Minitest mock or stub methods


I’m building a small library to use in my Rails app which interacts with a 3rd party API. It fetches artists and tracks.

So I have:




To get an artist I do

artist = MyLib::Artist.find(“Oasis”)

Which returns an instance of Artist if it finds (via 3rd party API) it or nil otherwise.

Then I can call artist.tracks which fetches all available tracks at the 3rd party and returns them as an array.

In my artist class I have a separate method that makes the actual API calls and parses the XML response with Nokogiri

def self.find(name: nil)


doc = get_data(some_url)

More stuff…


def get_data(req_url)



When writing my tests I don’t want to hit the actual URL but instead load an XML file from disk.

I’m using Minitest which has a mocking library, but how do I actually mock (or is it more appropriate to stub?) the method?

Hello man,

I think you can easily accomplish this task declaring a variable, using to read a XML from your file system, and stubbing your method call on your test. This is the most common way of doing some tests with third party apis. But, if you want a more reliable way to do some test with API, I would recommended for you to try VCR. I am not a minitest guy, but I think VCR have setup to works fine with minitest too.

Have a nice day man

I suggest you use both WebMock and VCR. WebMock mocks out the HTTP calls the API code is doing, and lets VCR record the response the first time, and play it back from then on.