Bug 1467541 - Add a test for opening the layout debugger. r=dbaron

Summary:

Reviewers: dbaron

Reviewed By: dbaron

Bug #: 1467541

Differential Revision: https://phabricator.services.mozilla.com/D2691

browser/base/content/browser-menubar.inc

@@ -544,7 +544,8 @@
                         oncommand="openPreferences(undefined, {origin: 'menubar'});"/>
 #endif
 #ifdef MOZ_DEBUG
-              <menuitem label="&ldbCmd.label;"
+              <menuitem id="menu_layout_debugger"
+                        label="&ldbCmd.label;"
                         accesskey="&ldbCmd.accesskey;"
                         oncommand="toOpenWindowByType('mozapp:layoutdebug',
                                           'chrome://layoutdebug/content/');"/>

layout/tools/layout-debug/moz.build

@@ -7,3 +7,5 @@
 DIRS += ['src', 'ui']
 
 XPCSHELL_TESTS_MANIFESTS += ['tests/unit/xpcshell.ini']
+
+BROWSER_CHROME_MANIFESTS += ['tests/browser/browser.ini']

layout/tools/layout-debug/tests/browser/browser.ini

@@ -0,0 +1,2 @@
+[browser_openLayoutDebug.js]
+run-if = debug

layout/tools/layout-debug/tests/browser/browser_openLayoutDebug.js

@@ -0,0 +1,39 @@
+"use strict";
+
+/*
+When run locally this won't test whether the files are packaged and available
+in a distributed build unless `./mach mochitest --appname dist` is used
+(after `./mach package`)
+*/
+
+function test() {
+  waitForExplicitFinish();
+
+  const windowListener = {
+    onOpenWindow(win) {
+      info("Observed window open")
+
+      const domWindow = win.docShell.domWindow;
+      waitForFocus(() => {
+        is(domWindow.location,
+           "chrome://layoutdebug/content/layoutdebug.xul",
+           "Window location is correct");
+        domWindow.close();
+      }, domWindow);
+    },
+
+    onCloseWindow() {
+      info("Observed window closed");
+      Services.wm.removeListener(this);
+      finish();
+    }
+  };
+  Services.wm.addListener(windowListener);
+
+  const menuitem = document.getElementById("menu_layout_debugger");
+  ok(menuitem, "Menuitem present");
+  if (menuitem) {
+    // open the debugger window
+    menuitem.click();
+  }
+}