Improve unit testing

src/main/java/com/goxr3plus/streamplayer/stream/StreamPlayer.java

@@ -1067,12 +1067,18 @@ public float getMinimumGain() {
 
 	/**
 	 * Returns Pan precision.
+	 * <p>
+	 * Obtains the resolution or granularity of the control, in the units that the control measures.
+	 * The precision is the size of the increment between discrete valid values for this control,
+	 * over the set of supported floating-point values.
 	 *
-	 * @return The Precision Value
+	 * @return The Precision Value for the pan control, if it exists, otherwise 0.0.
 	 */
 	@Override
 	public float getPrecision() {
-		return !outlet.hasControl(FloatControl.Type.PAN, outlet.getPanControl()) ? 0.0F : outlet.getPanControl().getPrecision();
+		return !outlet.hasControl(FloatControl.Type.PAN, outlet.getPanControl())
+				? 0
+				: outlet.getPanControl().getPrecision();
 
 	}
 

src/test/java/com/goxr3plus/streamplayer/stream/StreamPlayerFutureImprovementTest.java

@@ -0,0 +1,73 @@
+package com.goxr3plus.streamplayer.stream;
+
+import com.goxr3plus.streamplayer.enums.Status;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import javax.sound.sampled.AudioFileFormat;
+import javax.sound.sampled.AudioSystem;
+import javax.sound.sampled.SourceDataLine;
+import javax.sound.sampled.UnsupportedAudioFileException;
+import java.io.File;
+import java.io.IOException;
+import java.util.List;
+import java.util.logging.Logger;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests of all or most of the public methods of StreamPlayer.
+ * These unit tests are written primarily as documentation of the behavior and as example use case,
+ * not as a part of test driven development.
+ */
+public class StreamPlayerFutureImprovementTest {
+    StreamPlayer player;
+    private File audioFile;
+
+    @BeforeEach
+    void setup() {
+        final Logger logger = mock(Logger.class);
+        player = new StreamPlayer(logger);
+        audioFile = new File("Logic - Ballin [Bass Boosted].mp3");
+    }
+
+    /**
+     * This test fails if it's permitted to add a null to the StreamPlayer listener list.
+     */
+    @Test
+    void addStreamPlayerListener_dontAcceptNull() {
+        // Currently, we can add a null to the list of stream player listeners.
+        // Should that really be allowed?
+        assertThrows(Exception.class, () -> player.addStreamPlayerListener(null));
+
+        fail("Test not done");
+    }
+
+
+    @Test
+    @DisplayName("When play() is called without first calling open(), an exception is thrown")
+    void playingUnopenedSourceThrowsException() {
+
+        assertThrows(Exception.class, () -> player.play());
+    }
+
+    @Test
+    void seekBytes() throws StreamPlayerException {
+        player.open(audioFile);
+        player.play();
+        int positionByte1 = player.getPositionByte();
+
+        player.seekBytes(100);
+        int positionByte2 = player.getPositionByte();
+
+        assertTrue( positionByte2 > positionByte1);
+
+        // TODO: It seems that getPositionByte doesn't work.
+        //  It isn't called from within this project, except for in this test.
+        //  It is however called by XR3Player. If XR3Player needs this method, it must be tested
+        //  within this project. The method relies on a map, which doesn't seem to be updated by play()
+    }
+
+}