Fixing testBrowsingPostEntryWithButton flakiness.

ios/chrome/browser/web/forms_egtest.mm

 // Copyright 2016 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.
 
 #import <XCTest/XCTest.h>
 
 #include "base/mac/scoped_nsobject.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/sys_string_conversions.h"
 #include "components/strings/grit/components_strings.h"
 #import "ios/chrome/browser/ui/commands/generic_chrome_command.h"
 #include "ios/chrome/browser/ui/commands/ios_command_ids.h"
 #include "ios/chrome/browser/ui/ui_util.h"
 #import "ios/chrome/test/app/chrome_test_util.h"
 #include "ios/chrome/test/app/navigation_test_util.h"
 #include "ios/chrome/test/app/web_view_interaction_test_util.h"
 #import "ios/chrome/test/earl_grey/chrome_earl_grey.h"
 #import "ios/chrome/test/earl_grey/chrome_matchers.h"
 #import "ios/chrome/test/earl_grey/chrome_test_case.h"
 #import "ios/testing/wait_util.h"
 #import "ios/web/public/test/http_server.h"
 #import "ios/web/public/test/http_server_util.h"
 #include "ios/web/public/test/response_providers/data_response_provider.h"
 #include "ios/web/public/test/url_test_util.h"
 
+using chrome_test_util::OmniboxText;
+using chrome_test_util::WebViewContainingText;
+
 namespace {
 
 // URL for a generic website in the user navigation flow.
 const char kGenericUrl[] = "http://generic";
 
 // URL to print the HTTP method and the request body.
 const char kPrintFormDataUrl[] = "http://printFormData";
 
 // URL that redirects to kPrintPostData with a 302.
 const char kRedirectUrl[] = "http://redirect";
@@ skipping 80 matching lines @@
     return;
   } else if (url == TestResponseProvider::GetPrintFormDataUrl()) {
     *response_body = request.method + std::string(" ") + request.body;
     return;
   }
   NOTREACHED();
 }
 
 }  // namespace
 
-using chrome_test_util::OmniboxText;
-
 // Tests submition of HTTP forms POST data including cases involving navigation.
 @interface FormsTestCase : ChromeTestCase
 @end
 
 @implementation FormsTestCase
 
 // Sets up server urls and responses.
 - (void)setUp {
   [super setUp];
 
@@ skipping 200 matching lines @@
   // Check that the popup did not show
   id<GREYMatcher> resendWarning =
       chrome_test_util::ButtonWithAccessibilityLabelId(
           IDS_HTTP_POST_WARNING_RESEND);
   [[EarlGrey selectElementWithMatcher:resendWarning]
       assertWithMatcher:grey_nil()];
 
   [self waitForExpectedResponse:"GET"];
 }
 
+// Tests that pressing the button on a POST-based form changes the page and that
+// the back button works as expected afterwards.
+- (void)testGoBackButtonAfterFormSubmission {
+  GURL formURL = TestResponseProvider::GetFormUrl();
+  GURL destinationURL = TestResponseProvider::GetPrintFormDataUrl();
+
+  [ChromeEarlGrey loadURL:formURL];
+  chrome_test_util::TapWebViewElementWithId(kSubmitButton);
+  [[EarlGrey selectElementWithMatcher:WebViewContainingText(kExpectedPostData)]

[gchatz, 2017/04/10 18:43:23]

Should this use [self waitForExpectedResponse]?

[liaoyuke, 2017/04/10 18:48:09]

I think we should remove this method (in a separate CL). 

WebViewContainingText is a matcher that waits, and it will be refactored to
[ChromeEarlGrey waitForWebViewContainingText] some time in the future, so
removing [self waitForExpectedResponse] will make things easier and cleaner.

[gchatz, 2017/04/10 20:46:10]

Ok sounds good

[Eugene But (OOO till 7-30), 2017/04/10 20:46:45]

Could you please file a bug and add a TODO for this. Unless you plan a follow up
CL.

+      assertWithMatcher:grey_notNil()];
+  [[EarlGrey selectElementWithMatcher:OmniboxText(destinationURL.GetContent())]
+      assertWithMatcher:grey_notNil()];
+
+  // Go back and verify the browser navigates to the original URL.
+  [self goBack];
+  [[EarlGrey selectElementWithMatcher:WebViewContainingText("Unicorn")]
+      assertWithMatcher:grey_notNil()];
+  [[EarlGrey selectElementWithMatcher:OmniboxText(formURL.GetContent())]
+      assertWithMatcher:grey_notNil()];
+}
+
 @end