Update Unit Test Snake

src/test/java/SnakeTest.java

@@ -27,7 +27,9 @@ class SnakeTest {
 
     @Test
     public void testIsSelfColliding() {
+        int gridSize = 20;
+        Snake snake = new Snake(gridSize);
 
-
+        assertFalse(snake.isSelfColliding());
     }
 }