Rails Testing Exercises / Testing Fundamentals Write A Controller Spec

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This coding exercise comes from Upcase, the online learning platform we run. It's part of the Rails Testing Exercises course and is just one small sample of all the great material available on Upcase, so be sure to visit and check out the rest.

Exercise Intro

Integration tests are great for catching bugs, but they can be cumbersome for testing simple if/else branches and little details. For those, you'll want to use "unit tests," tests which exercise a single class working by itself.

When writing these unit tests, you'll want to use "test doubles:" test objects which stand in for the objects you'd use in a real application.

In this example, you'll write a unit test to make sure the create action for PeopleController works as expected based on the return value of save.

When writing controller specs, you'll use the get, post, put, and delete methods to exercise actions in your controller:

# Run the `index` action for the current controller.
# `params[:user_id]` will be `"6"`.
get :index, user_id: "6"

You can use matchers from rspec-rails to verify the responses rendered by your controllers:

# Expect: `redirect_to root_path`
expect(response).to redirect_to(root_path)

# Expect: `render :new`
expect(response).to render_template(:new)

Once you get this test working, try using test doubles so that you don't depend on the actual validations in Person.

Here are some examples of stubs:

allow(Post).to receive(:new).and_return(fake_post)
allow(fake_post).to receive(:update_attributes).
  with(title: "hello").
  and_return(true)

You can see more examples of stubbing in the rspec-mocks documentation.

Instructions

To start, you'll want to clone and run the setup script for the repo

git clone git@github.com:thoughtbot-upcase-exercises/testing-fundamentals-write-a-controller-spec.git
cd testing-fundamentals-write-a-controller-spec
bin/setup

1. Edit spec/controllers/people_controller_spec.rb.
2. Write tests for the success and failure cases.
3. Make sure your tests are passing by running rake.

Featured Solution

Check out the featured solution branch to see the approach we recommend for this exercise.

Forum Discussion

If you find yourself stuck, be sure to check out the associated Upcase Forum discussion for this exercise to see what other folks have said.

Next Steps

When you've finished the exercise, head on back to the Rails Testing Exercises course to find the next exercise, or explore any of the other great content on Upcase.

License

testing-fundamentals-write-a-controller-spec is Copyright © 2015-2018 thoughtbot, inc. It is free software, and may be redistributed under the terms specified in the LICENSE file.

Credits

This exercise is maintained and funded by thoughtbot, inc.

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