GTXiLib 是 Google 开源的 iOS 专用自动化测试框架

GTXiLib 是 Google 开源的 iOS 专用自动化测试框架

What is GTXiLib?

GTXiLib, Google Toolbox for Accessibility for the iOS platform or simply GTX-eye is a framework for iOS accessibility testing. GTXiLib has XCTest integration and can be used with any XCTest-based frameworks such as EarlGrey. GTXiLib enhances the value of your tests by installing "accessibility checks" on them; your existing test cases can double as accessibility tests with no other code change on your part. GTXiLib is able to accomplish this by hooking into the test tear-down process and invoking the registered accessibility checks (such as check for presence of accessibility label) on all elements on the screen.

Getting Started

To install GTXiLib on all the tests of a specific test class add the following snippet of code to it.

// Include the GTXiLib umbrella header.// Note that that is +setUp not -setUp+ (void)setUp { [super setUp]; // ... your other setup code (if any) comes here. // Create an array of checks to be installed. NSArray *checksToBeInstalled = @[ [GTXChecksCollection checkForAXLabelPresent] ]; // Install GTX on all tests in *this* test class. [GTXiLib installOnTestSuite:[GTXTestSuite suiteWithAllTestsInClass:self] checks:checksToBeInstalled elementBlacklists:@[]];}

Once installed, GTX will run all registered accessibility checks before test case tearDown and fail the test if any accessibility checks fail. With the above snippet of code your tests will now begin to catch issues where you have added UI elements to your app but forgot to set accessibility labels on them.

In the above snippet we have only installed checkForAXLabelPresent, but you can also install multiple checks from GTXChecksCollection or include your own custom checks as well:

// Inside +setUp ...// Create a new check (for example that ensures that all AX label is not an image name)id myNewCheck = [GTXCheckBlock GTXCheckWithName:@"AXlabel is not image name" block:^BOOL(id element, GTXErrorRefType errorPtr) { // Ensure accessibilityLabel does not end with .png return ![[element accessibilityLabel] hasSuffix:@".png"]; }];// Create an array of checks to be installed.NSArray *checksToBeInstalled = @[ [GTXChecksCollection checkForAXLabelPresent], [GTXChecksCollection checkForAXTraitDontConflict], myNewCheck,];// Install GTX on all tests in *this* test class.[GTXiLib installOnTestSuite:[GTXTestSuite suiteWithAllTestsInClass:self] checks:checksToBeInstalled elementBlacklists:@[]];

Note that GTX is being added to +setUp method, not the instance method -setUp since GTX must only be installed once (for a given test run).

To add GTXiLib to your project use the xcodeproj file in this project or cocoapods.

Incremental Accessibility

GTXiLib APIs support a practical solution for improving accessibility of large projects which may not have included accessibility from the get-go -- incremental accessibility. Adding GTXiLib to a project that is already halfway through development may lead to several test failures and fixing them at once can be time consuming and tedious. To solve this problem incrementally:

Use the above snippet to add GTXiLib to all test cases but fix errors in a small subset of them. Blacklist elements that you don't control using GTXiLib's blacklist APIs. Then use GTXTestSuite's suiteWithClass:andTests: method to create a test suite with only the tests cases that have been fixed and add GTXiLib only to that suite.

Once the code is checked into your repo GTXiLib will catch any new failures in those tests. From this point:

Every new test being added must be added to the suite.Based on team priorities keep moving existing tests into the suite until all methods are in the suite.

If at any point all the tests of a test class are in the suite use suiteWithAllTestsInClass: method instead of listing all the methods, this also ensures that new methods added to the class are automatically under accessibility checking.

If GTXiLib is installed on every test in your project, use suiteWithAllTestsFromAllClassesInheritedFromClass: to automatically add accessibility checking to any test case added.

