diff -r 000000000000 -r 6474c204b198 browser/devtools/netmonitor/test/browser_net_json-malformed.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/netmonitor/test/browser_net_json-malformed.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,74 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests if malformed JSON responses are handled correctly.
+ */
+
+function test() {
+  initNetMonitor(JSON_MALFORMED_URL).then(([aTab, aDebuggee, aMonitor]) => {
+    info("Starting test... ");
+
+    let { document, Editor, NetMonitorView } = aMonitor.panelWin;
+    let { RequestsMenu } = NetMonitorView;
+
+    RequestsMenu.lazyUpdate = false;
+
+    waitForNetworkEvents(aMonitor, 1).then(() => {
+      verifyRequestItemTarget(RequestsMenu.getItemAtIndex(0),
+        "GET", CONTENT_TYPE_SJS + "?fmt=json-malformed", {
+          status: 200,
+          statusText: "OK",
+          type: "json",
+          fullMimeType: "text/json; charset=utf-8"
+        });
+
+      EventUtils.sendMouseEvent({ type: "mousedown" },
+        document.getElementById("details-pane-toggle"));
+      EventUtils.sendMouseEvent({ type: "mousedown" },
+        document.querySelectorAll("#details-pane tab")[3]);
+
+      let tab = document.querySelectorAll("#details-pane tab")[3];
+      let tabpanel = document.querySelectorAll("#details-pane tabpanel")[3];
+
+      let RESPONSE_BODY_DISPLAYED = aMonitor.panelWin.EVENTS.RESPONSE_BODY_DISPLAYED;
+      waitFor(aMonitor.panelWin, RESPONSE_BODY_DISPLAYED).then(() => {
+        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"), false,
+          "The response info header doesn't have the intended visibility.");
+        is(tabpanel.querySelector("#response-content-info-header")
+          .getAttribute("value"),
+          "SyntaxError: JSON.parse: unexpected non-whitespace character after JSON data at line 1 column 40 of the JSON data",
+          "The response info header doesn't have the intended value attribute.");
+        is(tabpanel.querySelector("#response-content-info-header")
+          .getAttribute("tooltiptext"),
+          "SyntaxError: JSON.parse: unexpected non-whitespace character after JSON data at line 1 column 40 of the JSON data",
+          "The response info header doesn't have the intended tooltiptext attribute.");
+
+        is(tabpanel.querySelector("#response-content-json-box")
+          .hasAttribute("hidden"), true,
+          "The response content json box doesn't have the intended visibility.");
+        is(tabpanel.querySelector("#response-content-textarea-box")
+          .hasAttribute("hidden"), false,
+          "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.");
+
+        NetMonitorView.editor("#response-content-textarea").then((aEditor) => {
+          is(aEditor.getText(), "{ \"greeting\": \"Hello malformed JSON!\" },",
+            "The text shown in the source editor is incorrect.");
+          is(aEditor.getMode(), Editor.modes.js,
+            "The mode active in the source editor is incorrect.");
+
+          teardown(aMonitor).then(finish);
+        });
+      });
+    });
+
+    aDebuggee.performRequests();
+  });
+}