Using Parts of RSpec With Other Test Frameworks
Sometimes, you’ll want to use the powerful test doubles available in rspec-mocks, or the composable matchers provided by rspec-expectations, in a project where the rest of RSpec isn’t a good fit. For instance, you may already have an extensive test suite written in Minitest, or you may be writing acceptance tests in Cucumber.[124][125]
Both of these parts of RSpec are easy to use with other test frameworks, or even without a test framework at all. In fact, you’ve already done so in Parts of an Expectation and throughout Chapter 13, Understanding Test Doubles.
If you’re using Minitest, RSpec provides a couple of conveniences for you, including the following:
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Reporting unmet expectations correctly as Minitest assertion failures
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Making sure RSpec’s expect method doesn’t clash with Minitest’s method of the same name
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Verifying message expectations you’ve set on mock objects
To take advantage of this integration, require either or both of the following files in your tests:
| | require 'rspec/mocks/minitest_integration' |
| | require 'rspec/expectations/minitest_integration' |
Then, you can use RSpec’s test doubles and expectations freely in your Minitest suite:
| | class DinosaurTest < Minitest::Test |
| | def test_dinosaurs_fly_rockets |
| | dinosaur = Dinosaur.new |
| | rocket = instance_double(Rocket) |
| | expect(rocket).to receive(:launch!) |
| | dinosaur.fly(rocket) |
| | expect(dinosaur).to be_excited |
| | end |
| | end |
If you’re writing acceptance tests using Cucumber, you don’t need to do anything special to use RSpec-style expectations. Cucumber will detect when you’ve installed the rspec-expectations gem, and will automatically enable it.
We do not usually recommend using test doubles with the kinds of acceptance tests Cucumber is designed for, but Cucumber does offer rspec-mocks integration for those rare cases when you need it. To enable it, require ’cucumber/rspec/doubles’ in your environment setup.
To use parts of RSpec with another test framework, take a peek inside the two minitest_integration files from this example. They’ll give you a good starting point for integrating with your test framework.