How to test the laravel passport api routes

I am on the latest Laravel with initial passport installation

In my test i have -

        $userEmail = '[email protected]';
        $userPassword = 'my-password';
        $userApiSecretName = 'token';
        $userApiSecretRedirect = 'https://test.com/callback';

        $user = factory(User::class)->create([
            'email'    => $userEmail,
            'password' => $userPassword,
        ]);

        $this->actingAs($user, 'api');

        $client = factory(Client::class)->state('password_client')->create([
            'user_id' => auth()->user()->id,
        ]);

        $response = $this->post('/oauth/token', [
            'form_params' => [ //with or without the 'form_params' part
                'grant_type'    => 'password',
                'client_id'     => $client->id,
                'client_secret' => $client->secret,
                'username'      => $userEmail,
                'password'      => $userPassword,
            ],
        ]);

I receive The authorization grant type is not supported by the authorization server

But works fine when I use it from the axios such as

axios.post('/oauth/token', {
                    grant_type:    'password',
                    client_id:     'the client id',
                    client_secret: 'the secret',
                    username:      '[email protected]',
                    password:      'my-password',
                })

From the test it does not work but from the axios works fine.

Any help will be appreciated. Thanks