Bug 1575341 - WebSocket Inspector Test: Limit number of frames. r=Honza

Test that the truncated message notification displays correctly.

Differential Revision: https://phabricator.services.mozilla.com/D42719

--HG--
extra : moz-landing-system : lando

devtools/client/netmonitor/test/browser.ini

@@ -238,4 +238,5 @@ skip-if = (os == 'win' && os_version == '6.1' && !debug) # Bug 1547150
 [browser_net_ws-basic.js]
 [browser_net_ws-clear.js]
 [browser_net_ws-filter-dropdown.js]
+[browser_net_ws-limit-frames.js]
 [browser_net-ws-filter-freetext.js]

devtools/client/netmonitor/test/browser_net_ws-limit-frames.js

@@ -0,0 +1,64 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Test that WS connection is established successfully and the truncated message notification displays correctly.
+ */
+
+add_task(async function() {
+  await pushPref("devtools.netmonitor.features.webSockets", true);
+
+  // Set WS frames limit to a lower value for testing
+  await pushPref("devtools.netmonitor.ws.displayed-frames.limit", 30);
+
+  const { tab, monitor } = await initNetMonitor(WS_PAGE_URL);
+  info("Starting test... ");
+
+  const { document, store, windowRequire } = monitor.panelWin;
+  const Actions = windowRequire("devtools/client/netmonitor/src/actions/index");
+
+  store.dispatch(Actions.batchEnable(false));
+
+  // Wait for WS connections to be established + send messages
+  await ContentTask.spawn(tab.linkedBrowser, {}, async () => {
+    await content.wrappedJSObject.openConnection(20);
+  });
+
+  const requests = document.querySelectorAll(".request-list-item");
+  is(requests.length, 1, "There should be one request");
+
+  // Wait for truncated message notification to appear
+  wait = waitForDOM(document, "#messages-panel .truncated-message");
+
+  // Select the first request
+  EventUtils.sendMouseEvent({ type: "mousedown" }, requests[0]);
+
+  // Click on the "Messages" panel
+  EventUtils.sendMouseEvent(
+    { type: "click" },
+    document.querySelector("#messages-tab")
+  );
+  await wait;
+
+  // Get all messages present in the "Messages" panel
+  const frames = document.querySelectorAll(
+    "#messages-panel .ws-frames-list-table .ws-frame-list-item"
+  );
+
+  // Check expected results
+  is(frames.length, 30, "There should be thirty frames");
+  is(
+    document.querySelectorAll("#messages-panel .truncated-message").length,
+    1,
+    "Truncated message notification is shown"
+  );
+
+  // Close WS connection
+  await ContentTask.spawn(tab.linkedBrowser, {}, async () => {
+    await content.wrappedJSObject.closeConnection();
+  });
+
+  await teardown(monitor);
+});