class SomeClassTest extends PHPUnit_Framework_TestCase { public function testSomeMethod() { // Create a mock object of SomeClass $mock = $this->getMockBuilder(SomeClass::class) ->getMock(); // Set expectations for the mock object $mock->expects($this->once()) ->method('someMethod') ->with($this->equalTo('Hello World')); // Call the method on the mock object $mock->someMethod('Hello World'); // Validate the expectations $mock->validate(); } }In the example above, we create a mock object of `SomeClass` and set expectations for the `someMethod` method. We then call the method on the mock object with the argument `"Hello World"`. Finally, we validate the expectations using the `validate` method. PHPUnit_Framework_MockObject_MockObject is part of the PHPUnit package library, which is a popular PHP unit testing framework.