Harper: Dead-simple, out-of-process, HTTP mocks

To mock a service using as Harper, POST a mock definition to Harper before making your request. It's simple, and you've probably written something similar a half-dozen times. Well, you don't need to anymore.

You might be interested in using Harper when you're building an app that depends on an HTTP service, but you can't mock it out in-process. For example, a single page JavaScript app running in a mobile browser.

Ruby Client API

Unfortunately there aren't yet interfaces to Harper from other languages.

  • Use HarperClient::start to start the Harper service in the background.

  • Use HarperClient::stop to stop the background service.

These two calls do start and stop another Ruby interpreter running in the background, so you might want to run these at the beginning and the end of your cucumber run, rather than before and after every scenario.

This interface is incomplete. It is also possible to delete a mock. This can be done by deleting the URL provided in the Location header when creating a new mock.

If you require more control of Harper, or you want to support a new language, check out features/mock_http_rpc_service.feature. And pull requests are always welcomed.

Defining Mocks

Use HarperClient::mock to define a new mock. This method takes a hash defining the mock. If a mock has already been defined for a URL, Harper will silently replace it with the new mock.

  • url: The URL path to mock out. This also identifies the mock. Required.

  • method: The HTTP method to respond to. Required.

  • status: The HTTP status code to provide. Optional. Defaults to 200.

  • content_type: What content-type header to set when responding with the mock. Required.

  • body: A string to be used as the HTTP response body. Required.

  • delay: A delay to include when responding to the mock, in milliseconds. Optional. Defaults to no delay.

Typical Use

  1. Start Harper at the very start of your test run.
  2. In the Given steps or Background for your scenarios, define the mocks that will be required for that scenario. If a similar mock has already been defined, Harper will silently replace it.
  3. At the very end of your test run, stop Harper.

That's it.