Add assert_react_component method for test react_component render result

[huacnlee]

test 'assert_react_component' do
  get "/pages/1"
  assert_equal 200, response.status
  assert_react_component "GreetingMessage"
  assert_react_component "GreetingMessage" do |props|
    assert_equal "Bob", props[:name]
    assert_equal "Last Bob", props[:last_name]
    assert_equal "Bob", props[:info][:name]

    assert_select "[id=?]", "component"
    assert_select "[class=?]", "greeting-message"
  end
end

[BookOfGreg]

This is a wonderful submission, well written and useful.
Thank you for the contribution!
I have a couple comments that might be able to improve it further and I'd welcome your thoughts on those points.

[BookOfGreg]

This is good work. I will need to look into why the tests are failing before merge, based on the current Travis-ci run 1505 and 1506 but then OK to merge.

Edit:
Looks like the first set of failures in 1505 is maybe scope related, the ones in 1506 maybe a problem with the autoloader in different rails versions. I may be able to look into this later as I recognise that the test suite for this gem can be quite complex at times.

[huacnlee]

@BookOfGreg ActiveSupport.on_load(:action_dispatch_integration_test) was coming from Rails 5.0.0, so 4.2 not support that.

See here example of ActionMailer:

rails/rails@9a64293

How a about here change to:

ActiveSupport.on_load(:action_view) do
  include ::React::Rails::ViewHelper
  ActionDispatch::IntegrationTest.send :include, React::Rails::TestHelper
end

[BookOfGreg]

If it's good enough for Rails, it's good enough for me :) I'll accept that suggestion.

[huacnlee]

@BookOfGreg just updated

[BookOfGreg]

I'll clean up whatever is wrong with the test suite. Thank you for the contribution. I'll try get a release out in the coming weeks.

[cacods]

Is it possible to use assert_react_components for components inside the main component called with render_component helper?

[eelkevdbos]

@cacods, I expect you need a feature test for this because it would involve actually initializing the server rendered dom elements into full react components.

The current assert_react_components helper does only asserts the existence of a div[data-react-class=?] with the expected properties through inspection of the data-react-props attribute.