diff -r 000000000000 -r 6474c204b198 browser/devtools/shadereditor/test/browser_webgl-actor-test-17.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/shadereditor/test/browser_webgl-actor-test-17.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,46 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests that the blackbox/unblackbox operations work as expected with
+ * overlapping geometry.
+ */
+
+function ifWebGLSupported() {
+  let [target, debuggee, front] = yield initBackend(OVERLAPPING_GEOMETRY_CANVAS_URL);
+  front.setup({ reload: true });
+
+  let [firstProgramActor, secondProgramActor] = yield getPrograms(front, 2);
+
+  yield ensurePixelIs(debuggee, { x: 0, y: 0 }, { r: 255, g: 255, b: 0, a: 255 }, true);
+  yield ensurePixelIs(debuggee, { x: 64, y: 64 }, { r: 0, g: 255, b: 255, a: 255 }, true);
+  yield ensurePixelIs(debuggee, { x: 127, y: 127 }, { r: 255, g: 255, b: 0, a: 255 }, true);
+  ok(true, "The corner vs. center pixel colors are correct before blackboxing.");
+
+  yield firstProgramActor.blackbox();
+  yield ensurePixelIs(debuggee, { x: 0, y: 0 }, { r: 0, g: 0, b: 0, a: 255 }, true);
+  yield ensurePixelIs(debuggee, { x: 64, y: 64 }, { r: 0, g: 255, b: 255, a: 255 }, true);
+  yield ensurePixelIs(debuggee, { x: 127, y: 127 }, { r: 0, g: 0, b: 0, a: 255 }, true);
+  ok(true, "The corner vs. center pixel colors are correct after blackboxing (1).");
+
+  yield firstProgramActor.unblackbox();
+  yield ensurePixelIs(debuggee, { x: 0, y: 0 }, { r: 255, g: 255, b: 0, a: 255 }, true);
+  yield ensurePixelIs(debuggee, { x: 64, y: 64 }, { r: 0, g: 255, b: 255, a: 255 }, true);
+  yield ensurePixelIs(debuggee, { x: 127, y: 127 }, { r: 255, g: 255, b: 0, a: 255 }, true);
+  ok(true, "The corner vs. center pixel colors are correct after unblackboxing (1).");
+
+  yield secondProgramActor.blackbox();
+  yield ensurePixelIs(debuggee, { x: 0, y: 0 }, { r: 255, g: 255, b: 0, a: 255 }, true);
+  yield ensurePixelIs(debuggee, { x: 64, y: 64 }, { r: 255, g: 255, b: 0, a: 255 }, true);
+  yield ensurePixelIs(debuggee, { x: 127, y: 127 }, { r: 255, g: 255, b: 0, a: 255 }, true);
+  ok(true, "The corner vs. center pixel colors are correct after blackboxing (2).");
+
+  yield secondProgramActor.unblackbox();
+  yield ensurePixelIs(debuggee, { x: 0, y: 0 }, { r: 255, g: 255, b: 0, a: 255 }, true);
+  yield ensurePixelIs(debuggee, { x: 64, y: 64 }, { r: 0, g: 255, b: 255, a: 255 }, true);
+  yield ensurePixelIs(debuggee, { x: 127, y: 127 }, { r: 255, g: 255, b: 0, a: 255 }, true);
+  ok(true, "The corner vs. center pixel colors are correct after unblackboxing (2).");
+
+  yield removeTab(target.tab);
+  finish();
+}