circleci.test

A Clojure test-runner compatible with tests written using clojure.test.

Keep your existing deftests, but gain flexibility around how you run them.

Usage

Add [circleci/circleci.test "0.5.0"] to your :dependencies under :dev.

It's recommended to use this set of Leiningen aliases:

:aliases {"test" ["run" "-m" "circleci.test/dir" :project/test-paths]
          "tests" ["run" "-m" "circleci.test"]
          "retest" ["run" "-m" "circleci.test.retest"]}

You can pass a selector to lein test (see below) or run just a list of individual tests with lein tests my.test.ns my.other.test.ns.

From inside a repl, you can run all loaded test namespaces with (circleci.test/run-tests) or pass in a list of symbols to just test a few namespaces. Run individiual tests with (circleci.test/test-var #'my.test.ns/my-test).

Selectors

As with Leiningen's built-in test task, you can tag tests with metadata that allows you to run just a selection of your tests.

You can put a keyword argument on the command-line invocation before specifying which test namespaces to run, and it will cause all deftest forms which aren't tagged with that metadata to be skipped.

$ lein run -m circleci.test :integration my.first.test.ns

If you need more flexibility in your test selectors you can define arbitrary selector functions in dev-resources/circleci_test/config.clj:

{:selectors {:all (constantly true)
             :acceptance (fn [m] (or (:integration m) (:functional m)))
             :default (complement :flaky)}}

If you have the Leiningen :aliases set up as per above, you can pass in a test selector as a command-line argument:

$ lein test :acceptance

Reporters

JUnit

In order to gather metadata about your test runs, you can configure circleci.test to emit output in JUnit XML format by putting this in your dev-resources/circleci_test/config.clj file:

(require '[circleci.test.report.junit :as junit])

{:test-results-dir "target/test-results"
 :reporters [circleci.test.report/clojure-test-reporter
             junit/reporter]}

Unlike clojure.test, you can use more than one reporter at a time. It's recommended to add your :test-results-dir directory to the ignored list of your version control system.

If you use the junit test reporter, you can run circleci.test.retest/-main to re-run only the set of tests which previously failed. Adding an alias in project.clj is recommended:

:aliases {"test" ["run" "-m" "circleci.test/dir" :project/test-paths]
          "retest" ["run" "-m" "circleci.test.retest"]}

CIDER

circleci.test by default breaks CIDER test reports. To avoid this, use these settings in your dev-resources/circleci_test/config.clj to activate the CIDER test result adapter:

(require '[circleci.test.report.cider :as cider])

{:reporters [circleci.test.report/clojure-test-reporter
             cider/reporter]}

Running tests from a repl

Use circleci.test/test-var to run a single test fn:

(circleci.test/test-var #'my.test.ns/my-test)

Use circleci.test/run-tests to run all the tests in one or more namespaces:

(circleci.test/run-tests 'my.test.ns)
(circleci.test/run-tests 'my.test.ns 'my.other.test.ns)

There is also a circleci.test/run-all-tests function; however please note that this only runs tests in namespaces that have already been loaded rather than running all tests that exist on disk.

Global fixtures

In addition to :once and :each fixtures from clojure.test, you can define global fixtures that are only run once for the entire test run, no matter how many namespaces you run. This should be declared in your config file rather in any one individual test file though; otherwise it may not get loaded:

(require '[clojure.spec.test.alpha :as stest])
{:global-fixture (fn [f]
                   (stest/instrument)
                   (myapp.db/migrate)
                   (f))}

The global fixture must return the return value of f. If you need to do a teardown step you must do something like this:

(require '[clojure.spec.test.alpha :as stest])
{:global-fixture (fn [f]
                   (stest/instrument)
                   (myapp.db/migrate)
                   (let [results (f)]
                     (teardown)
                     results))}

Test Isolation

Clojure codebases that follow functional programming techniques should follow the "functional core/imperative shell" model in which most functionality is implemented with pure functions, while an outer layer of imperative code ties things together. Ideally in this case most tests should be unit tests, which only concern themselves with pure functions and do no I/O. However, it's easy for impurity to accidentally sneak into a test. In order to prevent this, you can use the circleci.test.isolation/enforce test fixture.

(use-fixtures :each (isolation/enforce))

(deftest accidentally-uses-io
  (is (re-find #"cx") (get-in (read-parse "sample3") [:body :content 3])))

(def sample3 (read-sample "sample3"))

(deftest actually-pure
  (is (re-find #"cx") (get-in (parse sample3) [:body :content 3])))

(deftest ^:io intentionally-uses-io
  (let [sample3 (read-sample "sample3")
        parsed (parse sample3)]
    (is (re-find #"cx") (get-in parsed [:body :content 3]))))

The first test is not a unit test because it calls read-parse, a function that performs I/O. The isolation/enforce fixture will cause it to fail, while the second one will succeed because it only calls parse, which is pure. The third test will also pass because it has explicitly been flagged with ^:io.

The default isolation blocks use of network and file access and whitelists deftests which are tagged with ^:io and ^:integration. You can pass arguments to isolation/enforce which will provide a fixture that looks for different set of selector tags or uses a different predicate to determine which things to block:

(defn deny? [permission]
  (instance? java.net.SocketPermission permission))

(use-fixtures :each (isolation/enforce [:io :network] deny?))

In this example we only block tests which use SocketPermission. The deny? predicate will be passed an instance of java.security.Permission and must return a boolean indicating whether that permission should be denied. In this case only deftest forms with ^:io or ^:network selector tags will not have that restriction applied.

This feature sets the JVM's SecurityManager for the duration of each test, and will not work when testing code that sets or otherwise assumes it has control of the system SecurityManager.

Differences from clojure.test

• supports more than one test reporter at a time
• includes elapsed time measured with System/nanoTime when reporting the end of a deftest
• test fixtures are run when testing a single test, not just a set of tests
• :once fixtures are run exactly once per invocation, whether testing an entire namespace or a single test
• test selectors are a part of the library, not a monkeypatch

Caveats

• Invoking a test-fn directly will not run any fixtures at all, exactly like clojure.test. This is due to behaviour from clojure.test/deftest and can't be worked around without forcing use of a different deftest implementation.

Code Coverage support

You can get code coverage support while using this library by using version 1.0.10 or higher of Cloverage specifying circleci.test as your test runner, like so:

lein cloverage --runner circleci.test

Design goals

Compatibility with tests written using clojure.test

Don't force people to re-write tests just to use a different test runner.

Maintain compatibility with the clojure.test assertion expansions such as slingshot.test

Extensible test reporting

Must be possible to use more than one test reporter at a time, for instance it's desirable to produce Junit XML and console output during a test run.

License

Copyright © 2017-2020 Circle Internet Services and contributors

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.