Steps

Step 1

First, create a orange model. By creating the model, a spec file will also be added to the models folder of the spec folder. Type this in the terminal:

rails generate model Orange

Then, run the migration to actually create the oranges table.

bundle exec rake db:migrate

Step 2

Then, run rspec.

bundle exec rspec

You will see a report with one pending test. When you generated your Orange model, RSpec also generated a matching spec file. Copy the test below into spec/models/orange_spec.rb and run 'bundle exec rspec' on the terminal again.

RSpec.describe Orange, :type => :model do
  context 'ActiveRecord associations' do
    it 'belongs to tree' do
      expect(Orange.reflect_on_association(:tree).macro).to be (:belongs_to)
    end
  end
end

Run 'bundle exec rspec'. This test fails! Let's add an associaton to our model. Add a belongs_to association to orange.rb:

class Orange < ActiveRecord::Base
  belongs_to :tree
end

Run 'bundle exec rspec' and now you should see one passing test! That's an example of an association test. Let's modify that test to fail. Then, run 'bundle exec rspec' and see what happens. Cool! Let's revert back to the passing test.

Step 3

Now let's write a has_many association test for the relationship between the Tree model and the Orange model! (hint: this doesn't exist yet so you'll have to create the model and migrate!)

On to controller tests! Just like the Orange model, you will create the OrangesController, which will also create spec files in the /spec/controllers folder of your app.

Step 4

First, create the oranges controller and relevant spec files by typing this in the terminal:

rails generate controller Oranges

Step 5

Then, run RSpec.

bundle exec rspec

You should see a report with some passing tests but those are just the model tests you wrote. So, let's add some controller tests! Copy the below test, paste it into the oranges controller spec file, create the relevant view files and then run 'bundle exec rspec' on the terminal again.

RSpec.describe OrangesController do
  context '#index' do
    it "renders the index view" do
      get :index
      expect(response).to render_template("index")
    end

    it "renders html" do
      process :index, method: :get
      expect(response.content_type).to eq "text/html"
    end
  end
end

You should see two failing tests. Hint: You'll need to add a route, index action, and a view. Not sure where to start? Read the errors in your failing tests for a hint. Run 'bundle exec rspec' after each change until both tests pass.

Note: as you write the controller tests, you may be prompted to install a missing gem called 'rails-controller-testing' to use the assert_template method. If prompted, please add it to your Gemfile and do a bundle install!

Step 6

Now, write another controller test for the new action (hint: you might need to look up what a mock is).

Step 7

Last but not least: view tests! Below is an short snippet of a possible Orange show HTML page you can create in your app:

<br>
Orange title: <%= @orange.name %>
<br>
<br>
Orange tree id: <%= @orange.tree_id %>
<br>

So, based on the orange you create, the show page should render HTML with the orange's name and tree id. Let's verify that with a few tests.

First, create a views folder in the spec folder. Then, create an oranges folder in the views folder. Lastly, create an oranges view spec file in the oranges folder. Type these commands in the terminal:

mkdir spec/views

mkdir spec/views/oranges

cd spec/views/oranges

touch show.html.erb_spec.rb

Step 8

Change directory back to the root directory of your app. Then, run rspec.

cd ../../..

bundle exec rspec

You should see a report with some passing tests but those are just the model and controller tests you wrote. So, let's add some view tests!

We're going to up the ante a bit here and NOT show you an example :) Google and StackOverflow are your friends here!