Subcutaneous Testing

If a unit test is testing the smallest testable component of application code, then a subcutaneous test is a single workflow which can be identified and tested of the application code. Subcutaneous testing treats a workflow as a testable unit.

Why subcutaneous testing over traditional unit testing?

Advantages:

• Reduced coupling between implementation and tests
• Improve ease of refactoring
• Reduce cost of evolving design
• Brings business-focus to developers
• Reduce need for brittle end-to-end tests

Disadvantages:

• More setup
• Hard to focus on a unit of work
• Debugging tests
• Decide when to add complementary unit tests is subjective

Prepare for the exercise

Install dependencies

$ yarn

Familiarize with the todos application at http://localhost:3000

$ yarn start

Run the test

$ yarn test

All the unit tests should pass.

Now Identify different workflow in the application and for each of them you will write a subcutaneous test. When you are ready to start, open the todos.workflows.spec.js and start to write your first subcutaneous test.

If you cannot identify any user workflow here are a couple to get you started:

First flow (Basic usage)

• user type a todo
• user click the add todo button
• user see the added todo in the list
• user click on todo to mark it as completed
• user see the todo marked as completed

Second flow (Visibility Filters)

• user type a todo (todo one)
• user click the add todo button
• user type another todo (todo two)
• user click the add todo button
• user click on (todo one) to mark it as completed
• user click on active filter
• user only see (todo two)
• user click on completed filter
• user only see (todo one)
• user click on all filter
• user see all todos

You can find an implementation of the subcutaneous tests in the branch named solution (only with enzyme).