diff -r 000000000000 -r 6474c204b198 browser/devtools/debugger/test/browser_dbg_scripts-switching-03.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/debugger/test/browser_dbg_scripts-switching-03.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,52 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Make sure that the DebuggerView error loading source text is correct.
+ */
+
+const TAB_URL = EXAMPLE_URL + "doc_script-switching-01.html";
+
+let gTab, gDebuggee, gPanel, gDebugger;
+let gView, gEditor, gL10N;
+
+function test() {
+  initDebugger(TAB_URL).then(([aTab, aDebuggee, aPanel]) => {
+    gTab = aTab;
+    gDebuggee = aDebuggee;
+    gPanel = aPanel;
+    gDebugger = gPanel.panelWin;
+    gView = gDebugger.DebuggerView;
+    gEditor = gDebugger.DebuggerView.editor;
+    gL10N = gDebugger.L10N;
+
+    waitForSourceShown(gPanel, "-01.js")
+      .then(showBogusSource)
+      .then(testDebuggerLoadingError)
+      .then(() => closeDebuggerAndFinish(gPanel))
+      .then(null, aError => {
+        ok(false, "Got an error: " + aError.message + "\n" + aError.stack);
+      });
+  });
+}
+
+function showBogusSource() {
+  let finished = waitForDebuggerEvents(gPanel, gDebugger.EVENTS.SOURCE_ERROR_SHOWN);
+  gView._setEditorSource({ url: "http://example.com/fake.js", actor: "fake.actor" });
+  return finished;
+}
+
+function testDebuggerLoadingError() {
+  ok(gEditor.getText().contains(gL10N.getStr("errorLoadingText")),
+    "The valid error loading message is displayed.");
+}
+
+registerCleanupFunction(function() {
+  gTab = null;
+  gDebuggee = null;
+  gPanel = null;
+  gDebugger = null;
+  gView = null;
+  gEditor = null;
+  gL10N = null;
+});