Index: uspace/lib/gfx/test/coord.c
===================================================================
--- uspace/lib/gfx/test/coord.c	(revision 7b882c1fb956e7997643c445ef2c7aed9e2891ff)
+++ uspace/lib/gfx/test/coord.c	(revision 87a7cdb3ff40f9795359f6da489d45a3fafee668)
@@ -95,3 +95,269 @@
 }
 
+/** Sorting span with lower start and higher end point results in the same span. */
+PCUT_TEST(span_points_sort_asc)
+{
+	gfx_coord_t a, b;
+
+	gfx_span_points_sort(1, 2, &a, &b);
+	PCUT_ASSERT_EQUALS(1, a);
+	PCUT_ASSERT_EQUALS(2, b);
+}
+
+/** Sorting span with same start and end point results in the same span. */
+PCUT_TEST(span_points_sort_equal)
+{
+	gfx_coord_t a, b;
+
+	gfx_span_points_sort(1, 1, &a, &b);
+	PCUT_ASSERT_EQUALS(1, a);
+	PCUT_ASSERT_EQUALS(1, b);
+}
+
+/** Sorting span with hight start and lower end point results in transposed span. */
+PCUT_TEST(span_points_sort_decs)
+{
+	gfx_coord_t a, b;
+
+	gfx_span_points_sort(1, 0, &a, &b);
+	PCUT_ASSERT_EQUALS(1, a);
+	PCUT_ASSERT_EQUALS(2, b);
+}
+
+/** Rectangle envelope with first rectangle empty should return the second rectangle. */
+PCUT_TEST(rect_envelope_a_empty)
+{
+	gfx_rect_t a;
+	gfx_rect_t b;
+	gfx_rect_t e;
+
+	a.p0.x = 0;
+	a.p0.y = 0;
+	a.p1.x = 0;
+	a.p1.y = 0;
+
+	b.p0.x = 1;
+	b.p0.y = 2;
+	b.p1.x = 3;
+	b.p1.y = 4;
+
+	gfx_rect_envelope(&a, &b, &e);
+	PCUT_ASSERT_EQUALS(1, e.p0.x);
+	PCUT_ASSERT_EQUALS(2, e.p0.y);
+	PCUT_ASSERT_EQUALS(3, e.p1.x);
+	PCUT_ASSERT_EQUALS(4, e.p1.y);
+}
+
+/** Rectangle envelope with second rectangle empty should return the first rectangle. */
+PCUT_TEST(rect_envelope_b_empty)
+{
+	gfx_rect_t a;
+	gfx_rect_t b;
+	gfx_rect_t e;
+
+	a.p0.x = 1;
+	a.p0.y = 2;
+	a.p1.x = 3;
+	a.p1.y = 4;
+
+	b.p0.x = 0;
+	b.p0.y = 0;
+	b.p1.x = 0;
+	b.p1.y = 0;
+
+	gfx_rect_envelope(&a, &b, &e);
+	PCUT_ASSERT_EQUALS(1, e.p0.x);
+	PCUT_ASSERT_EQUALS(2, e.p0.y);
+	PCUT_ASSERT_EQUALS(3, e.p1.x);
+	PCUT_ASSERT_EQUALS(4, e.p1.y);
+}
+
+/** Rectangle envelope, a has both coordinates lower than b */
+PCUT_TEST(rect_envelope_nonempty_a_lt_b)
+{
+	gfx_rect_t a;
+	gfx_rect_t b;
+	gfx_rect_t e;
+
+	a.p0.x = 1;
+	a.p0.y = 2;
+	a.p1.x = 3;
+	a.p1.y = 4;
+
+	b.p0.x = 5;
+	b.p0.y = 6;
+	b.p1.x = 7;
+	b.p1.y = 8;
+
+	gfx_rect_envelope(&a, &b, &e);
+	PCUT_ASSERT_EQUALS(1, e.p0.x);
+	PCUT_ASSERT_EQUALS(2, e.p0.y);
+	PCUT_ASSERT_EQUALS(7, e.p1.x);
+	PCUT_ASSERT_EQUALS(8, e.p1.y);
+}
+
+/** Rectangle envelope, a has both coordinates higher than b */
+PCUT_TEST(rect_envelope_nonempty_a_gt_b)
+{
+	gfx_rect_t a;
+	gfx_rect_t b;
+	gfx_rect_t e;
+
+	a.p0.x = 5;
+	a.p0.y = 6;
+	a.p1.x = 7;
+	a.p1.y = 8;
+
+	b.p0.x = 1;
+	b.p0.y = 2;
+	b.p1.x = 3;
+	b.p1.y = 4;
+
+	gfx_rect_envelope(&a, &b, &e);
+	PCUT_ASSERT_EQUALS(1, e.p0.x);
+	PCUT_ASSERT_EQUALS(2, e.p0.y);
+	PCUT_ASSERT_EQUALS(7, e.p1.x);
