assignment errors has been fixed

src/main/java/dotsandboxes/DotsAndBoxesGrid.java

 package dotsandboxes;
 
-
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.function.Consumer;
@@ -50,6 +49,7 @@ public class DotsAndBoxesGrid {
 
     final int players;
     private int player = 1;
+
     public int getPlayer() {
         return player;
     }
@@ -98,7 +98,6 @@ public class DotsAndBoxesGrid {
         return boxOwners[x][y];
     }
 
-
     /**
      * Checks whether a box has been fully drawn (all four sides)
      * @param x coordinate of the left side of the box
@@ -110,9 +109,13 @@ public class DotsAndBoxesGrid {
             return false;
         }
 
-        // A box is complete if the north and south horizontals and the east and west verticals have all been drawn.
-        // FIXME: You'll need to fix this code (after writing a test first).
-        return true;
+        // Check if all sides of the box are drawn
+        boolean top = horizontals[x][y];
+        boolean bottom = horizontals[x][y + 1];
+        boolean left = verticals[x][y];
+        boolean right = verticals[x + 1][y];
+
+        return top && bottom && left && right;
     }
 
     /** Tries to claim a box for a player. If the box is complete, sets the ownership and returns true. */
@@ -139,7 +142,10 @@ public class DotsAndBoxesGrid {
             throw new IndexOutOfBoundsException(String.format("y was %d, which is out of range. Range is 0 to %d", y, height));
         }
 
-        // FIXME: You need to throw an exception if the line was already drawn.
+        // Throw an exception if the line was already drawn
+        if (horizontals[x][y]) {
+            throw new IllegalStateException("This horizontal line is already drawn.");
+        }
 
         this.horizontals[x][y] = true;
 
@@ -170,10 +176,14 @@ public class DotsAndBoxesGrid {
             throw new IndexOutOfBoundsException(String.format("y was %d, which is out of range. Range is 0 to %d", y, height - 1));
         }
 
-        // You need to throw an exception if the line was already drawn.
+        // Throw an exception if the line was already drawn
+        if (verticals[x][y]) {
+            throw new IllegalStateException("This vertical line is already drawn.");
+        }
 
         this.verticals[x][y] = true;
-        // Try to claim the north or south boxes
+
+        // Try to claim the east or west boxes
         boolean claimE = claimBox(x, y, player);
         boolean claimW = claimBox(x - 1, y, player);
         if (claimE || claimW) {
@@ -184,7 +194,6 @@ public class DotsAndBoxesGrid {
             notifyObservers();
             return false;
         }
-
     }
 
     public boolean gameComplete() {
@@ -192,6 +201,4 @@ public class DotsAndBoxesGrid {
         // The grid is complete if "for all rows, all the boxes in that row have a non-zero owner"
         return Arrays.stream(boxOwners).allMatch((row) -> Arrays.stream(row).allMatch((owner) -> owner > 0));
     }
-
-
 }

src/test/java/dotsandboxes/DotsAndBoxesGridTest.java

@@ -32,19 +32,19 @@ public class DotsAndBoxesGridTest {
         logger.info("Testing square completion logic");
 
         // Create a new game grid
-        DotsAndBoxesGrid grid = new DotsAndBoxesGrid();
+        DotsAndBoxesGrid grid = new DotsAndBoxesGrid(3, 3, 2);
 
         // Draw lines to form a square
-        grid.drawLine(0, 0, 0, 1); // Top horizontal line
-        grid.drawLine(0, 0, 1, 0); // Left vertical line
-        grid.drawLine(0, 1, 1, 1); // Bottom horizontal line
-        grid.drawLine(1, 0, 1, 1); // Right vertical line
+        grid.drawHorizontal(0, 0, 1); // Top horizontal line
+        grid.drawVertical(0, 0, 1);   // Left vertical line
+        grid.drawHorizontal(0, 1, 1); // Bottom horizontal line
+        grid.drawVertical(1, 0, 1);   // Right vertical line
 
         // Test if the square at (0, 0) is complete
-        boolean isComplete = grid.isSquareComplete(0, 0);
+        boolean isComplete = grid.boxComplete(0, 0);
         
-        // The bug is that isSquareComplete always returns true
-        assertFalse(isComplete, "The square completion check should fail because the method is broken.");
+        // The test should pass now that the logic is fixed
+        assertTrue(isComplete, "The square at (0, 0) should be complete.");
     }
 
     @Test
@@ -52,14 +52,22 @@ public class DotsAndBoxesGridTest {
         logger.info("Testing drawing the same line twice throws exception");
 
         // Create a new game grid
-        DotsAndBoxesGrid grid = new DotsAndBoxesGrid();
+        DotsAndBoxesGrid grid = new DotsAndBoxesGrid(3, 3, 2);
 
         // Draw a line once
-        grid.drawLine(0, 0, 0, 1);
+        grid.drawHorizontal(0, 0, 1);
         
         // Attempt to draw the same line again
         assertThrows(IllegalStateException.class, () -> {
-            grid.drawLine(0, 0, 0, 1);
-        }, "Drawing the same line twice should throw IllegalStateException.");
+            grid.drawHorizontal(0, 0, 1);
+        }, "Drawing the same horizontal line twice should throw IllegalStateException.");
+        
+        // Draw a vertical line once
+        grid.drawVertical(0, 0, 1);
+        
+        // Attempt to draw the same vertical line again
+        assertThrows(IllegalStateException.class, () -> {
+            grid.drawVertical(0, 0, 1);
+        }, "Drawing the same vertical line twice should throw IllegalStateException.");
     }
 }