scmunit – Unit testing for Scheme with ease

scmunit is a simple and lightweight test runner plus assertion library written in and for MIT Scheme (R7RS). scmunit comes with the following features:

• 🚀 Small footprint (100 lines of code, 4 kB)
• 🐣 Dead simple API (4 functions – that’s all there is)
• 📝 Concise yet helpful report
• ⏱ Runtime measurements

Example

(load "scmunit.scm")

(define (increment x) (+ x 1))

(testcase* "increments numbers by 1" (list
    (assert eq? (increment 0) 1)
    (assert eq? (increment 12) 13)
))

(scmunit-run*)

Also, see another demonstration in test/example.scm.

Reference

(assert predicate expression [arguments])

Evaluates an expression against a predicate. The assertion is considered to be successful if the predicate returns true (#t).

• predicate A predicate that takes the result of expression as first argument and arguments as subsequent arguments
• expression The expression that you want to test
• arguments See predicate

(testcase name [items])

Container for grouping assertions and/or other testcases. Can be nested arbitrarily deep.

• name a string for recognising the testcase in the test output of the runner
• items a list of assertions and/or testcases

(testcase* ...)

Same as (testcase ...), but it automatically registers the testcases with all its content, so that it gets picked up by the test runner. Supposed to be used at top-level.

(scmunit-run*)

Runs all testcases that had been registered via (testcase* ...), displays the result and exits the program with status 0 or 1 (depending on whether there were failed tests or not).

FAQ

How can I declare local variables or functions in a testcase?

Provide the list of test items by means of a let block:

(testcase "magic computation" (let ((MAGIC 42))
    (define (square x) (* x x))
    (list
        (assert eq? (square MAGIC) 1764)
)))

Can test testcases be nested?

Yes, arbitrarily deep:

(testcase "foo" (list
    (testcase "bar" (list
        (testcase "baz" (list
            ; ...
        ))
    ))
))