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Test with a little caffeine.

Tespresso is a collection of clojure.test helpers.

Releases and Dependency Information

Releases are on Clojars.

Clojure CLI/deps.edn coordinates:

{com.grzm/tespresso.alpha {:mvn/version "0.1.11"}}

Leiningen/Boot dependency information:

[com.grzm/tespresso.alpha "0.1.11"]

Maven dependency information:



Clojure Spec helpers

Tespresso provides a defcheck macro for testing as well as a check? assert-expr to exercise individual specs.

(ns com.example.spec-test
   [clojure.spec.alpha :as s]
   [clojure.spec.test.alpha :as stest]
   [clojure.test :refer [deftest is]]
   [com.grzm.tespresso.spec.alpha :refer [defcheck]))

(def stc-opts-key #?(:clj :clojure.spec.test.check/opts
                     :cljs :cljs.spec.test.check/opts))

(defn adder [a b]
  (+ a b))

(s/fdef adder
        :args (s/cat :a int? :b int?)
        :ret int?)

(deftest check-adder
  (is (com.grzm.tespresso.spec/check?
        (stest/check `adder {stc-opts-key {:num-tests 100}}))))

The defcheck macro provides a convenient shorthand for this simple case.

(defcheck spec-test-adder `adder)

defcheck is currently Clojure only.

Test ex-data

Clojure's ex-info is great. Confirm you're getting back what you expect when an exception is thrown.

(ns com.example.thrown-test
   [clojure.test :refer [deftest is]]
   [com.grzm.tespresso.alpha :as tespresso]))

(deftest has-expected-ex-data
  (is (com.grzm.tespresso/thrown-with-data?
        #(= ::self-inflicted (:cause %))
        (throw (ex-info "yeah, I'm gonna throw"
                        {:cause ::self-inflicted,
                         :a-key :a-value
                         :another-key :another-value})))))

Helper functions tespresso/ex-data= and tespresso/ex-data-select= provide convenient short-hands for matching all or partial key-values in ex-data.

;; match all keys and values
(deftest has-expected-ex-data-full-match
  (is (com.grzm.tespresso/thrown-with-data?
        (tespresso/ex-data= {:cause ::self-inflicted,
                             :a-key :a-value,
                             :another-key :another-value})
        (throw (ex-info "Still throwin'"
                        {:cause ::self-inflicted,
                         :a-key :a-value
                         :another-key :another-value})))))

;; match just the key-vals provided
(deftest has-expected-ex-data-select-match
  (is (com.grzm.tespresso/thrown-with-data?
        (tespresso/ex-data-select= {:cause ::self-inflicted,
                                    :a-key :a-value})
        (throw (ex-info "Can't stop me now!"
                        {:cause ::self-inflicted,
                         :a-key :a-value
                         :another-key :another-value})))))

An optional regex can be passed to also match the message.

;; match just the key-vals provided
(deftest has-expected-ex-data-select-match
  (is (com.grzm.tespresso/thrown-with-data?
        #"^Can't stop"
        (tespresso/ex-data-select= {:cause ::self-inflicted,
                                    :a-key :a-value})
        (throw (ex-info "Can't stop me now!"
                        {:cause ::self-inflicted,
                         :a-key :a-value
                         :another-key :another-value})))))

Test Component systems

The with-system and with-system-options macros help testing systems built with Stuart Sierra's component library.

The with-system macro takes an initial value of a system, starts it, and makes it available as the value of an atom. After evaluating the body, the system is stopped.

  '[com.grzm.tespresso.component.alpha :refer [with-system])

(with-system [sys init-sys-value]
   ;; access system value by deferencing `sys` atom
   (is (= [:app :db] (keys @sys))))


Sometimes you might want to confirm logging is working as expected. Test using the with-logging macro to capture log output. Available for Clojure only.

   [clojure.test :refer [deftest is]]
   [ :as log]
   [ :refer [with-logging]]))

(deftest test-logging
  (with-logging [#{:info :warn} log-entries]
    (log/tracef "Some trace message")
    (log/infof "Some info message")
    (log/warnf "Some example warning")
    (is (= [["" :info nil "Some info message"]
            ["" :warn nil "Some example warning"]]

Compare bytes

In Clojure, com.grzm.tespresso.bytes relies on Zach Tellman's byte-streams library.

(ns com.example.bytes-test
   [clojure.test :refer [deftest is]]
   [com.grzm.tespresso.alpha :as tespresso :refer [capture-test-var]]
   [com.grzm.tespresso.bytes.alpha :as bytes]))

(deftest byte-inequality-example
  (is (com.grzm.tespresso.bytes/bytes=
        (bytes/byte-buffer [0 1 (int \a) 3])
        (bytes/byte-buffer [0 2 4 3]))))

Test clojure.test?

When developing new assertions and test macros, it's helpful to actually test the test output, particularly when you want to confirm a failing test reports correctly. Relying on visual inspection of test run output is problematic, not only because you might miss details, but also because a test that's failing unexpectedly may get lost in the expected failing output.

(ns com.example.test-test-output
   [clojure.test :refer [deftest is]]
   [com.grzm.tespresso.alpha :as tespresso :refer [capture-test-var]))

(deftest ^::capture test-to-capture
  (is (= 1 2)))

(deftest test-capture
  (let [{:keys [test-out] :as capture} (capture-test-var #'test-to-capture)]
    ;; com.grzm.tespresso/lines-match? takes an sequence of
    ;; regex patterns or strings to match against the output
    (is (com.grzm.tespresso/lines-match?
          [#"FAIL in \(test-to-capture\)"
           "expected: (= 1 2)"
           "  actual: (not (= 1 2))"]

;; implement test-ns-hook to ignore marked tests during a test run
(defn test-ns-hook
    (ns-interns 'com.example.test-test-output) ::capture))

capture-test-var returns a map of :test-out, :out, :report-counters, and :reports.

Note that while test-ns-hook is supported by clojure.test (and cljs.test), not all test runners support test-ns-hook. The test-ns-interns-sans-meta-key

Tespresso eats its own dog food

For more examples of Tespresso in action, take a look at Tespresso's own tests.

Testing Tespresso

Testing Clojure implementation

lein test

Testing JVM ClojureScript implementation

lein clean && lein cljsbuild once

Testing self-hosted ClojureScript implementation


Not all functionality is tested under self-hosted environments.


© 2017-2018 Michael Glaesemann

Released under the MIT License. See LICENSE for details.