+    <string name="melody_brother_john">Brother John</string>
 
     <!-- keyboard colour themes -->
     <string name="theme">Key Colours</string>

app/src/test/java/com/nicobrailo/pianoli/AssertionsExt.java

@@ -0,0 +1,16 @@
+package com.nicobrailo.pianoli;
+
+import org.junit.jupiter.api.Assertions;
+
+import java.util.Collection;
+
+public class AssertionsExt {
+    /**
+     * Fails (with <code>message</code>) if collection <code>haystack</code> does not contain <code>needle</code>.
+     */
+    public static <T> void assertContains(Collection<T> haystack, T needle, String message) {
+        if (!haystack.contains(needle)) {
+            Assertions.fail(message);
+        }
+    }
+}

app/src/test/java/com/nicobrailo/pianoli/DynamicTranslationIdentifierTest.java

@@ -0,0 +1,237 @@
+package com.nicobrailo.pianoli;
+
+import android.content.Context;
+import android.content.res.AssetManager;
+import com.nicobrailo.pianoli.melodies.Melody;
+import com.nicobrailo.pianoli.sound.SoundSet;
+import org.jetbrains.annotations.NotNull;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.io.IOException;
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static com.nicobrailo.pianoli.AssertionsExt.*;
+
+/**
+ * Consistency checks for dynamically-accessed entities: do they have translation-strings?
+ *
+ * <p>There are a few entities in PianOli that are derived dynamically at runtime.
+ * The IDE/Compiler cannot us in ensuring these have internationalisation strings, or that a particular string
+ * is never used.
+ * These unit tests cover those holes for the following entities:
+ * <ul>
+ *     <li>SoundSets</li>
+ *     <li>Themes</li>
+ *     <li>Melodies</li>
+ * </ul>
+ * </p>
+ */
+public class DynamicTranslationIdentifierTest {
+    /**
+     * Ensures that all available {@link com.nicobrailo.pianoli.sound.SampledSoundSet}s are translatable.
+     *
+     * <p>
+     * It does so by checking if each "soundset_FOO" folder under <code>src/main/assets/</code> has
+     * a matching entry in <code>src/main/res/values/strings.xml</code>.
+     * </p>
+     * <p>
+     * We do <em>not</em> test if the translation exists in all languages; test-failures due to (lack of) translation
+     * progress is a distraction, and not something the developer can control.
+     * Instead, we ensure that
+     * </p>
+     *
+     * @see com.nicobrailo.pianoli.sound.SampledSoundSet
+     * @see SoundSet#PREFIX
+     * @see SoundSet#getAvailableSoundsets(AssetManager)
+     * @see SettingsFragment#loadSounds()
+     */
+    @ParameterizedTest
+    @MethodSource("getSoundSets")
+    public void testSoundsetsHaveTranslationEntities(Path soundsetAssetFolder) {
+        List<String> translatables = getSoundSetTranslations();
+
+        String folderName = soundsetAssetFolder.getFileName().toString();
+
+        assertContains(translatables, folderName,
+                "Asset folder '" + soundsetAssetFolder + "' has no translation string in app/src/main/res/values/strings.xml");
+    }
+
+    /**
+     * Ensures our translations actually have a soundset backing them.
+     *
+     * <p>
+     * Inverse of {@link #testSoundsetsHaveTranslationEntities(Path)}, useful if we rename or delete asset folders.
+     * </p>
+     */
+    @ParameterizedTest
+    @MethodSource("getSoundSetTranslations")
+    public void testNoLeftoverSoundSetTranslations(String translationIdentifier) throws IOException {
+        List<String> soundSetAssets = getSoundSets().stream()
+                .map(Path::getFileName)
+                .map(Path::toString)
+                .collect(Collectors.toList());
+
+        assertContains(soundSetAssets, translationIdentifier,
+                "Translation id '" + translationIdentifier + "' translates a soundset that doesn't exist in src/main/assets/");
+    }
+
+
+    /**
+     * Ensures that all specific {@link Theme}s are translatable.
+     *
+     * @see Theme
+     * @see Theme#PREFIX
+     * @see Theme#fromPreferences(Context)
+     * @see Preferences#selectedTheme(Context)
+     * @see R.xml#root_preferences
+     */
+    @ParameterizedTest
+    @MethodSource("getThemes")
+    public void testThemesHaveTranslationEntities(String themeName) {
+        List<String> translatables = getThemeTranslations();
+
+        String matchingForm = Theme.PREFIX + themeName.toLowerCase(Locale.ROOT);
+        assertContains(translatables, matchingForm,
+                "Theme '" + themeName + "' has no translation string ('" + matchingForm + "') in app/src/main/res/values/strings.xml");
+    }
+
+    /**
+     * Ensures our translations actually have a Theme backing them.
