comments_spec.rb

require 'rails_helper'

RSpec.describe 'Comments API', type: :request do
  let!(:post) { create(:post) }
  let!(:comments) { create_list(:comment, 20, post_id: post.id) }
  let(:post_id) { post.id }
  let(:id) { comments.first.id }
  
  describe 'POST /posts/:post_id/comments' do
    let(:valid_attributes) { { body: 'Hello Body' } }

    context 'when the request is valid' do
      before { post "/posts/#{post_id}/comments", params: valid_attributes }

      it 'creates a post' do
        expect(json['body']).to eq('Great post')
      end

      it 'returns status code 201' do
        expect(response).to have_http_status(201)
      end
    end

    context 'when the request is invalid' do
      before { post "/posts/#{post_id}/comments", params: {} }

      it 'returns status code 422' do
        expect(response).to have_http_status(422)
      end

      it 'returns a failure message' do
        expect(response.body).to match(/Validation failed: Body can't be blank/)
      end
    end
  end

end

posts_spec.rb

require 'rails_helper'

RSpec.describe 'Posts API', type: :request do
  let!(:posts) { create_list(:post, 10) }
  let(:post_id) { posts.first.id }
  
  # POST /posts
  describe 'POST /posts' do
    let(:valid_attributes) { { title: 'Hello Body', description: "Hella yella, Shrek. Lol kek cheburek. Who's lovin' weed? Pussy money weed." } }

    context 'when the request is valid' do
      before { post '/posts', params: valid_attributes}

      it 'creates a post' do
        expect(json['title']).to eq('Hello Body')
        expect(json['description']).to eq("Hella yella, Shrek. Lol kek cheburek. Who's lovin' weed? Pussy money weed.")
      end

      it 'returns status code 201' do
        expect(response).to have_http_status(201)
      end
    end

    context 'when the request is invalid' do
      before { post '/posts', params: { title: 'Hey man' } }

      it 'returns status code 422' do
        expect(response).to have_http_status(422)
      end

      it 'returns a validation failure message' do
        expect(response.body)
          .to match(/Validation failed: Description can't be blank/)
      end
    end
  end

end

routes.rb

.....................  
resources :posts do
  resources :comments
end
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