Hack With Me: Unit and Behavioral Tests PDXWP APRIL 27, 2013 

Who am I? @MAXCUTLER HTTP://WWW.MAXCUTLER.COM 

Why write tests? Verify functionality Validate technical design Protect against regressions Refactor with confidence Documentation 

Unit testing 

What is a unit? 

But, what about the rest? Integration testing Acceptance testing Behavioral testing 

Code coverage How much of the non-test code is exercised by test cases 100% coverage? Depends on project priorities Pragmatic, not dogmatic WordPress core has plenty of room for improvement ◦ Patches! 

Code coverage 

Frameworks PHP: PHPUnit, SimpleTest, Behat JavaScript: QUnit, Jasmine, Mocha And many more, for almost every programming language For UI automation: Selenium, Watir For headless browser testing: Phantom.js 

PHPUnit HTTP://PHPUNIT.DE 

Anatomy of a test Class extending PHPUnit_Framework_TestCase At least one test method Optional setUp and tearDown ◦ Shared among all test methods in the class setUp testMethod •Assertion 1 •Assertion 2 •… tearDown 

Anatomy of a test 

Assertions assertArrayHasKey() assertClassHasAttribute() assertClassHasStaticAttribute() assertContains() assertContainsOnly() assertContainsOnlyInstancesOf() assertCount() assertEmpty() assertEqualXMLStructure() assertEquals() assertFalse() assertFileEquals() assertFileExists() assertGreaterThan() assertGreaterThanOrEqual() assertInstanceOf() assertInternalType() assertJsonFileEqualsJsonFile() assertJsonStringEqualsJsonFile() assertJsonStringEqualsJsonString() assertLessThan() assertLessThanOrEqual() assertNull() assertObjectHasAttribute() assertRegExp() assertStringMatchesFormat() assertStringMatchesFormatFile() assertSame() assertSelectCount() assertSelectEquals() assertSelectRegExp() assertStringEndsWith() assertStringEqualsFile() assertStringStartsWith() assertTag() assertThat() assertTrue() assertXmlFileEqualsXmlFile() assertXmlStringEqualsXmlFile() assertXmlStringEqualsXmlString() expectOutputString() setExpectedException() 

Data providers 

Stubs & Mocks When testing a unit, replace any dependencies with fakes that are fully under control of the test Stubs ◦ Replaces all methods with stubs ◦ You configure return values of any methods Mocks ◦ Verify the behavior of interactions between unit and other objects ◦ Beware of coupling test to implementation 

Running tests Usage: phpunit [switches] UnitTest [UnitTest.php] phpunit [switches] --filter Filter which tests to run. --group ... Only runs tests from the specified group(s). --exclude-group ... Exclude tests from the specified group(s). --list-groups List available test groups. --repeat Runs the test(s) repeatedly. --colors Use colors in output. --stderr Write to STDERR instead of STDOUT. --stop-on-error Stop execution upon first error. --stop-on-failure Stop execution upon first error or failure. --stop-on-skipped Stop execution upon first skipped test. --stop-on-incomplete Stop execution upon first incomplete test. --strict Run tests in strict mode. -v|--verbose Output more verbose information. --debug Display debbuging information during test execution. --process-isolation Run each test in a separate PHP process. --bootstrap A "bootstrap" PHP file that is run before the tests. -c|--configuration Read configuration from XML file. --no-configuration Ignore default configuration file (phpunit.xml). --include-path Prepend PHP's include_path with given path(s). -d key[=value] Sets a php.ini value. -h|--help Prints this usage information. --version Prints the version and exits. --debug Output debugging information. 

Running tests Command-line IDE Integrations ◦ PHPStorm ◦ Eclipse ◦ Netbeans ◦ Sublime Text 2 ◦ … Continuous Integration Servers ◦ Jenkins ◦ Travis ◦ … 

WordPress testing 

WordPress Core Unit Tests http://make.wordpress.org/core/handbook/automated-testing/ On WP Core trac ◦ “Unit Tests” component ◦ “needs-unit-tests” keyword Jenkins CI ◦ http://jenkins.kpayne.co:8080 ◦ Automatically runs unit tests after commits ◦ Provides pass/fail history, code coverage, automatic code documentation, and more 

Organization Base classes ◦ WP_UnitTestCase ◦ WP_Ajax_UnitTestCase ◦ WP_XMLRPC_UnitTestCase WP_UnitTest_Factory ◦ Use to create data for tests ◦ WP_UnitTest_Factory_For_* ◦ Post, Attachment, User, Term, Blog, Comment ◦ create, create_and_get, create_many Annotations: ◦ @group ◦ @ticket Mocks: ◦ MockAction ◦ MockPHPMailer ◦ WP_Image_Editor_Mock 

WP_UnitTestCase setUp ◦ Open database connection ◦ Create WP_UnitTest_Factory ◦ Clean up global scope ◦ Clear $_GET, $_POST, flush object cache ◦ Beware global scope – avoid constants (see multisite, ajax) ◦ Start a DB transaction tearDown ◦ Rollback the DB transaction Correlates @ticket annotation to Trac tickets and skips tests for known issues ◦ Works for Core, Unit Tests, and Plugin tickets 

How can you help? Fix failing test cases Improve code coverage Write patches for core tickets that are causing skipped/failed tests ◦ needs-unit-tests tickets ◦ Tests for any core bugs Does your plugin use a core API or action? Write a test for it so that core devs do not unintentionally break your use-case. Write tests for your plugins!