Refactor PostOnSamePage test to ensure the form is posted.

ios/chrome/browser/web/browsing_egtest.mm

Index: ios/chrome/browser/web/browsing_egtest.mm
diff --git a/ios/chrome/browser/web/browsing_egtest.mm b/ios/chrome/browser/web/browsing_egtest.mm
index ac51f9bc840fb67d3533341e4f40865f76fa4d99..6f9a75a3821212634e639116dbda654cb128af0b 100644
--- a/ios/chrome/browser/web/browsing_egtest.mm
+++ b/ios/chrome/browser/web/browsing_egtest.mm
@@ -45,6 +45,8 @@ namespace {
 
 // URL used for the reload test.
 const char kReloadTestUrl[] = "http://mock/reloadTest";
+const char kFormPageUrl[] = "http://form/";
+const char kFirstPageUrl[] = "http://first/";
 
 // Returns the number of serviced requests in HTTP body.
 class ReloadResponseProvider : public web::DataResponseProvider {
@@ -78,6 +80,43 @@ class ReloadResponseProvider : public web::DataResponseProvider {
   int request_number_;  // Count of requests received by the response provider.
 };
 
+// A ResponseProvider that provides post form on the same page.
+class TestPostFormResponseProvider : public web::DataResponseProvider {

[Eugene But (OOO till 7-30), 2017/06/24 00:26:09]

Looks like forms_egtest has a response provider that prints HPPT method. Can we
reuse that existing code? Moving |testBrowsingPostToSamePage| to forms_egtest
sounds like a reasonable direction.

+ public:
+  // URLs used for the post form test.
+  static GURL GetFirstPageUrl() {
+    return web::test::HttpServer::MakeUrl(kFirstPageUrl);
+  }
+  static GURL GetFormPageUrl() {
+    return web::test::HttpServer::MakeUrl(kFormPageUrl);
+  }
+
+  bool CanHandleRequest(const Request& request) override {
+    return request.url == GetFormPageUrl() || request.url == GetFirstPageUrl();
+  }
+  void GetResponseHeadersAndBody(
+      const Request& request,
+      scoped_refptr<net::HttpResponseHeaders>* headers,
+      std::string* response_body) override {
+    const GURL& url = request.url;
+    *headers = web::ResponseProvider::GetDefaultResponseHeaders();
+    if (url == GetFirstPageUrl()) {
+      *response_body = "foo";
+      return;
+    } else if (url == GetFormPageUrl()) {
+      if (request.method == "POST") {
+        *response_body = request.method + std::string(" ") + request.body;
+      } else {
+        *response_body =
+            "<form method='post'>"
+            "<input value='button' type='submit' id='button'></form>";
+      }
+      return;
+    }
+    NOTREACHED();
+  }
+};
+
 // ScopedBlockPopupsPref modifies the block popups preference and resets the
 // preference to its original value when this object goes out of scope.
 // TODO(crbug.com/638674): Evaluate if this can move to shared code
@@ -436,7 +475,7 @@ id<GREYMatcher> GoButtonMatcher() {
 }
 
 // Tests that pressing the button on a POST-based form with same-page action
-// does not change the page and that the back button works as expected
+// does not change the page URL and that the back button works as expected
 // afterwards.
 - (void)testBrowsingPostToSamePage {
 // TODO(crbug.com/714303): Re-enable this test on devices.
@@ -444,17 +483,12 @@ id<GREYMatcher> GoButtonMatcher() {
   EARL_GREY_TEST_DISABLED(@"Test disabled on device.");
 #endif
 
-  // Create map of canned responses and set up the test HTML server.
-  std::map<GURL, std::string> responses;
-  const GURL firstURL = web::test::HttpServer::MakeUrl("http://first");
-  const GURL formURL = web::test::HttpServer::MakeUrl("http://form");
-  // This is just a page with some text.
-  responses[firstURL] = "foo";
-  // This is a page with at button that posts to the current URL.
-  responses[formURL] =
-      "<form method='post'>"
-      "<input value='button' type='submit' id='button'></form>";
-  web::test::SetUpSimpleHttpServer(responses);
+  // Set up test HTTP server responses.
+  std::unique_ptr<web::DataResponseProvider> provider(
+      new TestPostFormResponseProvider());
+  web::test::SetUpHttpServer(std::move(provider));
+  const GURL firstURL = TestPostFormResponseProvider::GetFirstPageUrl();
+  const GURL formURL = TestPostFormResponseProvider::GetFormPageUrl();
 
   // Open the first URL so it's in history.
   [ChromeEarlGrey loadURL:firstURL];
@@ -463,6 +497,7 @@ id<GREYMatcher> GoButtonMatcher() {
   // the expected URL.
   [ChromeEarlGrey loadURL:formURL];
   chrome_test_util::TapWebViewElementWithId("button");
+  [ChromeEarlGrey waitForWebViewContainingText:"POST"];
   [[EarlGrey selectElementWithMatcher:OmniboxText(formURL.GetContent())]
       assertWithMatcher:grey_notNil()];