Test Error - Call to a member function getId() on null

it('can render product category page', function () {

    $this
        ->actingAs(user())
        ->get(ProductCategoryResource::getUrl())
        ->assertSuccessful();
});

it('can render product category page', function () {

    $this
        ->actingAs(user())
        ->get(ProductCategoryResource::getUrl())
        ->assertSuccessful();
});