diff --git a/src/main/java/dotsandboxes/DotsAndBoxesGrid.java b/src/main/java/dotsandboxes/DotsAndBoxesGrid.java
index 32667af6c63a0287bd4f91c37682acb30c08e9a4..99babeb42962386d105fdbb7152c6cd10338bf30 100644
--- a/src/main/java/dotsandboxes/DotsAndBoxesGrid.java
+++ b/src/main/java/dotsandboxes/DotsAndBoxesGrid.java
@@ -112,8 +112,11 @@ public class DotsAndBoxesGrid {
         }
 
         // 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;
+        if (this.horizontals[x][y] == true && this.horizontals[x][y+1] == true &&  this.verticals[x][y] == true && this.verticals[x+1][y] == true) {
+            return true;
+        }
+
+        return false;
     }
 
     /** Tries to claim a box for a player. If the box is complete, sets the ownership and returns true. */
@@ -141,6 +144,10 @@ public class DotsAndBoxesGrid {
         }
 
         // FIXME: You need to throw an exception if the line was already drawn.
+        if (this.horizontals[x][y] == true) {
+            throw new IllegalStateException(String.format("IllegalStateException - This line has already been drawn"));
+            }
+
 
         this.horizontals[x][y] = true;
 
@@ -172,6 +179,9 @@ public class DotsAndBoxesGrid {
         }
 
         // You need to throw an exception if the line was already drawn.
+        if (this.verticals[x][y]) {
+                throw new IllegalStateException(String.format("This line has already been drawn"));
+        }
 
         this.verticals[x][y] = true;
         // Try to claim the north or south boxes
diff --git a/src/test/java/dotsandboxes/DotsAndBoxesGridTest.java b/src/test/java/dotsandboxes/DotsAndBoxesGridTest.java
index bca1591613cb005fb51cdb9ba11bab337c715b0e..64b3674dbfcf90e41fc489f885ba7fc215078c0d 100644
--- a/src/test/java/dotsandboxes/DotsAndBoxesGridTest.java
+++ b/src/test/java/dotsandboxes/DotsAndBoxesGridTest.java
@@ -32,13 +32,13 @@ public class DotsAndBoxesGridTest {
     @Test
     public void testTestingBoxComplete() {
         logger.info("Test of box completion test");
-        logger.info("Drawing complete box, then asserting incomplete state");
+        logger.info("Drawing complete box, then asserting complete state");
         DotsAndBoxesGrid g = new DotsAndBoxesGrid(4,4,1);
         g.drawHorizontal(1,1, 1);
         g.drawHorizontal(1,2,1);
         g.drawVertical(1,1,1);
         g.drawVertical(2,1,1);
-        assertEquals(false,g.boxComplete(1,1));
+        assertEquals(true,g.boxComplete(1,1));
     }
 
     @Test