+     *
+     * <p>
+     * Inverse of {@link #testThemesHaveTranslationEntities(String)}, useful if we rename or delete themes.
+     * </p>
+     */
+    @ParameterizedTest
+    @MethodSource("getThemeTranslations")
+    public void testNoLeftoverThemeTranslations(String translationIdentifier) {
+        List<String> themes = getThemes();
+
+        String matchingForm = translationIdentifier
+                .replaceFirst("^" + Theme.PREFIX, "")
+                .toUpperCase(Locale.ROOT);
+        assertContains(themes, matchingForm,
+                "Translation id '" + translationIdentifier + "' translates a theme that doesn't exist in Theme.java " +
+                        "(" + themes + ")");
+    }
+
+
+    /**
+     * Ensures that all specific {@link Melody Melodies} are translatable.
+     *
+     * @see Melody
+     * @see Melody#PREFIX
+     * @see Melody#all
+     * @see SettingsFragment#loadMelodies()
+     */
+    @ParameterizedTest
+    @MethodSource("getMelodies")
+    public void testMelodiesHaveTranslationEntities(String melodyId) {
+        List<String> translatables = getMelodyTranslations();
+
+        String matchingForm = Melody.PREFIX + melodyId.toLowerCase(Locale.ROOT);
+        assertContains(translatables, matchingForm,
+                "Melody '" + melodyId + "' has no translation string ('" + matchingForm + "') in app/src/main/res/values/strings.xml");
+    }
+
+
+    /**
+     * Ensures our translations actually have a melody backing them.
+     *
+     * <p>
+     * Inverse of {@link #testMelodiesHaveTranslationEntities(String)}, useful if we rename or delete melodies.
+     * </p>
+     */
+    @ParameterizedTest
+    @MethodSource("getMelodyTranslations")
+    public void testNoLeftoverMelodyTranslations(String translationIdentifier) {
+        List<String> melodies = getMelodies();
+
+        String matchingForm = translationIdentifier
+                .replaceFirst("^" + Melody.PREFIX, "");
+
+        assertContains(melodies, matchingForm,
+                "Translation id '" + translationIdentifier + "' translates a melody that doesn't exist in Melody.java " +
+                        "(" + melodies + ")");
+    }
+
+    /**
+     * Scans the primary translation string source for identifiers starting with <code>prefix</code>
+     */
+    private static List<String> getTranslationsByPrefix(String prefix) {
+        // All String-resource identifiers
+        Field[] allStrings = R.string.class.getFields();
+
+        return Arrays.stream(allStrings)
+                .map(Field::getName)
+                .filter(name -> name.startsWith(prefix))
+                .collect(Collectors.toList());
+    }
+
+    /**
+     * {@link MethodSource} for all soundset translation identifiers
+     */
+    public static List<String> getSoundSetTranslations() {
+        return getTranslationsByPrefix(SoundSet.PREFIX);
+    }
+
+    /**
+     * {@link MethodSource} for all soundset asset folders
+     */
+    @NotNull
+    public static List<Path> getSoundSets() throws IOException {
+        Path soundAssets = Paths.get("src/main/assets/sounds"); // app-tests run in app-folder (at least on my IDE)
+
+        try (Stream<Path> pathStream = Files.list(soundAssets)) {
+            return pathStream
+                    .filter(Files::isDirectory) // skip top-level files (specifically: "source" attribution file)
+                    .filter(path -> path.getFileName().toString().startsWith(SoundSet.PREFIX))
+                    .collect(Collectors.toList());
+        }
+    }
+
+    /**
+     * {@link MethodSource} for all theme translation identifiers
+     */
+    public static List<String> getThemeTranslations() {
+        return getTranslationsByPrefix(Theme.PREFIX);
+    }
+
+    /**
+     * {@link MethodSource} for all themes known to PianOli
+     *
+     * @see Theme
+     */
+    public static List<String> getThemes() {
+        Field[] fields = Theme.class.getDeclaredFields();
+        return Arrays.stream(fields)
+                .filter(field -> Theme.class.equals(field.getType()))
+                .filter(field -> Modifier.isStatic(field.getModifiers()))
+                .map(Field::getName)
+                .collect(Collectors.toList());
+    }
+
+
+    /**
+     * {@link MethodSource} for all melody translation identifiers
+     */
+    public static List<String> getMelodyTranslations() {
+        return getTranslationsByPrefix(Melody.PREFIX);
+    }
+
+    public static List<String> getMelodies() {
+        return Arrays.stream(Melody.all)
+                .map(Melody::getId)
+                .collect(Collectors.toList());
+    }
+}