add DeafaultState(EMPTY) to Coordinate

src/main/java/de/tims/fleetstorm/matchfield/Coordinate.java

@@ -3,10 +3,17 @@ package de.tims.fleetstorm.matchfield;
 public class Coordinate {
 	private int x;
 	private int y;
+	private int state;
+
+	public static final int EMPTY = 0;
+	public static final int SHIP = 1;
+	public static final int SHOT = 2;
+	public static final int HIT = 3;
 
 	public Coordinate(int x, int y) {
 		this.x = x;
 		this.y = y;
+		this.state = 0;
 	}
 
 	public Integer getX() {
@@ -17,4 +24,7 @@ public class Coordinate {
 		return y;
 	}
 
+	public int getState() {
+		return this.state;
+	}
 }

src/test/java/de/tims/fleetstorm/matchfield/CoordinateTest.java

@@ -17,4 +17,9 @@ class CoordinateTest {
 		assertEquals(coordinate.getY(), y);
 	}
 
+	@Test
+	void testCoordinatehasDefaultStates() {
+		assertEquals(coordinate.getState(), Coordinate.EMPTY);
+		assertEquals(coordinate.getState(), 0);
+	}
 }