Move GREYAsserts from tab_usage_recorder_test_util into the corresponding EG test.

This is part of EG1 to EG2 migration, which involves moving EarlGrey code from
app-side helpers into test code. For GREYAsserts, the policy is to take assert-
containing-helpers, modify them to return NSError* with localizedDescription
containing the assert failure (in the event of a failure), and then assert
on the result of the helper on the test side.

I add a new helper which assists in creating NSErrors.

Bug: 922813
Change-Id: Ib2fc2bb0b016afc416ccbbdae19c4acbcaf48350
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1553085
Commit-Queue: ericale <ericale@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#649718}

ios/chrome/browser/metrics/tab_usage_recorder_egtest.mm

@@ -150,12 +150,17 @@ void CloseTabAtIndexAndSync(NSUInteger i) {
       kSelectedTabHistogramName, TabUsageRecorder::IN_MEMORY, 1, failureBlock);
 
   // Evict the tab.
-  OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  NSError* openError = OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  GREYAssertNil(openError, openError.localizedDescription);
+
   GREYAssertTrue(chrome_test_util::IsIncognitoMode(),
                  @"Failed to switch to incognito mode");
 
   // Switch back to the normal tabs. Should be on tab one.
-  SwitchToNormalMode();
+
+  NSError* switchError = SwitchToNormalMode();
+  GREYAssertNil(switchError, switchError.localizedDescription);
+
   [ChromeEarlGrey waitForWebViewContainingText:kURL1FirstWord];
 
   histogramTester.ExpectTotalCount(kSelectedTabHistogramName, 2, failureBlock);
@@ -216,11 +221,14 @@ void CloseTabAtIndexAndSync(NSUInteger i) {
   // Evict the tab. Create a dummy tab so that switching back to normal mode
   // does not trigger a reload immediately.
   [ChromeEarlGrey openNewTab];
-  OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  NSError* openError = OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  GREYAssertNil(openError, openError.localizedDescription);
   [ChromeEarlGrey waitForIncognitoTabCount:1];
 
   // Switch back to the normal tabs. Should be on tab one.
-  SwitchToNormalMode();
+  NSError* switchError = SwitchToNormalMode();
+  GREYAssertNil(switchError, switchError.localizedDescription);
+
   chrome_test_util::SelectTabAtIndexInCurrentMode(0);
   [ChromeEarlGrey waitForWebViewContainingText:kURL1FirstWord];
 
@@ -254,12 +262,17 @@ void CloseTabAtIndexAndSync(NSUInteger i) {
                  @"Fail to state tabs as cold start tabs");
 
   // Open two incognito tabs with urls, clearing normal tabs from memory.
-  OpenNewIncognitoTabUsingUIAndEvictMainTabs();
-  OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  NSError* firstTabError = OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  GREYAssertNil(firstTabError, firstTabError.localizedDescription);
+  NSError* secondTabError = OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  GREYAssertNil(secondTabError, secondTabError.localizedDescription);
+
   [ChromeEarlGrey waitForIncognitoTabCount:2];
 
   // Switch back to the normal tabs.
-  SwitchToNormalMode();
+  NSError* switchError = SwitchToNormalMode();
+  GREYAssertNil(switchError, switchError.localizedDescription);
+
   [ChromeEarlGrey waitForWebViewContainingText:kURL2FirstWord];
 
   // Select the other one so it also reloads.
@@ -308,13 +321,16 @@ void CloseTabAtIndexAndSync(NSUInteger i) {
                  @"Fail to simulate tab backgrounding.");
 
   // Open incognito and clear normal tabs from memory.
-  OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  NSError* openError = OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  GREYAssertNil(openError, openError.localizedDescription);
   GREYAssertTrue(chrome_test_util::IsIncognitoMode(),
                  @"Failed to switch to incognito mode");
   histogramTester.ExpectTotalCount(kEvictedTabReloadTime, 0, failureBlock);
 
   // Switch back to the normal tabs.
-  SwitchToNormalMode();
+  NSError* switchError = SwitchToNormalMode();
+  GREYAssertNil(switchError, switchError.localizedDescription);
+
   [ChromeEarlGrey waitForWebViewContainingText:kURL2FirstWord];
 
   const GURL url1 = web::test::HttpServer::MakeUrl(kTestUrl1);
@@ -345,8 +361,12 @@ void CloseTabAtIndexAndSync(NSUInteger i) {
   [ChromeEarlGrey closeAllTabsInCurrentMode];
   GURL URL = web::test::HttpServer::MakeUrl(kTestUrl1);
   NewMainTabWithURL(URL, kURL1FirstWord);
-  OpenNewIncognitoTabUsingUIAndEvictMainTabs();
-  SwitchToNormalMode();
+  NSError* openError = OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  GREYAssertNil(openError, openError.localizedDescription);
+
+  NSError* switchError = SwitchToNormalMode();
+  GREYAssertNil(switchError, switchError.localizedDescription);
+
   [ChromeEarlGrey waitForWebViewContainingText:kURL1FirstWord];
   [ChromeEarlGrey waitForMainTabCount:1];
 