+	PCUT_ASSERT_EQUALS(8, e.p1.y);
+}
+
+/** Rectangle envelope, a is inside b */
+PCUT_TEST(rect_envelope_nonempty_a_inside_b)
+{
+	gfx_rect_t a;
+	gfx_rect_t b;
+	gfx_rect_t e;
+
+	a.p0.x = 1;
+	a.p0.y = 2;
+	a.p1.x = 7;
+	a.p1.y = 8;
+
+	b.p0.x = 3;
+	b.p0.y = 4;
+	b.p1.x = 5;
+	b.p1.y = 6;
+
+	gfx_rect_envelope(&a, &b, &e);
+	PCUT_ASSERT_EQUALS(1, e.p0.x);
+	PCUT_ASSERT_EQUALS(2, e.p0.y);
+	PCUT_ASSERT_EQUALS(7, e.p1.x);
+	PCUT_ASSERT_EQUALS(8, e.p1.y);
+}
+
+/** Rectangle envelope, b is inside a*/
+PCUT_TEST(rect_envelope_nonempty_b_inside_a)
+{
+	gfx_rect_t a;
+	gfx_rect_t b;
+	gfx_rect_t e;
+
+	a.p0.x = 3;
+	a.p0.y = 4;
+	a.p1.x = 5;
+	a.p1.y = 6;
+
+	b.p0.x = 1;
+	b.p0.y = 2;
+	b.p1.x = 7;
+	b.p1.y = 8;
+
+	gfx_rect_envelope(&a, &b, &e);
+	PCUT_ASSERT_EQUALS(1, e.p0.x);
+	PCUT_ASSERT_EQUALS(2, e.p0.y);
+	PCUT_ASSERT_EQUALS(7, e.p1.x);
+	PCUT_ASSERT_EQUALS(8, e.p1.y);
+}
+
+/** Rectangle envelope, a and b cross */
+PCUT_TEST(rect_envelope_nonempty_a_crosses_b)
+{
+	gfx_rect_t a;
+	gfx_rect_t b;
+	gfx_rect_t e;
+
+	a.p0.x = 1;
+	a.p0.y = 2;
+	a.p1.x = 4;
+	a.p1.y = 3;
+
+	b.p0.x = 2;
+	b.p0.y = 1;
+	b.p1.x = 3;
+	b.p1.y = 4;
+
+	gfx_rect_envelope(&a, &b, &e);
+	PCUT_ASSERT_EQUALS(1, e.p0.x);
+	PCUT_ASSERT_EQUALS(1, e.p0.y);
+	PCUT_ASSERT_EQUALS(4, e.p1.x);
+	PCUT_ASSERT_EQUALS(4, e.p1.y);
+}
+
+/** Sort span points that are already sorted should produde indentical points */
+PCUT_TEST(rect_points_sort_sorted)
+{
+	gfx_coord_t s0, s1;
+
+	gfx_span_points_sort(1, 2, &s0, &s1);
+	PCUT_ASSERT_EQUALS(1, s0);
+	PCUT_ASSERT_EQUALS(2, s1);
+}
+
+/** Sort span points that are reversed should transpose them */
+PCUT_TEST(rect_points_sort_reversed)
+{
+	gfx_coord_t s0, s1;
+
+	gfx_span_points_sort(2, 1, &s0, &s1);
+	PCUT_ASSERT_EQUALS(2, s0);
+	PCUT_ASSERT_EQUALS(3, s1);
+}
+
+/** gfx_rect_is_empty for straight rectangle with zero columns returns true */
+PCUT_TEST(rect_is_empty_pos_x)
+{
+	gfx_rect_t rect;
+
+	rect.p0.x = 1;
+	rect.p0.y = 2;
+	rect.p1.x = 1;
+	rect.p1.y = 3;
+	PCUT_ASSERT_TRUE(gfx_rect_is_empty(&rect));
+}
+
+/** gfx_rect_is_empty for straight rectangle with zero rows returns true */
+PCUT_TEST(rect_is_empty_pos_y)
+{
+	gfx_rect_t rect;
+
+	rect.p0.x = 1;
+	rect.p0.y = 2;
+	rect.p1.x = 2;
+	rect.p1.y = 2;
+	PCUT_ASSERT_TRUE(gfx_rect_is_empty(&rect));
+}
+
+/** gfx_rect_is_empty for staright non-empty rectangle returns false */
+PCUT_TEST(rect_is_empty_neg)
+{
+	gfx_rect_t rect;
+
+	rect.p0.x = 1;
+	rect.p0.y = 2;
+	rect.p1.x = 2;
+	rect.p1.y = 3;
+	PCUT_ASSERT_FALSE(gfx_rect_is_empty(&rect));
+}
+
+/** gfx_rect_is_empty for reverse non-empty rectangle returns false */
+PCUT_TEST(rect_is_empty_reverse_neg)
+{
+	gfx_rect_t rect;
+
+	rect.p0.x = 1;
+	rect.p0.y = 2;
+	rect.p1.x = 0;
+	rect.p1.y = 1;
+	PCUT_ASSERT_FALSE(gfx_rect_is_empty(&rect));
+}
+
 PCUT_EXPORT(coord);