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06-ReusingTestCode - Codeception - Documentation |
Codeception uses modularity to create a comfortable testing environment for every test suite you write. Modules allow you to choose the actions and assertions that can be performed in tests.
All actions and assertions that can be performed by the Actor object in a class are defined in modules. It might look like Codeception limits you in testing, but that's not true. You can extend the testing suite with your own actions and assertions, by writing them into a custom module, called Helper. We will get back to this later in this chapter, but now let's look at the following test:
{% highlight php %}
amOnPage('/'); $I->see('Hello'); $I->seeInDatabase('users', ['id' => 1]); $I->seeFileFound('running.lock'); ?>{% endhighlight %}
It can operate with different entities: the web page can be loaded with the PhpBrowser module, the database assertion uses the Db module, and file state can be checked with the Filesystem module.
Modules are attached to Actor classes in the suite config.
For example, in tests/acceptance.suite.yml we should see:
{% highlight yaml %}
class_name: AcceptanceTester modules: enabled: - PhpBrowser: url: http://localhost - Db - Filesystem
{% endhighlight %}
The AcceptanceTester class has its methods defined in modules. But let's see what's inside AcceptanceTester class, which is located inside tests/_support directory:
{% highlight php %}
{% endhighlight %}
The most important part is _generated\AcceptanceTesterActions trait, which is used as a proxy for enabled modules. It knows which module executes which action and passes parameters into it. This trait was created by running codecept build and is regenerated each time module or configuration changes.
It is recommended to put widely used actions inside an Actor class. A good example of such case may be login action which probably be actively involved in acceptance or functional testing.
{% highlight php %}
amOnPage('/login'); $I->submitForm('#loginForm', [ 'login' => $name, 'password' => $password ]); $I->see($name, '.navbar'); } } ?>{% endhighlight %}
Now you can use login method inside your tests:
{% highlight php %}
login('miles', '123456'); ?>{% endhighlight %}
However, implementing all actions for a reuse in one actor class may lead to breaking the Single Responsibility Principle.
If login method defined in Actor class may be used in 90% of your tests,
StepObjects are great if you need some common functionality for a group of tests. Let's say you are going to test an admin area of a site. Probably, you won't need the same actions from admin area while testing the frontend, so it's a good idea to move those admin-specific into their own class. We will call such class a StepObject.
Lets create an Admin StepObject with generator, by specifying test suite, and passing method expected names on prompt.
{% highlight bash %}
$ php codecept.phar generate:stepobject acceptance Admin
{% endhighlight %}
You will be asked to enter action names, but it's optional. Enter one at a time, and press Enter. After specifying all needed actions, leave empty line to go on to StepObject creation.
{% highlight bash %}
$ php codecept.phar generate:stepobject acceptance Admin Add action to StepObject class (ENTER to exit): loginAsAdmin Add action to StepObject class (ENTER to exit): StepObject was created in /tests/acceptance/_support/Step/Acceptance/Admin.php
{% endhighlight %}
It will generate class in /tests/_support/Step/Acceptance/Admin.php similar to this:
{% highlight php %}
{% endhighlight %}
As you see, this class is very simple. It extends AcceptanceTester class, thus, all methods and properties of AcceptanceTester are available for usage in it.
loginAsAdmin method may be implemented like this:
{% highlight php %}
amOnPage('/admin'); $I->fillField('username', 'admin'); $I->fillField('password', '123456'); $I->click('Login'); } } ?>{% endhighlight %}
In tests you can use a StepObject by instantiating Step\Acceptance\Admin instead of AcceptanceTester.
{% highlight php %}
loginAsAdmin(); ?>{% endhighlight %}
Same as above, StepObject can be instantiated automatically by Dependency Injection Container, when used inside Cest format:
{% highlight php %}
loginAsAdmin(); $I->amOnPage('/admin/profile'); $I->see('Admin Profile', 'h1'); } } ?>{% endhighlight %}
If you have complex interaction scenario you may use several step objects in one test. If you feel like adding too many actions into your Actor class (which is AcceptanceTester in this case) consider to move some of them into separate StepObjects.
For acceptance and functional testing we will need not only to have common actions to be reused across different tests, we should have buttons, links, and form fields to be reused as well. For those cases we need to implement PageObject pattern, which is widely used by test automation engineers. The PageObject pattern represents a web page as a class and the DOM elements on that page as its properties, and some basic interactions as its methods. PageObjects are very important when you are developing a flexible architecture of your tests. Please do not hardcode complex CSS or XPath locators in your tests but rather move them into PageObject classes.
Codeception can generate a PageObject class for you with command:
{% highlight bash %}
$ php codecept.phar generate:pageobject Login
{% endhighlight %}
This will create a Login class in tests/_support/Page. The basic PageObject is nothing more than an empty class with a few stubs.