@@ -378,12 +398,18 @@ void CloseTabAtIndexAndSync(NSUInteger i) {
   [ChromeEarlGrey openNewTab];
   [ChromeEarlGrey openNewTab];
   chrome_test_util::LoadUrl(slowURL);
-  OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  NSError* openError = OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  GREYAssertNil(openError, openError.localizedDescription);
 
   web::test::SetUpHttpServer(std::make_unique<web::DelayedResponseProvider>(
       std::make_unique<HtmlResponseProvider>(responses), kSlowURLDelay));
 
-  SwitchToNormalMode();
+  NSError* switchError = SwitchToNormalMode();
+  // TODO(crbug.com/951600): We avoid asserting directly unless the test fails,
+  // due to timing issues.
+  if (switchError != nil) {
+    GREYAssert(false, switchError.localizedDescription);
+  }
 
   // Turn off synchronization of GREYAssert to test the pending states.
   [[GREYConfiguration sharedInstance]
@@ -425,11 +451,17 @@ void CloseTabAtIndexAndSync(NSUInteger i) {
 
   NewMainTabWithURL(slowURL, "Slow");
 
-  OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  NSError* openError = OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  GREYAssertNil(openError, openError.localizedDescription);
   web::test::SetUpHttpServer(std::make_unique<web::DelayedResponseProvider>(
       std::make_unique<HtmlResponseProvider>(responses), kSlowURLDelay));
 
-  SwitchToNormalMode();
+  NSError* switchError = SwitchToNormalMode();
+  // TODO(crbug.com/951600): We avoid asserting directly unless the test fails,
+  // due to timing issues.
+  if (switchError != nil) {
+    GREYAssert(false, switchError.localizedDescription);
+  }
 
   // Letting page load start.
   base::test::ios::SpinRunLoopWithMinDelay(base::TimeDelta::FromSecondsD(0.5));
@@ -470,9 +502,12 @@ void CloseTabAtIndexAndSync(NSUInteger i) {
   };
 
   NewMainTabWithURL(slowURL, responses[slowURL]);
-  OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  NSError* openError = OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  GREYAssertNil(openError, openError.localizedDescription);
+
+  NSError* switchError = SwitchToNormalMode();
+  GREYAssertNil(switchError, switchError.localizedDescription);
 
-  SwitchToNormalMode();
   [ChromeEarlGreyUI openSettingsMenu];
   [ChromeEarlGreyUI tapSettingsMenuButton:SettingsMenuPrivacyButton()];
   [[EarlGrey selectElementWithMatcher:SettingsDoneButton()]
@@ -500,11 +535,17 @@ void CloseTabAtIndexAndSync(NSUInteger i) {
   [ChromeEarlGrey openNewTab];
   chrome_test_util::LoadUrl(slowURL);
 
-  OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  NSError* openError = OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  GREYAssertNil(openError, openError.localizedDescription);
 
   web::test::SetUpHttpServer(std::make_unique<web::DelayedResponseProvider>(
       std::make_unique<HtmlResponseProvider>(responses), kSlowURLDelay));
-  SwitchToNormalMode();
+  NSError* switchError = SwitchToNormalMode();
+  // TODO(crbug.com/951600): We avoid asserting directly unless the test fails,
+  // due to timing issues.
+  if (switchError != nil) {
+    GREYAssert(false, switchError.localizedDescription);
+  }
 
   // Letting page load start.
   base::test::ios::SpinRunLoopWithMinDelay(base::TimeDelta::FromSecondsD(0.5));
@@ -585,8 +626,12 @@ void CloseTabAtIndexAndSync(NSUInteger i) {
 
   NSUInteger tabIndex = chrome_test_util::GetMainTabCount() - 1;
   [ChromeEarlGrey openNewTab];
-  OpenNewIncognitoTabUsingUIAndEvictMainTabs();
-  SwitchToNormalMode();
+  NSError* openError = OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  GREYAssertNil(openError, openError.localizedDescription);
+
+  NSError* switchError = SwitchToNormalMode();
+  GREYAssertNil(switchError, switchError.localizedDescription);
+
   chrome_test_util::SelectTabAtIndexInCurrentMode(tabIndex);
   [ChromeEarlGrey waitForWebViewContainingText:"arrived"];
 
