@zoki I may be misunderstanding parts of your example, but here are my proposed solutions. The testing framework used (Pest or PHPUnit) is irrelevant as the same solutions work in both.

Clicking on a user's name opens a modal with their details.

Assuming this is determined based on a property set on the Livewire component, I would use Livewire's testing capabilities to set the property (or call the action that sets the property) and check that the page contains the user's details in the modal using assertSee.

Clicking Edit switches the modal's content to an edit form.

Assuming that you're using @if statements in blade to render the form or not, and assuming you're setting a $isEditing property in the component or similar, I would set that property in the test and use assertSee or assertSeeHtml to check that the form is rendered.

Save saves the data.

This one is the most straightforward. Fill the component with data in the test. Call the action that handles saving in your component. Check using $this::assertDatabaseHas or similar to ensure that your test database has been updated.

I would also attempt entering invalid data in tests and combine with assertHasErrors to ensure that your validation rules are configured correctly.

X closes the modal.

Call the action that "X" calls in the test. Ensure that the properties are reset to the expected state and combine with assertDontSeeHtml to make sure your template is rendered correctly.

If you're wanting to test the page itself in the same way a QA tester would, you'll want to reach for a tool like Laravel Dusk or Cypress, both of which are covered on Laracasts.

Hope that points you in the right direction!

Livewire 3 Has Rekindled My Interest