Add a test helper for stubbing the submit method

[jackjennings]

I started working on a potential syntax for this, which I'll wrap up and post as a proposal in this issue.

[jackjennings]

To note: It would be helpful if this might also assert that a certain class of form was actually submitted, to ensure that the appropriate form is used.

[jackjennings]

Here's a potential implementation, though I don't know if the syntax is right. This also only stubs, without verifying:

class ActionDispatch::IntegrationTest
  def stub_submit form_kind, record
    controller = self.class.name.gsub(/Test\z/, "").constantize
    form = form_kind.new record

    controller.stub_any_instance :submit, form do
      yield form
    end
  end
end

class ValidForm < SimpleDelegator
  def valid?
    true
  end
end

class InvalidForm < SimpleDelegator
  def valid?
    false
  end
end

Which leads to the syntax in the test:

  test "should create client" do
    stub_submit ValidForm, @client do |form|
      post admin_clients_url(as: @account), params: { client_form: { name: @client.name } }
      assert_redirected_to admin_client_path(form)
    end
  end

  test "should not create invalid client" do
    stub_submit InvalidForm, @client do |form|
      post admin_clients_url(as: @account), params: { client_form: { name: @client.name } }
      assert_response :success
    end
  end

EDIT: fix missing variable assignment

[jackjennings]

I don't love the interface, but it mirrors the submit form_kind, record(, params) syntax (without the params).

This also falls apart if it were to also assert what kind of form is stubbed, since a reference to the form object class is never passed in.

Coming at it from the assert angle, an alternate syntax could be:

assert_submits ClientForm do
  post # ...
end
# or, optionally…
assert_submits ClientForm, stub: ValidForm.new(@client) do
  post # ...
end

[jackjennings]

Is it weird to assert and stub at the same time? I just don't want to end up with a bunch of nested blocks…

[ghost]

Hm, yeah, I do prefer the latter approach, as it's more readable to me as to what is going on, and I don't feel like I'm tracing the path towards what's happening. From an initial search, I can't see anything about whether or not people think this is weird. Hmmm