PHPUnit - 调用Assert trait方法

Question

Supposing I have a trait which currently has a method:

trait MyTrait
{
    public function traitMethod()
    {
        return true;
    }
}

Now let's say this trait is used by several classes but I don't want to write a unit-test for every class. Instead I want to write a single unit-test only for the trait:

public function testTraitMethod()
{
    $trait = $this->getMockForTrait(MyTrait::class);
    $this->assertTrue($trait->traitMethod());
}

But the problem is that a class may actually override trait's method:

class MyClass
{
    use MyTrait;

    public function traitMethod()
    {
        return false;
    }
}

In this case MyClass is doing something wrong but I'm not aware of it since I'm testing only the trait.

My idea would be write a single unit-test for every class just to check if it's using that trait and it's not overriding that method. If a class needs to override trait's method then it needs a specific unit-test as well.

Currently I'm writing unit-tests for each class that implements my trait but it's of course kind of copy-paste tests everywhere.

So is there a way to test if a class calls it's underlying trait method?

Answer 1

I found a solution using Reflection, I'll post it in case someone needs it because I couldn't find anything related to my problem. Feel free to comment or add different solutions if you want.

So the following test asserts that $serviceClass uses $traitClass and doesn't override methods declared in $traitClass except abstract ones and those which are manually added to $overriddenMethods array.

public function testServiceUsesTrait()
{
    $serviceClass = MyClass::class;
    $traitClass = MyTrait::class;

    $this->assertContains($traitClass, (new \ReflectionClass($serviceClass))->getTraitNames());

    $reflectedTrait = new \ReflectionClass($traitClass);
    $reflectedTraitFile = $reflectedTrait->getFileName();

    /**
     * If $serviceClass overrides some trait methods they
     * should be inserted into this array to avoid test failure.
     * Additional unit-tests should be written for overridden methods.
     */
    $overriddenMethods = [];

    foreach ($reflectedTrait->getMethods() as $traitMethod) {
        if ($traitMethod->isAbstract() || in_array($traitMethod->getName(), $overriddenMethods, true)) {
            continue;
        }
        $classMethod = new \ReflectionMethod($serviceClass, $traitMethod->getName());
        $this->assertSame($reflectedTraitFile, $classMethod->getFileName(), sprintf(
            'Trait method "%s" is overridden in class "%s" thus it must be excluded from this test.',
            $traitMethod->getName(), $serviceClass
        ));
    }
}

I also tried to compare declaring classes using $classMethod->getDeclaringClass() instead of comparing filenames but it didn't work: even if trait method is not overridden in class, getDeclaringClass() always returns the class itself.