Kandinsky: Add a test for KDRect intersections

Change-Id: I98c8ec0d6ed4117e93ec96a05905f5e1eab14d25

kandinsky/Makefile

@@ -10,6 +10,7 @@ objs += $(addprefix kandinsky/src/,\
 )
 tests += $(addprefix kandinsky/test/,\
   color.c\
+  rect.c\
   set_pixel.c\
 )
 

kandinsky/test/rect.c

@@ -0,0 +1,26 @@
+#include <quiz.h>
+#include <kandinsky.h>
+#include <assert.h>
+
+QUIZ_CASE(kandinsky_rect_intersect) {
+  KDRect a = {
+    .x = -5, .y = -5,
+    .width = 10, .height = 10
+  };
+  KDRect b = {
+    .x = 0, .y = 0,
+    .width = 10, .height = 10
+  };
+  assert(KDRectIntersect(a,b));
+  assert(KDRectIntersect(b,a));
+  KDRect c = KDRectIntersection(a,b);
+  assert(c.x == 0);
+  assert(c.y == 0);
+  assert(c.width == 5);
+  assert(c.height == 5);
+  c = KDRectIntersection(b,a);
+  assert(c.x == 0);
+  assert(c.y == 0);
+  assert(c.width == 5);
+  assert(c.height == 5);
+}