Added tests for TackGybeCommand class.

#Story[1097]

racevisionGame/src/main/java/mock/model/commandFactory/TackGybeCommand.java

@@ -39,7 +39,7 @@ public class TackGybeCommand implements Command {
         }
     }
 
-    private double calcDistance(double degreeA, double degreeB){
+    public double calcDistance(double degreeA, double degreeB){
         double phi = Math.abs(degreeB - degreeA) % 360;
         double distance = phi > 180 ? 360 - phi : phi;
         return distance;

racevisionGame/src/test/java/mock/model/commandFactory/TackGybeCommandTest.java

@@ -0,0 +1,42 @@
+package mock.model.commandFactory;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Created by David on 7/08/2017.
+ */
+public class TackGybeCommandTest {
+
+    private double degreeA;
+    private double degreeB;
+    private double degreeC;
+    private double degreeD;
+    TackGybeCommand tgc;
+
+    //Run before tests
+    @Before
+    public void setUp(){
+        degreeA = 150.0;
+        degreeB = 300.0;
+        degreeC = 10.0;
+        degreeD = 350.0;
+        tgc = new TackGybeCommand(null, null);
+    }
+
+    //Test when degree difference is <180
+    @Test
+    public void angleDistanceCalculationLow(){
+        double result = tgc.calcDistance(degreeA, degreeB);
+        assertEquals(150.0, result, 0);
+    }
+
+    //Test when degree difference is >180
+    @Test
+    public void angleDistanceCalculationHigh(){
+        double result = tgc.calcDistance(degreeC, degreeD);
+        assertEquals(20.0, result, 0);
+    }
+}