It is expected you will get it populated with UI locators of a page it represents and then those locators will be used on a page.
Locators are represented with public static properties:
{% highlight php %}
{% endhighlight %}
And this is how this page object can be used in a test:
{% highlight php %}
wantTo('login to site'); $I->amOnPage(LoginPage::$URL); $I->fillField(LoginPage::$usernameField, 'bill evans'); $I->fillField(LoginPage::$passwordField, 'debby'); $I->click(LoginPage::$loginButton); $I->see('Welcome, bill'); ?>{% endhighlight %} As you see, you can freely change markup of your login page, and all the tests interacting with this page will have their locators updated according to properties of LoginPage class.
But let's move further. A PageObject concept also defines that methods for the page interaction should also be stored in a PageObject class. It now stores a passed instance of an Actor class. An AcceptanceTester can be accessed via AcceptanceTester property of that class. Let's define a login method in this class.
{% highlight php %}
tester = $I; } public function login($name, $password) { $I = $this->tester; $I->amOnPage(self::$URL); $I->fillField(self::$usernameField, $name); $I->fillField(self::$passwordField, $password); $I->click(self::$loginButton); return $this; } } ?>{% endhighlight %}
And here is an example of how this PageObject can be used in a test.
{% highlight php %}
login('bill evans', 'debby'); $I->amOnPage('/profile'); $I->see('Bill Evans Profile', 'h1'); ?>{% endhighlight %}
If you write your scenario-driven tests in Cest format (which is the recommended approach), you can bypass manual creation of a PageObject and delegate this task to Codeception. If you specify which object you need for a test, Codeception will try to create it using the dependency injection container. In the case of a PageObject you should declare a class as a parameter for a test method:
{% highlight php %}
login('bill evans', 'debby'); $I->amOnPage('/profile'); $I->see('Bill Evans Profile', 'h1'); } } ?>{% endhighlight %}
The dependency injection container can construct any object that require any known class type. For instance, Page\Login required AcceptanceTester, and so it was injected into Page\Login constructor, and PageObject was created and passed into method arguments. You should specify explicitly the types of required objects for Codeception to know what objects should be created for a test. Dependency Injection will be described in the next chapter.
In the examples above we only grouped actions into one. What happens when we need to create a custom action?
In this case it's a good idea to define missing actions or assertion commands in custom modules, which are called Helpers. They can be found in the tests/_support/Helper directory.
{% highlight php %}
{% endhighlight %}
As for actions, everything is quite simple. Every action you define is a public function. Write any public method, run the build command, and you will see the new function added into the FunctionalTester class.
Assertions can be a bit tricky. First of all, it's recommended to prefix all your assert actions with see or dontSee.
Name your assertions like this:
{% highlight php %}
seePageReloaded(); $I->seeClassIsLoaded($classname); $I->dontSeeUserExist($user); ?>{% endhighlight %} And then use them in your tests:
{% highlight php %}
seePageReloaded(); $I->seeClassIsLoaded('FunctionalTester'); $I->dontSeeUserExist($user); ?>{% endhighlight %}
You can define asserts by using assertXXX methods in modules. Not all PHPUnit assert methods are included in modules, but you can use PHPUnit static methods from the PHPUnit_Framework_Assert class to leverage all of them.
{% highlight php %}
assertTrue(class_exists($class)); // or \PHPUnit_Framework_Assert::assertTrue(class_exists($class)); } ?>{% endhighlight %}
In your helpers you can use these assertions:
{% highlight php %}
assertTrue(isset($thing), "this thing is set"); $this->assertFalse(empty($any), "this thing is not empty"); $this->assertNotNull($thing, "this thing is not null"); $this->assertContains("world", $thing, "this thing contains 'world'"); $this->assertNotContains("bye", $thing, "this thing doesn`t contain 'bye'"); $this->assertEquals("hello world", $thing, "this thing is 'Hello world'!"); // ... } ?>{% endhighlight %}
What happens if you have two modules that contain the same named actions? Codeception allows you to override actions by changing the module order. The action from the second module will be loaded and the action from the first one will be ignored. The order of the modules can be defined in the suite config.
However, some of modules may conflict with each other. In order to avoid confusion which module is used in the first place, Framework modules, PhpBrowser, and WebDriver can't be used together. The _conflicts method of a module is used to specify which class or interface it conflicts with. Codeception will throw an exception if there will be a module enabled which matches the provided criteria.
It's possible that you will need to access internal data or functions from other modules. For example, for your module you might need to access responses or internal actions of modules.
Modules can interact with each other through the getModule method. Please note that this method will throw an exception if the required module was not loaded.
Let's imagine that we are writing a module that reconnects to a database. It's supposed to use the dbh connection value from the Db module.
