[kandinsky] Add test cases for KDRect::differencedWith

Change-Id: I27371f94e590cb75712154b47efe4db27d0a082d

kandinsky/test/rect.cpp

@@ -58,3 +58,45 @@ QUIZ_CASE(kandinsky_rect_empty_union) {
   assert(t.width() == a.width());
   assert(t.height() == a.height());
 }
+
+QUIZ_CASE(kandinsky_rect_difference) {
+  KDRect a(-1, 0, 11, 2);
+  KDRect b(-4, -3, 4, 7);
+  KDRect c(3, -2, 1, 5);
+  KDRect d(7, -3, 5, 7);
+  KDRect e(-2, -1, 13, 5);
+  KDRect f(2, -4, 3, 3);
+
+  KDRect t = e.differencedWith(a);
+  assert(t == e);
+
+  t = a.differencedWith(e);
+  assert(t == KDRectZero);
+
+  t = f.differencedWith(d);
+  assert(t == f);
+
+  t = f.differencedWith(e);
+  assert(t == f);
+
+  t = b.differencedWith(e);
+  assert(t == b);
+
+  t = c.differencedWith(f);
+  assert(t == KDRect(3, -1, 1, 4));
+
+  t = c.differencedWith(a);
+  assert(t == c);
+
+  t = c.differencedWith(e);
+  assert(t == KDRect(3, -2, 1, 1));
+
+  t = a.differencedWith(b);
+  assert(t == KDRect(0, 0, 10, 2));
+
+  t = a.differencedWith(c);
+  assert(t == a);
+
+  t = a.differencedWith(d);
+  assert(t == KDRect(-1, 0, 8, 2));
+}