PHPUnit : Assert a parameter when pass it to mock object

You can use ->with($this->callback()) and pass in a closure to perform more complex assertions on the argument.

From the PHPUnit Docs

The callback() constraint can be used for more complex argument verification. This constraint takes a PHP callback as its only argument. The PHP callback will receive the argument to be verified as its only argument and should return TRUE if the argument passes verification and FALSE otherwise.

Example 10.13: More complex argument verification

getMock('Observer', array('reportError'));

    $observer->expects($this->once())
             ->method('reportError')
             ->with($this->greaterThan(0),
                    $this->stringContains('Something'),
                    $this->callback(function($subject){
                      return is_callable(array($subject, 'getName')) &&
                             $subject->getName() == 'My subject';
                    }));

    $subject = new Subject('My subject');
    $subject->attach($observer);

    // The doSomethingBad() method should report an error to the observer
    // via the reportError() method
    $subject->doSomethingBad();
} } ?>

So your test would become:

$mockObject->expects($this->at(0))
->method('search')
->with($this->callback(
    function ($config){
        if(!isset($config['shouldnothere']) && $config['object']->isValidValue()) {
            return true;
        }
        return false;
    })
->will($this->returnValue([]));

You can use Mockery for it

Say I have a code

$productValidator = app(ProductValidator:class)->setProduct($productIn);

That would be the test code

use Mockery;

...

    $productValidator            
        ->shouldReceive('setProduct')->once()
        ->with(Mockery::type(Product::class))
        ->with(Mockery::on(function($productIn) use ($productId) {
                return $productIn->id === $productId;
            }))
        ->andReturn($productValidator);

Tested on phpunit "version": "8.5.8"