@@ -632,8 +677,12 @@ void CloseTabAtIndexAndSync(NSUInteger i) {
   [ChromeEarlGrey waitForWebViewContainingText:"Whee"];
   NSUInteger tabIndex = chrome_test_util::GetMainTabCount() - 1;
   [ChromeEarlGrey openNewTab];
-  OpenNewIncognitoTabUsingUIAndEvictMainTabs();
-  SwitchToNormalMode();
+  NSError* openError = OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+  GREYAssertNil(openError, openError.localizedDescription);
+
+  NSError* switchError = SwitchToNormalMode();
+  GREYAssertNil(switchError, switchError.localizedDescription);
+
   chrome_test_util::SelectTabAtIndexInCurrentMode(tabIndex);
   [ChromeEarlGrey waitForWebViewContainingText:"Whee"];
 
@@ -665,11 +714,11 @@ void CloseTabAtIndexAndSync(NSUInteger i) {
       web::test::HttpServer::MakeUrl("http://destination");
   // Make the link that cover the whole page so that long pressing the web view
   // will trigger the link context menu.
-  responses[initialURL] = base::StringPrintf(
-      "<body style='width:auto; height:auto;'><a href='%s' "
-      "id='link'><div style='width:100%%; "
-      "height:100%%;'>link</div></a></body>",
-      destinationURL.spec().c_str());
+  responses[initialURL] =
+      base::StringPrintf("<body style='width:auto; height:auto;'><a href='%s' "
+                         "id='link'><div style='width:100%%; "
+                         "height:100%%;'>link</div></a></body>",
+                         destinationURL.spec().c_str());
   responses[destinationURL] = "Whee!";
   web::test::SetUpHttpServer(std::make_unique<HtmlResponseProvider>(responses));
   chrome_test_util::HistogramTester histogramTester;

ios/chrome/browser/metrics/tab_usage_recorder_test_util.h

@@ -5,14 +5,16 @@
 #ifndef IOS_CHROME_BROWSER_METRICS_TAB_USAGE_RECORDER_TEST_UTIL_H_
 #define IOS_CHROME_BROWSER_METRICS_TAB_USAGE_RECORDER_TEST_UTIL_H_
 
+@class NSError;
+
 namespace tab_usage_recorder_test_util {
 
 // Opens a new incognito tab using the UI and evicts any main tab model tabs.
-void OpenNewIncognitoTabUsingUIAndEvictMainTabs();
+NSError* OpenNewIncognitoTabUsingUIAndEvictMainTabs();
 
 // Switches to normal mode using the tab switcher and selects the
 // previously-selected normal tab. Assumes current mode is Incognito.
-void SwitchToNormalMode();
+NSError* SwitchToNormalMode();
 
 }  // namespace tab_usage_recorder_test_util
 

ios/chrome/browser/metrics/tab_usage_recorder_test_util.mm

@@ -21,6 +21,7 @@
 #import "ios/chrome/test/app/tab_test_util.h"
 #import "ios/chrome/test/earl_grey/chrome_earl_grey.h"
 #import "ios/chrome/test/earl_grey/chrome_earl_grey_ui.h"
+#import "ios/chrome/test/earl_grey/chrome_error_util.h"
 #import "ios/chrome/test/earl_grey/chrome_matchers.h"
 #include "ui/base/l10n/l10n_util_mac.h"
 
@@ -35,7 +36,7 @@ const NSTimeInterval kWaitElementTimeout = 3;
 
 // Shows the tab switcher by tapping the switcher button.  Works on both phone
 // and tablet.
-void ShowTabSwitcher() {
+bool ShowTabSwitcher() {
   id<GREYMatcher> matcher = chrome_test_util::TabGridOpenButton();
   // Perform a tap with a timeout. Occasionally EG doesn't sync up properly to
   // the animations of tab switcher, so it is necessary to poll here.
@@ -50,15 +51,14 @@ void ShowTabSwitcher() {
                                  }];
 
   // Wait until 2 seconds for the tap.
-  BOOL hasClicked = [tapTabSwitcher waitWithTimeout:2];
-  GREYAssertTrue(hasClicked, @"Tab switcher could not be tapped.");
+  return [tapTabSwitcher waitWithTimeout:2];
 }
 
