Livewire: When running a test using ->set() ErrorException : Unresolvable dependency resolving is thrown

[basepack]

Describe the bug
Using PHP 7.4, Livewire 1.0.10 (latest), Laravel 7.x (latest)

 Livewire::test( Calculator::class )
                ->set( 'product', $product );

Returns:
ErrorException : Unresolvable dependency resolving [Parameter #0 [ <required> $product ]] in class App\Http\Livewire\Product\Calculator (View: /opt/project/vendor/livewire/livewire/src/views/mount-component.blade.php)

However, this runs fine:

  Livewire::test( Calculator::class, [ 'product' => $product ] );

To Reproduce

1. run: artisan make:model Product
2. run: artisan make:livewire Calculator
3. Add a public property $product and a mount() method in the Livewire Calculator component:

 public $product;

    public function mount( $product )
    {
        $this->product = $product;
    }

1. Create a test:

    /** @test */
    public function it_can_use_the_set_function_to_set_a_product()
    {
        /** @var Product $product */
        $product = factory( Product::class )->create();

        // Livewire::test( TestCalculator::class, [ 'product' => $product ] );  // <-- works
        Livewire::test( TestCalculator::class)
                ->set( 'product', $product );  // <-- error
    }

1. See the error: ErrorException : Unresolvable dependency resolving [Parameter #0 [ <required> $product ]] in class App\Http\Livewire\Product\Calculator (View: /opt/project/vendor/livewire/livewire/src/views/mount-component.blade.php)
2. Uncomment the // <-- works line, and see that pass.

Expected behavior
To be able to use the ->set() command, just like the docs tell us, instead of the inline version.

[GertjanRoke]

Hello @basepack, It's because you didn't give $product and default value like null or ''.
So that why you need to give it a second parameter while calling Livewire::test(..., [...]).

The ->set() function can be handy to check if certain side effects are done when you change the value later on and make assertions on it.

I hope this made it more clear why this happened. I think this is just the only way when the mount function doesn't have default values for the variables.

[calebporzio]

Exactly what Gertjan said. Thanks @GertjanRoke !

[galengidman]

@GertjanRoke I spent 2 hours on this tonight. Thanks for the help!