diff -r 000000000000 -r 6474c204b198 browser/devtools/inspector/test/browser_inspector_sidebarstate.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/inspector/test/browser_inspector_sidebarstate.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,72 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+let doc;
+let inspector;
+
+function createDocument()
+{
+  doc.body.innerHTML = '<h1>Sidebar state test</h1>';
+  doc.title = "Sidebar State Test";
+
+  openInspector(function(panel) {
+    inspector = panel;
+    inspector.sidebar.select("ruleview");
+    inspectorRuleViewOpened();
+  });
+}
+
+function inspectorRuleViewOpened()
+{
+  is(inspector.sidebar.getCurrentTabID(), "ruleview", "Rule View is selected by default");
+
+  // Select the computed view and turn off the inspector.
+  inspector.sidebar.select("computedview");
+
+  gDevTools.once("toolbox-destroyed", inspectorClosed);
+  let target = TargetFactory.forTab(gBrowser.selectedTab);
+  gDevTools.closeToolbox(target);
+}
+
+function inspectorClosed()
+{
+  openInspector(function(panel) {
+    inspector = panel;
+
+    if (inspector.sidebar.getCurrentTabID()) {
+      info("Default sidebar already selected.")
+      testNewDefaultTab();
+    } else {
+      info("Default sidebar still to be selected, adding select listener.");
+      inspector.sidebar.once("select", testNewDefaultTab);
+    }
+  });
+}
+
+function testNewDefaultTab()
+{
+  is(inspector.sidebar.getCurrentTabID(), "computedview", "Computed view is selected by default.");
+
+  finishTest();
+}
+
+
+function finishTest()
+{
+  doc = inspector = null;
+  gBrowser.removeCurrentTab();
+  finish();
+}
+
+function test()
+{
+  waitForExplicitFinish();
+  gBrowser.selectedTab = gBrowser.addTab();
+  gBrowser.selectedBrowser.addEventListener("load", function() {
+    gBrowser.selectedBrowser.removeEventListener("load", arguments.callee, true);
+    doc = content.document;
+    waitForFocus(createDocument, content);
+  }, true);
+
+  content.location = "data:text/html;charset=utf-8,browser_inspector_sidebarstate.js";
+}