Failed with test

I have such test:

    public function testUpdate()
{
    $user = factory(User::class)->create([
        'id' => 1,
        'role_id' => 1,
    ]);
    factory(User::class)->create([
        'id' => 2,
        'username' => 'Test_username',
    ]);
    $this->patch('/api/users/2', [
        'username' => 'Test',
        'profile' => [
            [
                'bio' => 'Test_bio',
            ],
        ],
    ], ['authorization' => "Bearer {$user->api_token}"])->assertJson([
        'username' => 'Test',
    ]);
    $this->get('/api/users/2?fields=*,profiles.*', [
        'accept' => 'application/json',
    ])->assertJson([
        'username' => 'Test',
        'profile' => [
            [
                'bio' => 'Test_bio',
            ],
        ],
    ]);
}

It's test update for user and relatinhipmodel profile. But I have error:

    1) Tests\Feature\Controllers\UserTest::testUpdate
Symfony\Component\Debug\Exception\FatalThrowableError: Method name must be a string

Method update work, I test it manually on Postman and frontend. Problem in test code.