Bug 1570524 - Fix browser_webconsole_cached_messages intermittent. r=Honza.

Wait for the messages to be displayed, and requestLongerTimeout,
as test failures logs seem to indicate that slower machine take
more than 30s to run the test.

Differential Revision: https://phabricator.services.mozilla.com/D51562

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

devtools/client/webconsole/test/browser/browser_webconsole_cached_messages.js

@@ -1,15 +1,16 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
-// Test to see if the cached messages are displayed when the console UI is
-// opened.
+// Test to see if the cached messages are displayed when the console UI is opened.
 
 "use strict";
 
+// See Bug 1570524.
+requestLongerTimeout(2);
+
 const TEST_URI =
   "http://example.com/browser/devtools/client/webconsole/" +
-  "test/browser/" +
-  "test-webconsole-error-observer.html";
+  "test/browser/test-webconsole-error-observer.html";
 
 add_task(async function() {
   // On e10s, the exception is triggered in child process
@@ -25,31 +26,36 @@ add_task(async function() {
   info("Open the console");
   let hud = await openConsole();
 
-  await testMessagesVisibility(hud, true);
+  await testMessagesVisibility(hud);
 
   info("Close the toolbox");
   await closeToolbox();
 
   info("Open the console again");
   hud = await openConsole();
-  await testMessagesVisibility(hud, false);
+  await testMessagesVisibility(hud);
 });
 
-async function testMessagesVisibility(hud, waitForCSSMessage) {
-  let message = findMessage(hud, "log Bazzle", ".message.log");
+async function testMessagesVisibility(hud) {
+  let message = await waitFor(() =>
+    findMessage(hud, "log Bazzle", ".message.log")
+  );
   ok(message, "console.log message is visible");
 
-  message = findMessage(hud, "error Bazzle", ".message.error");
+  message = await waitFor(() =>
+    findMessage(hud, "error Bazzle", ".message.error")
+  );
   ok(message, "console.error message is visible");
 
-  message = findMessage(hud, "bazBug611032", ".message.error");
+  message = await waitFor(() =>
+    findMessage(hud, "bazBug611032", ".message.error")
+  );
   ok(message, "exception message is visible");
 
   // The CSS message arrives lazily, so spin a bit for it unless it should be
   // cached.
-  if (waitForCSSMessage) {
-    await waitForMessage(hud, "cssColorBug611032");
-  }
-  message = findMessage(hud, "cssColorBug611032", ".message.warn.css");
+  message = await waitFor(() =>
+    findMessage(hud, "cssColorBug611032", ".message.warn.css")
+  );
   ok(message, "css warning message is visible");
 }