Raise an error in PHPunit when calling createMock where createStub is enough

[ChinaskiJr]

Feature request

Hi !

In order to enforce and clarify the usage of test doubles for everyone, I would like to know if you think it would be beneficial to implement a rule that raises an error when a mock is created without any assertions on being called (essentially making it a stub).

This rule would only be about using the correct terminology for test doubles. It should help to better understand what is going on in our test, and what is our intention.

https://docs.phpunit.de/en/10.5/test-doubles.html

In example :

<?php
// This will raise an error : 
public function testSomething(): void 
{
    $stub = $this->createMock(Foo::class);
    $stub->method('foo')->willReturn('bar');
   
    self::assertSame('bar', $stub->foo());
}

// This won't raise an error : 
public function testSomething(): void 
{
    $stub = $this->createStub(Foo::class);
    $stub->method('foo')->willReturn('bar');
   
    self::assertSame('bar', $stub->foo());
}

// This won't raise an error : 
public function testSomething(): void 
{
    $mock = $this->createMock(Foo::class);
    $mock->expects($this->once())->method('foo')->willReturn('bar');
   
    self::assertSame('bar', $mock->foo());
}

I can try to make a PR for this, but before working on it, I prefer to ask if you think it would be a good improvement.