tictactoe: added restriction for board sizes below three

src/main/java/de/tims/tictactoe/GameLogic.java

@@ -5,6 +5,9 @@ public class GameLogic {
 	private int[][] board;
 
 	public GameLogic(int size) {
+		if (size < 3) {
+			size = 3;
+		}
 		this.board = new int[size][size];
 	}
 
@@ -13,7 +16,6 @@ public class GameLogic {
 	}
 
 	public int countFields() {
-		// TODO Auto-generated method stub
 		return this.board[0].length * this.board.length;
 	}
 

src/test/java/de/tims/tictactoe/GameLogicTest.java

@@ -52,6 +52,8 @@ class GameLogicTest {
 	 
 	 private static Stream<Arguments> testCasesForCountPlayfields() {
 		    return Stream.of(
+		    			Arguments.of("1x1 board with too few fields", 1, 9),
+		    			Arguments.of("2x2 board with too few fields", 2, 9),
 		    			Arguments.of("3x3 board with 9 playfields", 3, 9),
 		    			Arguments.of("4x4 board with 16 playfields", 4, 16),
 		    			Arguments.of("5x5 board with 25 playfields", 5,25)