{% highlight php %}
getModule('Db')->dbh; $dbh->close(); $dbh->open(); } ?>{% endhighlight %}
By using the getModule function, you get access to all of the public methods and properties of the requested module. The dbh property was defined as public specifically to be available to other modules.
Modules may also contain methods that are exposed for use in helper classes. Those methods start with _ prefix and are not available in Actor classes, so can be accessed only from modules and extensions.
You should use them to write your own actions using module internals.
{% highlight php %}
getModule('WebDriver')->_findElements('#result'); $this->assertNotEmpty($elements); $table = reset($elements); $this->assertEquals('table', $table->getTagName()); $results = $table->findElements('tr'); // asserting that table contains exactly $num rows $this->assertEquals($num, count($results)); } ?>{% endhighlight %}
In this example we use API of facebook/php-webdriver library, a Selenium WebDriver client a module is build on.
You can also access webDriver property of a module to get access to Facebook\WebDriver\RemoteWebDriver instance for direct Selenium interaction.
Each module can handle events from the running test. A module can be executed before the test starts, or after the test is finished. This can be useful for bootstrap/cleanup actions.
You can also define special behavior for when the test fails. This may help you in debugging the issue.
For example, the PhpBrowser module saves the current webpage to the tests/_output directory when a test fails.
All hooks are defined in \Codeception\Module and are listed here. You are free to redefine them in your module.
{% highlight php %}
{% endhighlight %}
Please note that methods with a _ prefix are not added to the Actor class. This allows them to be defined as public but used only for internal purposes.
As we mentioned, the _failed hook can help in debugging a failed test. You have the opportunity to save the current test's state and show it to the user, but you are not limited to this.
Each module can output internal values that may be useful during debug. For example, the PhpBrowser module prints the response code and current URL every time it moves to a new page. Thus, modules are not black boxes. They are trying to show you what is happening during the test. This makes debugging your tests less painful.
To display additional information, use the debug and debugSection methods of the module.
Here is an example of how it works for PhpBrowser:
{% highlight php %}
debugSection('Request', $params); $this->client->request($method, $uri, $params); $this->debug('Response Code: ' . $this->client->getStatusCode()); ?>{% endhighlight %}
This test, running with the PhpBrowser module in debug mode, will print something like this:
{% highlight bash %}
I click "All pages"
- Request (GET) http://localhost/pages {}
- Response code: 200
{% endhighlight %}
Modules and Helpers can be configured from the suite config file, or globally from codeception.yml.
Mandatory parameters should be defined in the $requiredFields property of the class. Here is how it is done in the Db module:
{% highlight php %}
{% endhighlight %}
The next time you start the suite without setting one of these values, an exception will be thrown.
For optional parameters, you should set default values. The $config property is used to define optional parameters as well as their values. In the WebDriver module we use default Selenium Server address and port.
{% highlight php %}
'127.0.0.1', 'port' => '4444']; ?>{% endhighlight %}
The host and port parameter can be redefined in the suite config. Values are set in the modules:config section of the configuration file.
{% highlight yaml %}
modules: enabled: - WebDriver: url: 'http://mysite.com/' browser: 'firefox' - Db: cleanup: false repopulate: false
{% endhighlight %}
Optional and mandatory parameters can be accessed through the $config property. Use $this->config['parameter'] to get its value.
If you want to reconfigure a module at runtime, you can use the _reconfigure method of the module.
You may call it from a helper class and pass in all the fields you want to change.
{% highlight php %}
getModule('WebDriver')->_reconfigure(array('browser' => 'chrome')); ?>{% endhighlight %}
At the end of a test, all your changes will be rolled back to the original config values.
Another option to extend standard module functionality is to create a helper inherited from the module.
{% highlight php %}
{% endhighlight %}
In this helper you replace implemented methods with your own implementation.
You can also replace _before and _after hooks, which might be an option when you need to customize starting and stopping of a testing session.
If some of the methods of the parent class should not be used in a child module, you can disable them. Codeception has several options for this:
{% highlight php %}
{% endhighlight %}
Setting $includeInheritedActions to false adds the ability to create aliases for parent methods.
It allows you to resolve conflicts between modules. Let's say we want to use the Db module with our SecondDbHelper
that actually inherits from Db. How can we use seeInDatabase methods from both modules? Let's find out.
{% highlight php %}
seeInDatabase($table, $data); } } ?>{% endhighlight %}
Setting $includeInheritedActions to false won't include the methods from parent classes into the generated Actor.
Still, you can use inherited methods in your helper class.
There are lots of ways to create reusable and readable tests. Group common actions into one and move them to Actor class or Step Objects. Move CSS and XPath locators into PageObjects. Write your custom actions and assertions in Helpers. Scenario-driven tests should not contain anything more complex than $I->doSomething commands. Following this approach will allow you to keep your tests clean, readable, stable and making them easy to maintain.
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