quick-check

Tests `property` `num-tests` times. Takes several optional keys: `:seed` Can be used to re-run previous tests, as the seed used is returned after a test is run. `:max-size`. can be used to control the 'size' of generated values. The size will start at 0, and grow up to max-size, as the number of tests increases. Generators will use the size parameter to bound their growth. This prevents, for example, generating a five-thousand element vector on the very first test. `:reporter-fn` A callback function that will be called at various points in the test run, with a map like: ;; called after a passing trial {:type :trial :args [...] :num-tests <number of tests run so far> :num-tests-total <total number of tests to be run> :seed 42 :pass? true :property #<...> :result true :result-data {...}} ;; called after the first failing trial {:type :failure :fail [...failing args...] :failing-size 13 :num-tests <tests ran before failure found> :pass? false :property #<...> :result false/exception :result-data {...} :seed 42} It will also be called on :complete, :shrink-step and :shrunk. Many of the keys also appear in the quick-check return value, and are documented below. If the test passes, the return value will be something like: {:num-tests 100, :pass? true, :result true, :seed 1561826505982, :time-elapsed-ms 24} If the test fails, the return value will be something like: {:fail [0], :failed-after-ms 0, :failing-size 0, :num-tests 1, :pass? false, :result false, :result-data nil, :seed 1561826506080, :shrunk {:depth 0, :pass? false, :result false, :result-data nil, :smallest [0], :time-shrinking-ms 0, :total-nodes-visited 0}} The meaning of the individual entries is: :num-tests The total number of trials that was were run, not including shrinking (if applicable) :pass? A boolean indicating whether the test passed or failed :result A legacy entry that is similar to :pass? :seed The seed used for the entire test run; can be used to reproduce a test run by passing it as the :seed option to quick-check :time-elapsed-ms The total time, in milliseconds, of a successful test run :fail The generated values for the first failure; note that this is always a vector, since prop/for-all can have multiple clauses :failed-after-ms The total time, in milliseconds, spent finding the first failing trial :failing-size The value of the size parameter used to generate the first failure :result-data The result data, if any, of the first failing trial (to take advantage of this a property must return an object satisfying the clojure.test.check.results/Result protocol) :shrunk A map of data about the shrinking process; nested keys that appear at the top level have the same meaning; other keys are documented next :shrunk / :depth The depth in the shrink tree that the smallest failing instance was found; this is essentially the idea of how many times the original failure was successfully shrunk :smallest The smallest values found in the shrinking process that still fail the test; this is a vector of the same type as :fail :time-shrinking-ms The total time, in milliseconds, spent shrinking :total-nodes-visited The total number of steps in the shrinking process Examples: (def p (for-all [a gen/nat] (> (* a a) a))) (quick-check 100 p) (quick-check 200 p :seed 42 :max-size 50 :reporter-fn (fn [m] (when (= :failure (:type m)) (println "Uh oh..."))))