Testing Trailblazer applications usually involves the following tests.

  1. Unit tests for operations. They test all edge cases in a nice, fast unit test environment without any HTTP involved.
  2. Integration tests for controllers. These Smoke tests only test the wiring between controller, operation and presentation layer. Usually, a coded click path simulates you manually clicking through your app and testing if it works.

    The preferred way here is using Rack-test and Capybara.

  3. Unit tests for cells. By invoking your cells with arbitrary data you functionally test the rendered markup using Capybara.


Even though the Trailblazer book uses MiniTest for its test suite, Trailblazer can be tested with any framework. Usually, this will be Rspec.

Invoking operations works identical to MiniTest.

describe Comment::Create do
  it "creates comment" do
    op = Comment::Create.(comment: {body: "Rspec rocks!"})
    expect(op.model.body).to eq("Rspec rocks!")

You’re free to use your matchers, your testing style, your way of structuring describe or specify, and so on.

!!! TODO: Example for smoke tests.

To write unit tests for your cells, please install the rspec-cells gem.

describe Comment::Cell, type: :cell do
  let (:comment) { Comment::Create.(comment: {body: "Rspec rocks!"}) }
  subject { concept(:comment, comment).(:show) }

  it { expect(subject).to have_content "Rspec rocks!" }

Learn more about Rspec and Cells.