diff -r 000000000000 -r 6474c204b198 browser/devtools/netmonitor/test/browser_net_pane-toggle.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/netmonitor/test/browser_net_pane-toggle.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,79 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests if toggling the details pane works as expected.
+ */
+
+function test() {
+  initNetMonitor(SIMPLE_URL).then(([aTab, aDebuggee, aMonitor]) => {
+    info("Starting test... ");
+
+    let { document, NetMonitorView } = aMonitor.panelWin;
+    let { RequestsMenu } = NetMonitorView;
+
+    RequestsMenu.lazyUpdate = false;
+
+    is(document.querySelector("#details-pane-toggle")
+      .hasAttribute("disabled"), true,
+      "The pane toggle button should be disabled when the frontend is opened.");
+    is(document.querySelector("#details-pane-toggle")
+      .hasAttribute("pane-collapsed"), true,
+      "The pane toggle button should indicate that the details pane is " +
+      "collapsed when the frontend is opened.");
+    is(NetMonitorView.detailsPaneHidden, true,
+      "The details pane should be hidden when the frontend is opened.");
+    is(RequestsMenu.selectedItem, null,
+      "There should be no selected item in the requests menu.");
+
+    aMonitor.panelWin.once(aMonitor.panelWin.EVENTS.NETWORK_EVENT, () => {
+      is(document.querySelector("#details-pane-toggle")
+        .hasAttribute("disabled"), false,
+        "The pane toggle button should be enabled after the first request.");
+      is(document.querySelector("#details-pane-toggle")
+        .hasAttribute("pane-collapsed"), true,
+        "The pane toggle button should still indicate that the details pane is " +
+        "collapsed after the first request.");
+      is(NetMonitorView.detailsPaneHidden, true,
+        "The details pane should still be hidden after the first request.");
+      is(RequestsMenu.selectedItem, null,
+        "There should still be no selected item in the requests menu.");
+
+      EventUtils.sendMouseEvent({ type: "mousedown" },
+        document.getElementById("details-pane-toggle"));
+
+      is(document.querySelector("#details-pane-toggle")
+        .hasAttribute("disabled"), false,
+        "The pane toggle button should still be enabled after being pressed.");
+      is(document.querySelector("#details-pane-toggle")
+        .hasAttribute("pane-collapsed"), false,
+        "The pane toggle button should now indicate that the details pane is " +
+        "not collapsed anymore after being pressed.");
+      is(NetMonitorView.detailsPaneHidden, false,
+        "The details pane should not be hidden after toggle button was pressed.");
+      isnot(RequestsMenu.selectedItem, null,
+        "There should be a selected item in the requests menu.");
+      is(RequestsMenu.selectedIndex, 0,
+        "The first item should be selected in the requests menu.");
+
+      EventUtils.sendMouseEvent({ type: "mousedown" },
+        document.getElementById("details-pane-toggle"));
+
+      is(document.querySelector("#details-pane-toggle")
+        .hasAttribute("disabled"), false,
+        "The pane toggle button should still be enabled after being pressed again.");
+      is(document.querySelector("#details-pane-toggle")
+        .hasAttribute("pane-collapsed"), true,
+        "The pane toggle button should now indicate that the details pane is " +
+        "collapsed after being pressed again.");
+      is(NetMonitorView.detailsPaneHidden, true,
+        "The details pane should now be hidden after the toggle button was pressed again.");
+      is(RequestsMenu.selectedItem, null,
+        "There should now be no selected item in the requests menu.");
+
+      teardown(aMonitor).then(finish);
+    });
+
+    aDebuggee.location.reload();
+  });
+}