Unit and Functional Tests

A unit test is about testing a single function/method in isolation with all of its possible outputs.

A functional test is about testing a single functionality, which can span multiple methods and a controller.

Other common terms in Rails are "model tests," "controller tests," and others.

You can find model tests in spec/models, controller tests in spec/controllers and additional functional tests in various directories within the spec directory.

You can run all models tests, for example, with:

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bundle exec rspec spec/models

To run an individual file you can use, for example:

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bundle exec rspec spec/models/user_spec.rb

To run a specific test case you can use, for example:

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bundle exec rspec spec/models/user_spec.rb:10

where 10 is the line number of the test case that you want to execute.

Testing Controllers

Historically, it has been common to use Rspec to write tests for Rails controllers. This pattern isn't necessarily discouraged in the DEV codebase, but Rspec has introduced a more effective way to test controllers via Request Specs.

Request specs test the actions on a controller across the entire stack, effectively acting as Integration Tests. You can read more about request specs in our documentation on Integration Tests.

You can read the official guide Testing Rails Applications to learn more.