PHPUnit - how to set expectations against exact methods calls

ExactMethodExpectation.php

<?php

$mock = $this->createMock(SomeDependency::class);
$mock->expects($this->once())->method('firstMethod')->willReturn('something');
$mock->expects($this->once())->method('secondMethod')->willReturn('something else');

$cut = new SomeClass($mock)
$cut->act();

// how to ensure there's no method called other than the 2 above?
// I'm using workaround like so currently:
$mock->expects($this->never())->method(
  $this->logicalNot(
    $this->in('firstMethod', 'secondMethod')
  )
);

// 'in' is a custom constraint:
// in_array($other, ...$items)

// -------------------------------------

// SomeClass
public function act()
{
  $this->dependency->firstMethod(); // okay
  $this->dependency->secondMethod(); // okay
  
  $this->dependency->anotherMethod(); // test should fail at this call
}