Remove non-Rails-5 features from controller spec scaffold

[CodingItWrong]

Fixes #1605 by removing all expectations for assigns and templates rendered from the controller specs generated for scaffolds. Sample generated spec below.

They feel a big lethargic because all that’s being specified for a lot of the methods now is only that they return HTTP success—but I believe that’s all there is to specify for them in a vanilla Rails 5 install.

A few other things we could consider:

• Generating commented out “assigns” and “template rendered” expectations, along with a comment explaining the rails-controller-testing gem.
• Detecting whether “assigns” and “template rendered” expectations are available (i.e. a Rails 4 app, or a Rails 5 app with the rails-controller-testing gem), and generating the appropriate expectations then. That would significantly increase the complexity of the controller spec template.

Happy to take this PR any direction y’all would like—let me know how I can help!

Here’s a sample of the generated spec, which passes once I take care of the skips:

require 'rails_helper'

# (header comments trimmed)

RSpec.describe PostsController, type: :controller do

  # This should return the minimal set of attributes required to create a valid
  # Post. As you add validations to Post, be sure to
  # adjust the attributes here as well.
  let(:valid_attributes) {
    skip("Add a hash of attributes valid for your model")
  }

  let(:invalid_attributes) {
    skip("Add a hash of attributes invalid for your model")
  }

  # This should return the minimal set of values that should be in the session
  # in order to pass any filters (e.g. authentication) defined in
  # PostsController. Be sure to keep this updated too.
  let(:valid_session) { {} }

  describe "GET #index" do
    it "returns a success response" do
      post = Post.create! valid_attributes
      get :index, params: {}, session: valid_session
      expect(response).to be_success
    end
  end

  describe "GET #show" do
    it "returns a success response" do
      post = Post.create! valid_attributes
      get :show, params: {id: post.to_param}, session: valid_session
      expect(response).to be_success
    end
  end

  describe "GET #new" do
    it "returns a success response" do
      get :new, params: {}, session: valid_session
      expect(response).to be_success
    end
  end

  describe "GET #edit" do
    it "returns a success response" do
      post = Post.create! valid_attributes
      get :edit, params: {id: post.to_param}, session: valid_session
      expect(response).to be_success
    end
  end

  describe "POST #create" do
    context "with valid params" do
      it "creates a new Post" do
        expect {
          post :create, params: {post: valid_attributes}, session: valid_session
        }.to change(Post, :count).by(1)
      end

      it "redirects to the created post" do
        post :create, params: {post: valid_attributes}, session: valid_session
        expect(response).to redirect_to(Post.last)
      end
    end

    context "with invalid params" do
      it "returns a success response (i.e. to display the 'new' template)" do
        post :create, params: {post: invalid_attributes}, session: valid_session
        expect(response).to be_success
      end
    end
  end

  describe "PUT #update" do
    context "with valid params" do
      let(:new_attributes) {
        skip("Add a hash of attributes valid for your model")
      }

      it "updates the requested post" do
        post = Post.create! valid_attributes
        put :update, params: {id: post.to_param, post: new_attributes}, session: valid_session
        post.reload
        skip("Add assertions for updated state")
      end

      it "redirects to the post" do
        post = Post.create! valid_attributes
        put :update, params: {id: post.to_param, post: valid_attributes}, session: valid_session
        expect(response).to redirect_to(post)
      end
    end

    context "with invalid params" do
      it "returns a success response (i.e. to display the 'edit' template)" do
        post = Post.create! valid_attributes
        put :update, params: {id: post.to_param, post: invalid_attributes}, session: valid_session
        expect(response).to be_success
      end
    end
  end

  describe "DELETE #destroy" do
    it "destroys the requested post" do
      post = Post.create! valid_attributes
      expect {
        delete :destroy, params: {id: post.to_param}, session: valid_session
      }.to change(Post, :count).by(-1)
    end

    it "redirects to the posts list" do
      post = Post.create! valid_attributes
      delete :destroy, params: {id: post.to_param}, session: valid_session
      expect(response).to redirect_to(posts_url)
    end
  end

end

[JonRowe]

/cc @samphippen

[fables-tales]

LGTM