Refactor Assert[No]CookieExists to return a boolean

ios/chrome/browser/ui/settings/settings_egtest.mm

Index: ios/chrome/browser/ui/settings/settings_egtest.mm
diff --git a/ios/chrome/browser/ui/settings/settings_egtest.mm b/ios/chrome/browser/ui/settings/settings_egtest.mm
index 2c18971ac806df1614f158ad74af625b82deeb4c..778d672495f5c0bef3b63931e1f93814cae7e712 100644
--- a/ios/chrome/browser/ui/settings/settings_egtest.mm
+++ b/ios/chrome/browser/ui/settings/settings_egtest.mm
@@ -164,27 +164,32 @@
   return ButtonWithAccessibilityLabelId(IDS_IOS_PASSWORD_MANAGER_SAVE_BUTTON);
 }
 
-// Asserts that there is no cookie in current web state.
-void AssertNoCookieExists() {
-  NSError* error = nil;
+// Returns true if there is no cookie in current web state.
+bool WebStateHasNoCookie() {
   chrome_test_util::ExecuteJavaScript(
-      base::SysUTF8ToNSString(kJavaScriptGetCookies), &error);
+      base::SysUTF8ToNSString(kJavaScriptGetCookies), nil);
+  NSError* error = nil;
   [[EarlGrey selectElementWithMatcher:chrome_test_util::WebViewContainingText(
                                           kNoCookieText)]
-      assertWithMatcher:grey_notNil()];
+      assertWithMatcher:grey_notNil()
+                  error:&error];
+
+  return error == nil;
 }
 
-// Asserts |cookie| exists in current web state.
-void AssertCookieExists(const char cookie[]) {
-  NSError* error = nil;
+// Returns true if |cookie| is the only cookie exists in current web state.

[baxley, 2017/03/08 16:20:50]

will this return true if it's the "only" cookie? Is there a way to have multiple
cookies and it return true?

[liaoyuke, 2017/03/08 21:27:26]

Resolved per offline discussion.

+bool WebStateHasCookie(const char cookie[]) {
   chrome_test_util::ExecuteJavaScript(
-      base::SysUTF8ToNSString(kJavaScriptGetCookies), &error);
+      base::SysUTF8ToNSString(kJavaScriptGetCookies), nil);
   NSString* const expectedCookieText =
       [NSString stringWithFormat:@"OK: %@", base::SysUTF8ToNSString(cookie)];
+  NSError* error = nil;
   [[EarlGrey
       selectElementWithMatcher:chrome_test_util::WebViewContainingText(
                                    base::SysNSStringToUTF8(expectedCookieText))]
-      assertWithMatcher:grey_notNil()];
+      assertWithMatcher:grey_notNil()
+                  error:&error];

[baxley, 2017/03/08 16:20:50]

Sorry, I'm not great at reading regex. Could you clarify why this would return
false for the case where there are two cookies, and we're checking for the first
one?

[liaoyuke, 2017/03/08 21:27:26]

Resolved per offline discussion.

+  return error == nil;
 }
 
 // Run as a task to check if a certificate has been added to the ChannelIDStore.
@@ -687,7 +692,9 @@ - (void)testClearCookies {
   [[EarlGrey selectElementWithMatcher:chrome_test_util::WebViewContainingText(
                                           kResponse)]
       assertWithMatcher:grey_notNil()];
-  AssertNoCookieExists();
+
+  GREYAssertTrue(WebStateHasNoCookie(),
+                 @"Web state is expected to have no cookie.");
 
   // Visit |kUrlWithSetCookie| to set a cookie and then load |kUrl| to check it
   // is still set.
@@ -700,7 +707,10 @@ - (void)testClearCookies {
                                           kResponse)]
       assertWithMatcher:grey_notNil()];
 
-  AssertCookieExists(kCookie);
+  NSString* const errorMessage = [NSString
+      stringWithFormat:@"Web state is expected to have following cookie: %@.",
+                       base::SysUTF8ToNSString(kCookie)];
+  GREYAssertTrue(WebStateHasCookie(kCookie), errorMessage);
 
   // Restore the Clear Browsing Data checkmarks prefs to their default state in
   // Teardown.
@@ -716,7 +726,8 @@ - (void)testClearCookies {
   [[EarlGrey selectElementWithMatcher:chrome_test_util::WebViewContainingText(
                                           kResponse)]
       assertWithMatcher:grey_notNil()];
-  AssertNoCookieExists();
+  GREYAssertTrue(WebStateHasNoCookie(),
+                 @"Web state is expected to have no cookie.");
   chrome_test_util::CloseAllTabs();
 }