diff -r 000000000000 -r 6474c204b198 browser/devtools/netmonitor/test/browser_net_json-long.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/netmonitor/test/browser_net_json-long.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,91 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests if very long JSON responses are handled correctly.
+ */
+
+function test() {
+  initNetMonitor(JSON_LONG_URL).then(([aTab, aDebuggee, aMonitor]) => {
+    info("Starting test... ");
+
+    // This is receiving over 80 KB of json and will populate over 6000 items
+    // in a variables view instance. Debug builds are slow.
+    requestLongerTimeout(4);
+
+    let { document, L10N, NetMonitorView } = aMonitor.panelWin;
+    let { RequestsMenu } = NetMonitorView;
+
+    RequestsMenu.lazyUpdate = false;
+
+    waitForNetworkEvents(aMonitor, 1).then(() => {
+      verifyRequestItemTarget(RequestsMenu.getItemAtIndex(0),
+        "GET", CONTENT_TYPE_SJS + "?fmt=json-long", {
+          status: 200,
+          statusText: "OK",
+          type: "json",
+          fullMimeType: "text/json; charset=utf-8",
+          size: L10N.getFormatStr("networkMenu.sizeKB", L10N.numberWithDecimals(85975/1024, 2)),
+          time: true
+        });
+
+      aMonitor.panelWin.once(aMonitor.panelWin.EVENTS.RESPONSE_BODY_DISPLAYED, () => {
+        testResponseTab();
+        teardown(aMonitor).then(finish);
+      });
+
+      EventUtils.sendMouseEvent({ type: "mousedown" },
+        document.getElementById("details-pane-toggle"));
+      EventUtils.sendMouseEvent({ type: "mousedown" },
+        document.querySelectorAll("#details-pane tab")[3]);
+
+      function testResponseTab() {
+        let tab = document.querySelectorAll("#details-pane tab")[3];
+        let tabpanel = document.querySelectorAll("#details-pane tabpanel")[3];
+
+        is(tab.getAttribute("selected"), "true",
+          "The response tab in the network details pane should be selected.");
+
+        is(tabpanel.querySelector("#response-content-info-header")
+          .hasAttribute("hidden"), true,
+          "The response info header doesn't have the intended visibility.");
+        is(tabpanel.querySelector("#response-content-json-box")
+          .hasAttribute("hidden"), false,
+          "The response content json box doesn't have the intended visibility.");
+        is(tabpanel.querySelector("#response-content-textarea-box")
+          .hasAttribute("hidden"), true,
+          "The response content textarea box doesn't have the intended visibility.");
+        is(tabpanel.querySelector("#response-content-image-box")
+          .hasAttribute("hidden"), true,
+          "The response content image box doesn't have the intended visibility.");
+
+        is(tabpanel.querySelectorAll(".variables-view-scope").length, 1,
+          "There should be 1 json scope displayed in this tabpanel.");
+        is(tabpanel.querySelectorAll(".variables-view-property").length, 6143,
+          "There should be 6143 json properties displayed in this tabpanel.");
+        is(tabpanel.querySelectorAll(".variables-view-empty-notice").length, 0,
+          "The empty notice should not be displayed in this tabpanel.");
+
+        let jsonScope = tabpanel.querySelectorAll(".variables-view-scope")[0];
+        let names = ".variables-view-property > .title > .name";
+        let values = ".variables-view-property > .title > .value";
+
+        is(jsonScope.querySelector(".name").getAttribute("value"),
+          L10N.getStr("jsonScopeName"),
+          "The json scope doesn't have the correct title.");
+
+        is(jsonScope.querySelectorAll(names)[0].getAttribute("value"),
+          "0", "The first json property name was incorrect.");
+        is(jsonScope.querySelectorAll(values)[0].getAttribute("value"),
+          "Object", "The first json property value was incorrect.");
+
+        is(jsonScope.querySelectorAll(names)[1].getAttribute("value"),
+          "greeting", "The second json property name was incorrect.");
+        is(jsonScope.querySelectorAll(values)[1].getAttribute("value"),
+          "\"Hello long string JSON!\"", "The second json property value was incorrect.");
+      }
+    });
+
+    aDebuggee.performRequests();
+  });
+}