The Clojure ecosystem provides a lot of support for test-driven development (TDD) and other test-centric patterns. First, Clojure provides a standardized framework for developing tests called clojure.test. Many other testing libraries plug into this framework. Second, tools like Leiningen create standardized application and library project structures that provide locations and idiomatic naming for test code. Finally, CIDER provides several easy ways to run these tests, view the test results, and quickly jump to code that is failing to pass a given test.

Note

CIDER only supports clojure.test and other libraries providing integration with clojure.test.

Running Tests

CIDER has several functions that help you run all your tests or a selected subset of them. All of the CIDER test commands are available in both source code and REPL buffers. In REPL buffers you can also use , to invoke some of the testing commands.

First, you can run all the tests in your project with C-c C-t p or C-c C-t C-p. It's important to realize that this will load all the namespaces in your project, which might be more than you're expecting.

You can run all loaded tests with C-c C-t l or C-c C-t C-l.

If you invoke either of these commands with a prefix CIDER, will prompt for test selector filters and only run those tests that match the selector inclusions/exclusions.

Test developers use selectors to define subsets of the total test suite that are run together for different testing tasks. For example you can mark some of your tests with the ^:smoke metadata marker and others with ^:integration. This enables you to run these tests separately in your build pipeline. CIDER helps you to run these same test subsets in your development environment.

Test selectors were originally a leiningen feature and you can get more information by executing:

$ lein help test

You can run all the tests in the current namespace, whether specified by a source file or by the REPL, using C-c C-t n or C-c C-t C-n. Note that it's idiomatic for Clojure projects to locate tests in a separate namespace than the code that is being tested. CIDER uses a simple algorithm to figure out where the tests are located. The algorithm works as follows. If you're in an implementation namespace (e.g. some.ns), CIDER will try to find a matching test namespace (by default some.ns-test) and run the tests there. But if you're in something that already looks like a test namespace (e.g. some.ns-test), CIDER will simply run the tests in that namespace. If you have put some of your tests into your implementation namespace, using clojure.test/with-test, for instance, you might want to suppress the namespace inference logic and force CIDER to run tests in the current namespace unconditionally. You can do this by adding a prefix to the namespace commands: C-u C-c C-t C-n. This will simply run whatever tests are present in the currently visited or active namespace.

You can also run a subset of the tests defined in the namespace, filtered by test selectors, using C-c C-t C-s. CIDER will prompt for the selectors in the minibuffer. If you call this command with a prefix (C-u C-c C-t C-s) you can suppress the namespace inference logic as for C-u C-c C-t C-n

Finally, you can execute the specific test at the point using C-c C-t t or C-c C-t C-t.

Interacting with Test Result Reports

After running your tests, CIDER displays a test result report in the *cider-test-report* buffer. This buffer uses test-report-mode, which makes it easy to review any failures that might have occurred and jump directly to the definition of failing tests.

Keyboard shortcut Description
g Run test at point.
n Run tests for current namespace.
s Run tests for current namespace with selector filter.
l Run tests for all loaded namespaces.
p Run tests for all project namespaces. This loads the additional namespaces.
f Re-run test failures/errors.
M-p Move point to previous test.
M-n Move point to next test.
t or M-. Jump to test definition.
d Display diff of actual vs expected.
e Display test error cause and stacktrace info.

Configuration

You can configure CIDER's test execution behavior in multiple ways.

If your tests are not following the some.ns-test naming convention you can set the variable cider-test-infer-test-ns to a function that takes the current namespace and returns the matching test namespace (which may be the same as the current namespace). This provides complete flexibility to structure your test suite using whatever conventions you might want.

If your individual tests are not defined by deftest or defspec, CIDER will not recognize them when searching for a test at point in cider-test-run-test. You can customize the variable cider-test-defining-forms to add additional forms for CIDER to recognize as individual test definitions.

If you want to view the test report regardless of whether the tests have passed or failed:

(setq cider-test-show-report-on-success t)

Running Tests Automatically (Test-Driven Development)

CIDER provides a minor-mode that automatically runs all tests for a namespace whenever you load a file (with C-c C-k). You can toggle it manually with M-x cider-auto-test-mode, or you can use:

(cider-auto-test-mode 1)

This is identical to manually typing C-c C-t C-n every time you load a Clojure buffer. As described previously, CIDER will try to automatically determine the namespace containing the tests.

Using cider-test with Alternative Test Libraries

The clojure.test machinery is designed to be pluggable. Any test library can integrate with it and leverage the cider-test ecosystem.

As a test framework author, supporting the built-in clojure.test machinery (and hence cider-test) is pretty straightforward:

  1. Add :test metadata to the vars corresponding to the test functions. The clojure-test machinery uses this metadata to find tests.
  2. Implement the clojure.test/report multimethod to capture the test results.

For example, test.check was designed independently of clojure.test but integrates with it. Because of this, cider-test handles defspec just like deftest. test.check just adds compatibility in this namespace.

Supported Libraries