Unit test

First we we will how to create a simple testing class testing a method.

For that first we will have to create a file from the name of the method inside the tests/Unit/inc folder and following the namespace from the class the method belongs to.

Example if we want to test the method my_method from the class Launchpad\Engine\MyNamespace\MyClass , we will create the file myMethod.php in the folder tests/Unit/inc/Engine/MyNamespace/MyClass.

Creating the class

Inside that class we will have then to add the following content:

• The namespace from your test that follows the path from your class in our example it is Launchpad\Tests\Unit\inc\Engine\MyNamespace\MyClass.

• The definition from the class with the following name Test_ followed by the name of the method, for your example will be Test_MyMethod.

• That class should be extending Launchpad\Tests\Unit\TestCase.

• Finally that class should contain a public method starting by test and that describe the usage from the test in your case it will be testReturnAsExpected .

namespace Launchpad\Tests\Unit\inc\Engine\MyNamespace\MyClass;

use Launchpad\Tests\Unit\TestCase;

class Test_MyMethod extends TestCase {

   public function testReturnAsExpected() {

   }

}

Mocking classes and functions

Now that we know how to create a class we will now learn how to deal with a class using other or with a class using some external function from WordPress for example.

Let’s imagine the class we want to test has the following content:

namespace Launchpad\Engine\MyNamespace\MyClass;

class {
  protected $dependency;

  public function __construct(\MyDependency $dependency) {
    $this->dependency = $dependency;
  }
 
  public function my_method() {
   $id = $this->dependency->method(12);
   $post = get_post($id);
  }
}

We will in this case to mock two things:

• The class MyDependency that our class use to use its interface without testing its content.

• The method get_post that my_method use to prevent use from re-implementing the method.

Mock a class

In this boilerplate we use Mockery to mock classes.

To mock a class with Mockery we use the Mockery::mock method this way:

$mock = Mockery::mock(MyDependency::class);

Once we got the mock object we can then set expectation this way:

$mock->expects()->method(12)->andReturn(45);

For more information on how Mockery work you can check their documentation.

Mock a function

To mock method in Rocker launcher we are using Brain Monkey.

Brain Monkey allows us to mock function with an interface close to Mockery.

To mock a function with Brain Monkey we can use the expects function this way:

use Brain\Monkey\Functions;

Functions\expect('get_post')->with(48)->once()->andReturn(false);

For more information on how Brain Monkey work you can check their documentation.