PHPUnit: expects method meaning

expects() – Sets how many times you expect a method to be called:

$mock = $this->getMock('nameOfTheClass', array('firstMethod','secondMethod','thirdMethod'));
$mock->expects($this->once())
     ->method('firstMethod')
     ->will($this->returnValue('value'));
$mock->expects($this->once())
     ->method('secondMethod')
     ->will($this->returnValue('value'));
$mock->expects($this->once())
     ->method('thirdMethod')
     ->will($this->returnValue('value'));

If you know, that method is called once use $this->once() in expects(), otherwise use $this->any()

see:
PHPUnit mock with multiple expects() calls

https://phpunit.de/manual/current/en/test-doubles.html#test-doubles.stubs