Game end: Draw, with Test

src/main/java/TicTacToe/TicTacToeGame.java

@@ -18,6 +18,7 @@ public class TicTacToeGame extends JPanel {
 	
 	public cell[] field;
 	public int playerID = 1;
+	public int turns = 0;
 	
 	public TicTacToeGame() {
 		this.setSize(width, height);
@@ -76,6 +77,12 @@ public class TicTacToeGame extends JPanel {
 			System.exit(0);
 		}
 		
+		turns++;
+		if(turns >= playFieldSize) {
+			JOptionPane.showMessageDialog(getParent(),"Draw!");	
+			System.exit(0);
+		}
+		
 		playerID++;
 		if(playerID >= maxPlayers) {
 			playerID = 1;

src/test/java/TicTacToe/TicTacToeGameTest.java

@@ -24,6 +24,21 @@ class TicTacToeGameTest {
 		assertEquals(_winner, realWinner);
 	}
 	
+	@ParameterizedTest
+	@MethodSource("testFieldsDraw")
+	void testGameEndDraw(int[] _field) {
+		TicTacToeGame ttt = new TicTacToeGame();
+		
+		for(int i = 0; i < ttt.field.length; i++) {
+			ttt.field[i].playerID = _field[i];
+		}
+		
+		int noWinner = ttt.checkPlayfield();
+		
+		assertEquals(0, noWinner);
+	}
+	
+	
 	private static Stream<Arguments> testFieldsWinning(){
 		return Stream.of(
 				Arguments.of(new int[]{	1,2,1,
@@ -39,6 +54,23 @@ class TicTacToeGameTest {
 										1,2,1,
 										1,1,2}, 2)
 				);
+	}
+		
+	private static Stream<Arguments> testFieldsDraw(){
+		return Stream.of(
+				Arguments.of(new int[]{	2,1,1,
+										2,2,2,
+										1,2,1}),
+				Arguments.of(new int[]{	2,1,2,
+										2,2,1,
+										1,2,1}),
+				Arguments.of(new int[]{	2,1,2,
+										1,2,2,
+										1,2,1}),
+				Arguments.of(new int[]{	2,1,1,
+										1,2,2,
+										2,1,1})
+				);
 				
 		
 	}