Authoring your own checks

GTXiLib has APIs that allow for creation of your own accessibility checks (in fact it does not have to be related to accessibility, for example i18n layout checks or even memory usage checks). To create new checks use GTXiLib's checkWithName:block: API and provide a unique name and block that evaluates the check and returns YES/NO for success/failure. Add the newly created check to the array of checks being passed on to GTXiLib via the install API call.

Dealing with GTXiLib Failures

When GTXiLib fails it has most likely found an accessibility bug and you must fix it. But due to various team priorities it may not be possible to do so right away in which case you have the following options at your disposal:

Temporarily blacklist the test case by using suiteWithAllTestsInClass:exceptTests:.Temporarily blacklist the offending element using element blacklist APIs.

But if you believe GTXiLib has caught a bug that is not an accessibility issue please let us know by filing a bug or better fix it for everyone.

Integrating GTXiLib into custom test frameworks

If you are test framework author you can use GTXToolKit class to integrate accessibility checking into your test framework. GTXiLib's own XCTest integration is also built using the APIs provided by GTXToolKit. Using GTXToolKit for performing accessibility checks on a given element involves:

Creating a GTXToolKit object.Associating a set of checks with it.Use it on the element to be checked.

GTXToolKit *toolkit = [[GTXToolKit alloc] init];// Register one or more built in checks:[toolkit registerCheck:[GTXChecksCollection checkForAXLabelPresent]];[toolkit registerCheck:[GTXChecksCollection checkForAXLabelNotPunctuated]];// and/or add a couple of your own:id fooCustomCheck = [GTXCheckBlock GTXCheckWithName:@"AXlabel is not image name" block:^BOOL(id element, GTXErrorRefType errorPtr) { // Check logic comes here... return YES; }];[toolkit registerCheck:fooCustomCheck];// Use the toolkit on an element.NSError *error;BOOL success = [toolkit checkElement:someElement error:&error];if (!success) { NSLog(@"Element FAILED accessibility checks! Error: %@", [error localizedDescription]);} else { NSLog(@"Element PASSED accessibility checks!");}

GTXToolKit objects can also be applied on a tree of elements by just providing the root element.

// Use the toolkit on a tree of elements by providing a root element.NSError *error;BOOL success = [toolkit checkAllElementsFromRootElements:@[rootElement] error:&error];if (!success) { NSLog(@"One or more elements FAILED accessibility checks! Error: %@", error);} else { NSLog(@"All elements PASSED accessibility checks!");}

When using checkAllElementsFromRootElements:, you may want to ignore some elements from checks for various reasons, you can do that using GTXToolKit's ignore APIs.

- (void)ignoreElementsOfClassNamed:(NSString *)className;- (void)ignoreElementsOfClassNamed:(NSString *)className forCheckNamed:(NSString *)skipCheckName;

Also, note that checkAllElementsFromRootElements: requires an array of root elements, not a single element. The following snippet shows how to run the checks on all elements on the screen:

// Run the checks on all elements on the screen.[toolkit checkAllElementsFromRootElements:@[[UIApplication sharedApplication].keyWindow] error:&error];

For full latest reference please refer GTXToolKit.h file.

Analytics

To prioritize and improve GTXiLib, the framework collects usage data and uploads it to Google Analytics. More specifically, the framework collects the MD5 hash of the test app's Bundle ID and pass/fail status of GTXiLib checks. This information allows us to measure the volume of usage. For more detailed information about our analytics collection, please peruse the GTXAnalytics.m file which contains the implementation details. If they wish, users can choose to opt out by disabling the Analytics by adding the following code snippet in test’s +(void) setUp method:

// Disable GTXiLib analytics.[GTXAnalytics setEnabled:NO];

Discuss

Please join us on the ios-accessibility Google group to discuss all things accessibility and also to keep a tab on all updates to GTXiLib.

Contributors

Please make sure you’ve followed the guidelines in CONTRIBUTING.md before making any contributions.

Note: This is not an official Google product.

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