Features, scenarios, and steps

To use Cucumber, you'd first separate your platform into multiple features; then, within each feature, you'd define scenarios to test for. For us, we can take the "Create user" requirement as one feature, and start breaking it down into scenarios, starting with the following:

• If the client sends a POST request to /users with an empty payload, our API should respond with a 400 Bad Request HTTP status code and a JSON object payload containing an appropriate error message
• If the client sends a POST request to /users with a payload that is not JSON, our API should respond with a 415 Unsupported Media Type HTTP status code and a JSON response payload containing an appropriate error message
• If the client sends a POST request to /users with a malformed JSON payload, our API should respond with a 400 Bad Request HTTP status code and a JSON response payload containing an appropriate error message

We will define more scenarios later, but let's focus on these three to get us started.

Each feature should be defined, using the Gherkin language, within its own .feature file. So, let's create one now.

$ cd <project-root-dir>
$ mkdir -p spec/cucumber/features/users/create
$ touch spec/cucumber/features/users/create/main.feature

Now, let's translate the scenarios for our Create User feature into Gherkin.