ChromeOS Web UI Tests: make WebUIBrowserTest error message more readable.

chrome/test/base/web_ui_browser_test.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/test/base/web_ui_browser_test.h"
 
 #include <stddef.h>
 
 #include <string>
 #include <vector>
@@ skipping 441 matching lines @@
     test_handler_->PreloadJavaScript(libraries[i], preload_host);
 
   if (is_test)
     result = test_handler_->RunJavaScriptTestWithResult(content);
   else if (preload_host)
     test_handler_->PreloadJavaScript(content, preload_host);
   else
     test_handler_->RunJavaScript(content);
 
   if (error_messages_.Get().size() > 0) {
-    LOG(ERROR) << "Encountered javascript console error(s)";
+    LOG(ERROR) << "CONDITION FAILURE: encountered javascript console error(s):";
+    for (const auto& msg : error_messages_.Get()) {
+      LOG(ERROR) << "JS ERROR: '" << msg << "'";

[michaelpg, 2016/07/29 22:38:29]

Do you not normally see console errors when your tests fail? I'm seeing
duplicate errors now because they're logged first during the test, and then
again at the end here. That's annoying IMO -- is this WAI?

+    }
+    LOG(ERROR) << "JS call assumed failed, because JS console error(s) found.";
+
     result = false;
     error_messages_.Get().clear();
   }
   return result;
 }
 
 void WebUIBrowserTest::SetupHandlers() {
   content::WebUI* web_ui_instance =
       override_selected_web_ui_
           ? override_selected_web_ui_
@@ skipping 10 matching lines @@
 }
 
 GURL WebUIBrowserTest::WebUITestDataPathToURL(
     const base::FilePath::StringType& path) {
   base::FilePath dir_test_data;
   EXPECT_TRUE(PathService::Get(chrome::DIR_TEST_DATA, &dir_test_data));
   base::FilePath test_path(dir_test_data.Append(kWebUITestFolder).Append(path));
   EXPECT_TRUE(base::PathExists(test_path));
   return net::FilePathToFileURL(test_path);
 }