diff -r 000000000000 -r 6474c204b198 browser/devtools/debugger/test/browser_dbg_blackboxing-02.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/debugger/test/browser_dbg_blackboxing-02.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,59 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Test that black boxed frames are compressed into a single frame on the stack
+ * view.
+ */
+
+const TAB_URL = EXAMPLE_URL + "doc_blackboxing.html";
+const BLACKBOXME_URL = EXAMPLE_URL + "code_blackboxing_blackboxme.js"
+
+let gTab, gDebuggee, gPanel, gDebugger;
+let gFrames;
+
+function test() {
+  initDebugger(TAB_URL).then(([aTab, aDebuggee, aPanel]) => {
+    gTab = aTab;
+    gDebuggee = aDebuggee;
+    gPanel = aPanel;
+    gDebugger = gPanel.panelWin;
+    gFrames = gDebugger.DebuggerView.StackFrames;
+
+    waitForSourceShown(gPanel, BLACKBOXME_URL)
+      .then(testBlackBoxSource)
+      .then(testBlackBoxStack)
+      .then(() => resumeDebuggerThenCloseAndFinish(gPanel))
+      .then(null, aError => {
+        ok(false, "Got an error: " + aError.message + "\n" + aError.stack);
+      });
+  });
+}
+
+function testBlackBoxSource() {
+  return toggleBlackBoxing(gPanel).then(aSource => {
+    ok(aSource.isBlackBoxed, "The source should be black boxed now.");
+  });
+}
+
+function testBlackBoxStack() {
+  let finished = waitForSourceAndCaretAndScopes(gPanel, ".html", 21).then(() => {
+    is(gFrames.itemCount, 3,
+      "Should only get 3 frames.");
+    is(gDebugger.document.querySelectorAll(".dbg-stackframe-black-boxed").length, 1,
+      "And one of them should be the combined black boxed frames.");
+  });
+
+  // Spin the event loop before causing the debuggee to pause, to allow
+  // this function to return first.
+  executeSoon(() => gDebuggee.runTest());
+  return finished;
+}
+
+registerCleanupFunction(function() {
+  gTab = null;
+  gDebuggee = null;
+  gPanel = null;
+  gDebugger = null;
+  gFrames = null;
+});