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.
|CIDER only supports clojure.test and other libraries providing integration with clojure.test. Native support for other libraries might be available via CIDER plugins.|
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.
|CIDER will only run tests that have been loaded (evaluated). This means that prior to running some tests you always have to evaluate them first. As a corollary - if you make some changes to a test, you’ll have to re-evaluate it, so that CIDER will pick up the updated version.|
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.
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
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.
You can configure CIDER’s test execution behavior in multiple ways.
Test Namespace Naming Convention
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. Here’s how you can configure the test running
to look for
some.test-ns instead of
(defun cider-custom-test-ns-fn (ns) "For a NS, return the test namespace, which may be the argument itself. This uses the convention of prepending 'test-' to the namespace name." (when ns (let ((prefix "test-")) (if (string-prefix-p prefix ns) ns (concat prefix ns))))) (setq cider-test-infer-test-ns #'cider-custom-test-ns-fn)
Macros Used to Define Tests
If your individual tests are not defined by
defspec, CIDER will
not recognize them when searching for a test at point in
You can customize the variable
cider-test-defining-forms to add additional
forms for CIDER to recognize as individual test definitions.
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:
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.