Fixed assignment errors: boxComplete correctly checks if a box is complete,...

Fixed assignment errors: boxComplete correctly checks if a box is complete, drawHorizontal correctly throws an exception if the line was already drawn and drawVertical correctly throws an exception if the line was already drawn

src/main/java/dotsandboxes/DotsAndBoxesGrid.java

@@ -5,6 +5,8 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.function.Consumer;
 
+import javax.management.RuntimeErrorException;
+
 /**
  * The state of a dots and boxes grid.
  *
@@ -111,7 +113,10 @@ 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).
+        if (!getHorizontal(x,y) || !getVertical(x, y) ||
+            !getHorizontal(x, y + 1) || !getVertical(x + 1, y)) {
+                return false;
+             }
         return true;
     }
 
@@ -139,7 +144,9 @@ 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.
+        if (getHorizontal(x, y)) {
+            throw new RuntimeException(String.format("This horizontal line has already been drawn"));
+        }
 
         this.horizontals[x][y] = true;
 
@@ -170,7 +177,9 @@ 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.
+        if (getVertical(x, y)) {
+            throw new RuntimeException(String.format("This vertical line has already been drawn"));
+        }
 
         this.verticals[x][y] = true;
         // Try to claim the north or south boxes