How to Run a Single Test From a Rails Test Suite?

When working on a Ruby on Rails application, testing is an essential part of the development process. Rails provides a powerful testing framework, and sometimes you might want to run only specific tests rather than the entire suite. In this blog post, we’ll explore how to run specific tests in Rails using different commands and options.

Running a Single Test File

If you have a test file for your users controller located at test/controllers/users_controller_test.rb (See below screenshot for reference).

you can run this specific test file using either of the following commands:

Command 1:

rails test test/controllers/users_controller_test.rb

Command 2:

rake test test/controllers/users_controller_test.rb

Running a Specific Test Method/Test Case with Method Name

To run a specific test method within a test case file, specify the method name. For example, if there’s a test case with the name “should get new” at line 13(See in attached screenshot), you can run it using either of the following commands:

Command 1:

rails test test/controllers/users_controller_test.rb -n "should get new"

Command 2:

rails test test/controllers/users_controller_test.rb -n should_get_new

Replace should_get_new or “should get new” with the actual name of the test method’s name you want to run.

Running a Specific Test Method/Test Case at a Line Number

If you want to run a specific test case or a test within a file, provide the line number where the test is defined. For example:

Command :

rails test test/controllers/users_controller_test.rb:13

Replace 13 in the commands with the line number where the specific test method is defined. This helps you pinpoint and execute a particular test within the file.

These commands will execute the specified tests and provide you with detailed test results and output.

In Addition, To run all application test suites, you can use following command:

Command :

rails test
Keep in mind that Rails test files and methods typically follow a naming convention. Utilize auto-completion to quickly find the path to a specific test file or method in your project.

By using these commands and options, you can efficiently run specific tests in your Rails application, making your testing process more targeted and effective. Happy testing!

Note:

While rake can run all or specific file test cases, if you want to run a specific test case or a test at a specific line number in a file, it’s recommended to use the rails command instead of rake.