 }  // namespace
 
 namespace tab_usage_recorder_test_util {
 
-void OpenNewIncognitoTabUsingUIAndEvictMainTabs() {
+NSError* OpenNewIncognitoTabUsingUIAndEvictMainTabs() {
   int nb_incognito_tab = chrome_test_util::GetIncognitoTabCount();
   [ChromeEarlGreyUI openToolsMenu];
   id<GREYMatcher> new_incognito_tab_button_matcher =
@@ -69,18 +69,29 @@ void OpenNewIncognitoTabUsingUIAndEvictMainTabs() {
   ConditionBlock condition = ^bool {
     return chrome_test_util::IsIncognitoMode();
   };
-  GREYAssert(base::test::ios::WaitUntilConditionOrTimeout(kWaitElementTimeout,
-                                                          condition),
-             @"Waiting switch to incognito mode.");
+
+  bool success = base::test::ios::WaitUntilConditionOrTimeout(
+      kWaitElementTimeout, condition);
+  if (!success) {
+    return chrome_test_util::NSErrorWithLocalizedDescription(
+        @"Waiting switch to incognito mode.");
+  }
+
   chrome_test_util::EvictOtherTabModelTabs();
+  return nil;
 }
 
-void SwitchToNormalMode() {
-  GREYAssertTrue(chrome_test_util::IsIncognitoMode(),
-                 @"Switching to normal mode is only allowed from Incognito.");
+NSError* SwitchToNormalMode() {
+  if (!chrome_test_util::IsIncognitoMode()) {
+    return chrome_test_util::NSErrorWithLocalizedDescription(
+        @"Switching to normal mode is only allowed from Incognito.");
+  }
 
   // Enter the tab grid to switch modes.
-  ShowTabSwitcher();
+  if (!ShowTabSwitcher()) {
+    return chrome_test_util::NSErrorWithLocalizedDescription(
+        @"Tab switcher could not be tapped.");
+  }
 
   // Switch modes and exit the tab grid.
   TabModel* model = chrome_test_util::GetMainController()
@@ -99,13 +110,17 @@ void SwitchToNormalMode() {
   ConditionBlock condition = ^bool {
     return !chrome_test_util::IsIncognitoMode();
   };
-  GREYAssert(base::test::ios::WaitUntilConditionOrTimeout(kWaitElementTimeout,
-                                                          condition),
-             @"Waiting switch to normal mode.");
+
+  if (!base::test::ios::WaitUntilConditionOrTimeout(kWaitElementTimeout,
+                                                    condition)) {
+    return chrome_test_util::NSErrorWithLocalizedDescription(
+        @"Waiting switch to normal mode.");
+  }
 
   [[GREYConfiguration sharedInstance]
           setValue:@(YES)
       forConfigKey:kGREYConfigKeySynchronizationEnabled];
+  return nil;
 }
 
 }  // namespace tab_usage_recorder_test_util

ios/chrome/test/earl_grey/BUILD.gn

@@ -227,6 +227,8 @@ source_set("test_support") {
     "chrome_earl_grey.mm",
     "chrome_earl_grey_ui.h",
     "chrome_earl_grey_ui.mm",
+    "chrome_error_util.h",
+    "chrome_error_util.mm",
     "chrome_matchers.h",
     "chrome_matchers.mm",
     "chrome_matchers_shorthand.h",

ios/chrome/test/earl_grey/chrome_error_util.h

+// Copyright 2019 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.
+
+#ifndef IOS_CHROME_TEST_EARL_GREY_CHROME_ERROR_UTIL_H_
+#define IOS_CHROME_TEST_EARL_GREY_CHROME_ERROR_UTIL_H_
+
+@class NSError;
+@class NSString;
+
+namespace chrome_test_util {
+
+// Returns a NSError with generic domain and error code, and the provided string
+// as localizedDescription.
+NSError* NSErrorWithLocalizedDescription(NSString* error_description);
+
+}  // namespace chrome_test_util
+
+#endif  // IOS_CHROME_TEST_EARL_GREY_CHROME_ERROR_UTIL_H_

ios/chrome/test/earl_grey/chrome_error_util.mm

+// Copyright 2019 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 "ios/chrome/test/earl_grey/chrome_error_util.h"
+
+#import <Foundation/Foundation.h>
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace chrome_test_util {
+
+NSError* NSErrorWithLocalizedDescription(NSString* error_description) {
+  NSDictionary* userInfo = @{
+    NSLocalizedDescriptionKey : error_description,
+  };
+
+  return [[NSError alloc] initWithDomain:@"com.google.chrome.errorDomain"
+                                    code:0
+                                userInfo:userInfo];
+}
+
+}  // namespace chrome_test_util