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 (e.g. C-u C-c C-t l), CIDER will prompt for test selector filters and only run those tests that match the selector inclusions/exclusions.
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. It will also work for implementation functions, by searching for a matching test namespace with a matching deftest name.
You can configure CIDER’s test execution behavior in multiple ways.
Starting from 1.8.0, CIDER has standard fail-fast functionality,
controlled by the
cider-test-fail-fast defcustom (default
You can toggle its value for the current buffer using
C-c C-t f or
C-c C-t C-f)
|fail-fast will never be chosen for the "retest" functionality, since that would cause you to lose the majority of the tests that previously failed.|
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)
If you have selectors you want
automatically applied, you can set the variables
to a list of strings to use. The following is an example of setting the default exclude
selectors so that tests tagged as "integration" or "flakey" don’t run.
(setq cider-test-default-exclude-selectors '("integration" "flakey"))
|You’ll generally want to place default selectors in your project configuration, as opposed to your global configuration.|
By default the test report is displayed only when there are test failures or errors. 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)
Sometimes, for fine-grained integrations or debugging, you might want to run an arbitrary callback whenever the tests fail due to an exception.
For this, you can safely redefine
using vanilla Clojure; please refer to its docstring for more details.
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.