How to mock properly IlluminateHttpRequest class from Laravel

I’m trying to test a method from a class which contains a method using the request() helper from Laravel. This is the method:

Category class

public function getCanonicalUrl()
{
    return preg_match('//sale/./', request()->getRequestUri())
         ? ''
         : url($this->getUrlKey());
}

The test should make this helper to catch properly the URI when doing getRequestUri() but it’s actually returning an empty string. This is one of the thousand tries that I gave to the test.

Test

public function testCanonical()
{
    // ...

    $requestMock = Mockery::mock(Request::class)
      ->shouldReceive('getRequestUri')
      ->andReturn('/sale/random-string');

    $this->app->instance(Request::class, $requestMock);

    // ...
}

Any ideas of how this could be achieved? Thanks in advance.

Answer

You should not mock the Request facade. Instead, pass the input you desire into the HTTP helper methods such as get and post when running your test.

https://laravel.com/docs/5.5/mocking#mocking-facades