Added partial test suite for GStreamerPlayer.

src/main/java/musicplayer/model/Song.java

@@ -40,6 +40,27 @@ public class Song implements Comparable<Song>, IDBType {
     protected Song() {
     }
 
+    /**
+     * Create a song from ExtractedMetadata.
+     * This will always create new model objects (Album, Artist, etc). Use the verbose constructor if you need
+     * proper relationship behaviour between Songs and other model classes.
+     * @param metadata Song metadata.
+     */
+    public Song(ExtractedMetadata metadata){
+        this(metadata.getTrackNumber(), metadata.getDiscNumber(), metadata.getTitle(), new Artist(metadata.getArtist()),
+                new Album(metadata.getAlbum()), metadata.getGenre(), metadata.getSongFile());
+    }
+
+    /**
+     * Representation of a music file.
+     * @param trackNumber Track number.
+     * @param discNumber Disc number.
+     * @param title Song title.
+     * @param artist Song artist.
+     * @param album Song album.
+     * @param genre Song genre.
+     * @param songFile String representation of file path.
+     */
     public Song(String trackNumber, String discNumber, String title, Artist artist, Album album, String genre, String songFile) {
         updateData(trackNumber, discNumber, title, artist, album, genre, songFile);
     }

src/main/java/musicplayer/player/GStreamerPlayer.java

@@ -28,15 +28,21 @@ public class GStreamerPlayer implements IPlayer{
     /**
      * Manages GStreamer based playback operations.
      * @param callbackInterface Interface on which UI updates can be called.
+     * @param playlist Playlist containing music to play.
      */
     @Inject
     public GStreamerPlayer(PlayerCallbackInterface callbackInterface, IPlaylist playlist){
+        this(callbackInterface, playlist, false);
+    }
+
+    public GStreamerPlayer(PlayerCallbackInterface callbackInterface, IPlaylist playlist, boolean testMode) {
         this.callbackInterface = callbackInterface;
         this.playlist = playlist;
         Gst.init();
         playBin = new PlayBin2("BusMessages");
         playBin.setVideoSink(ElementFactory.make("fakesink", "videosink"));
-
+        if(testMode) // Null output for testing
+            playBin.setAudioSink(ElementFactory.make("fakesink", "audiosink"));
         playBin.connect((PlayBin2.ABOUT_TO_FINISH) playBin2 -> {
             Thread callbackThing = new Thread(() -> {
                 try {

src/test/java/musicplayer/player/GStreamerPlayerTest.java

@@ -0,0 +1,83 @@
+package musicplayer.player;
+
+import musicplayer.model.Song;
+import musicplayer.playlist.IPlaylist;
+import musicplayer.playlist.JTablePlaylist;
+import musicplayer.util.LibraryUtils;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.File;
+import java.util.Optional;
+
+import static org.junit.Assert.*;
+
+public class GStreamerPlayerTest {
+
+    GStreamerPlayer player;
+    IPlaylist playlist;
+    Song sampleSong = new Song(LibraryUtils.autoParse(
+            new File(GStreamerPlayerTest.class.getResource("/sample.mp3").getFile()).toPath()).get());
+
+    @Before
+    public void setUp() throws Exception {
+        playlist = new JTablePlaylist();
+        player = new GStreamerPlayer(null, playlist, true);
+    }
+
+    @Test
+    public void testPlayEmptyPlaylist() throws Exception {
+        player.play();
+        assertFalse(player.isPlaying());
+    }
+
+    @Test
+    public void testPlay() throws Exception {
+        playlist.addSong(sampleSong);
+        player.play();
+        assertTrue(player.isPlaying());
+    }
+
+    @Test
+    public void testPlaySong() throws Exception {
+        player.playSong(Optional.of(sampleSong));
+        assertTrue(player.isPlaying());
+        assertEquals(sampleSong, player.getCurrentSong());
+    }
+
+    @Test
+    public void testStop() throws Exception {
+        player.playSong(Optional.of(sampleSong));
+        assertTrue(player.isPlaying());
+        player.stop();
+        assertFalse(player.isPlaying());
+    }
+
+    @Test
+    public void testResume() throws Exception {
+    }
+
+    @Test
+    public void testPause() throws Exception {
+        player.playSong(Optional.of(sampleSong));
+        assertTrue(player.isPlaying());
+        player.pause();
+        assertFalse(player.isPlaying());
+    }
+
+    @Test
+    public void testSetVolume() throws Exception {
+        assertEquals(100, player.getVolume());
+        int newVolume = 25;
+        player.setVolume(25);
+        assertEquals(newVolume, player.getVolume());
+    }
+
+    @Test
+    public void testSeek() throws Exception {
+        player.playSong(Optional.of(sampleSong));
+        assertTrue(player.isPlaying());
+        player.seek(100);
+        assertTrue(player.currentSongPosition() >= 100);
+    }
+}