Bug fixed

src/main/java/dotsandboxes/DotsAndBoxesGrid.java

@@ -111,8 +111,12 @@ public class DotsAndBoxesGrid {
         }
 
         // A box is complete if the north and south horizontals and the east and west verticals have all been drawn.
+        boolean north = horizontals[x][y];
+        boolean south = horizontals[x][y + 1];
+        boolean east = verticals[x + 1][y];
+        boolean west = verticals[x][y];
         // FIXME: You'll need to fix this code (after writing a test first).
-        return false;
+        return north && south && east && west;
     }
 
     /** Tries to claim a box for a player. If the box is complete, sets the ownership and returns true. */
@@ -140,7 +144,9 @@ public class DotsAndBoxesGrid {
         }
 
         // FIXME: You need to throw an exception if the line was already drawn.
-
+        if (horizontals[x][y]) {
+            throw new IllegalArgumentException("Already Drawn");
+        }
         this.horizontals[x][y] = true;
 
         // Try to claim the north or south boxes
@@ -171,6 +177,9 @@ public class DotsAndBoxesGrid {
         }
 
         // You need to throw an exception if the line was already drawn.
+        if (verticals[x][y]) {
+            throw new IllegalArgumentException("Already Drawn");
+        }
 
         this.verticals[x][y] = true;
         // Try to claim the north or south boxes

src/test/java/dotsandboxes/DotsAndBoxesGridTest.java

@@ -14,25 +14,29 @@ public class DotsAndBoxesGridTest {
     @BeforeEach
     public void setUp() {
         // Create a new DotsAndBoxesGrid instance before each test
-        grid = new DotsAndBoxesGrid(4, 3, 2);
+    	grid = new DotsAndBoxesGrid(15, 8, 2);
     }
 
     @Test
     public void testBoxComplete() {
         // Test if the boxComplete method works correctly
-
+        grid.drawHorizontal(3,3,1);
+        grid.drawHorizontal(3,4,1);
+        grid.drawVertical(3,3,1);
+        grid.drawVertical(4,3,1);
         assertTrue(grid.boxComplete(3,3));
     }
 
     @Test
    public void whenExceptionThrown_thenAssertionSucceeds() {
-        Exception exception = assertThrows(Exception.class, () -> {
+    	grid.drawHorizontal(3, 3, 1);
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> {
             grid.drawHorizontal(3,3,1);
         });
 
         String expectedMessage = "Already Drawn";
         String actualMessage = exception.getMessage();
-
+        System.out.println(actualMessage);
         assertTrue(actualMessage.contains(expectedMessage));
     }