add getBelow() in Matchfield - DefaultCase

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

@@ -44,7 +44,12 @@ public class Matchfield {
 		if (x == 0) {
 			return null;
 		}
-		return matchfield[x][y];
+		return this.matchfield[x][y];
+	}
+
+	public Coordinate getBelow(Coordinate center) {
+		// TODO Auto-generated method stub
+		return this.matchfield[center.getX() - 1][center.getY()];
 	}
 
 }

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

@@ -79,4 +79,18 @@ class MatchfieldCreationTest {
 						matchfield.getField(6, 5)),
 				Arguments.of("above from (0/5) - should be null", matchfield, new Coordinate(0, 5), null));
 	}
+
+	@ParameterizedTest(name = "Get the Coordinate below")
+	@MethodSource("getCoordinateBelow")
+	void testGetBelow(String testName, Matchfield matchfield, Coordinate center, Coordinate expectedResult) {
+
+		Coordinate result = matchfield.getBelow(center);
+		assertThat(result).describedAs(testName).isEqualTo(expectedResult);
+	}
+
+	static Stream<Arguments> getCoordinateBelow() {
+		Matchfield matchfield = new Matchfield(10);
+		return Stream.of(Arguments.of("bewlow from (5/5) - should be (4,5)", matchfield, new Coordinate(5, 5),
+				matchfield.getField(4, 5)));
+	}
 }