Testeez: Lightweight Unit Test Mechanism for R5RS Scheme

Version 0.3, 2005-05-30, http://www.neilvandyke.org/testeez/

by Neil W. Van Dyke <neil@neilvandyke.org>

Copyright © 2005 Neil W. Van Dyke. This program is Free Software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See <http://www.gnu.org/copyleft/lesser.html> for details. For other license options and consulting, contact the author.

Introduction

Testeez is a simple lightweight unit test mechanism for R5RS Scheme. It was written to support regression test suites embedded within the source code files of the author's portable Scheme libraries.

A series of Testeez tests is listed within the testeez syntax. By following a simple convention, these tests can be disabled and the dependency on Testeez removed for production code. For example, to use Testeez in a “Foo” library, one can first add a syntax wrapper around testeez like so: 

     (define-syntax %foo:testeez
       (syntax-rules ()
         ((_ X ...)
          ;; Note: Comment-out exactly one of the following two lines.
          ;; (error "Tests disabled.")
          (testeez X ...)
          )))

Then, this wrapper %foo:testeez can be used in a procedure that executes the test suite of the “Foo” library: 

     (define (%foo:test)
       (%foo:testeez
        "Foo Station"
     
        (test/equal "Put two and two together" (+ 2 2) 4)
     
        (test-define "Bar function" bar (lambda (x) (+ x 42)))
     
        (test/equal "Bar scene" (bar 69) 0)
     
        (test/eqv   "Full circle" (* (bar -21) 2) 42)
     
        (test/eqv   "Multiple"
                    (values (+ 2 2) (string #\h #\i) (char-upcase #\p))
                    (values 4 "hi" #\P))))

When the tests are enabled and (%foo:test) is evaluated, output like the following (which looks prettier fontified in Emacs's *scheme* buffer) is printed: 

     ;;; BEGIN "Foo Station" TESTS
     
     ;; 1. Put two and two together
     (+ 2 2)
     ;; ==> 4
     ;; Passed.
     
     ;; DEFINE: Bar function
     (define bar (lambda (x) (+ x 42)))
     
     ;; 2. Bar scene
     (bar 69)
     ;; ==> 111
     ;; FAILED!  Expected:
     ;;     0
     
     ;; 3. Full circle
     (* (bar -21) 2)
     ;; ==> 42
     ;; Passed.
     
     ;; 4. Multiple
     (values (+ 2 2) (string #\h #\i) (char-upcase #\p))
     ;; ==> 4
     ;;     "hi"
     ;;     #\P
     ;; Passed.
     
     ;;; END "Foo Station" TESTS: FAILED
     ;;;     (Total: 4  Passed: 3  Failed: 1)

The testeez syntax also supports shorthand or abbreviated forms, for quick interactive use, such as in an editor buffer while rapid-prototyping a function, and in a REPL while debugging. For an example of shorthand, the Scheme expression: 

     (testeez ((+ 1 2) 3) ((* 6 7) 42))

is equivalent to: 

     (testeez ""
              (test/equal "" (+ 1 2) 3)
              (test/equal "" (* 6 7) 42))

Future versions of Testeez will add additional features, such as custom predicates and handling of errors.

Interface

The interface consists of the testeez syntax.

— Syntax: testeez [ title ] form ...

The testeez syntax contains a short string title and one or more forms, of the following syntaxes, which are evaluated in order.

(test/equal desc expr expected)
Execute a test case. desc is a short title or description of the test case, expr is a Scheme expression, and expected is an expression for the expected value (or multiple values). The test case passes iff each value of expr is equal? to the corresponding value of expected.
(test/eq desc expr expected)
Like test/equal, except the equivalence predicate is eq? rather than equal?.
(test/eqv desc expr expected)
Like test/equal, except the equivalence predicate is eqv? rather than equal?.
(test-define desc name val)
Bind a variable. desc is a short description string, name is the identifier, and val is the value expression. The binding is visible to the remainder of the enclosing testeez syntax.
(test-eval desc expr)
Evaluate an expression.
(expr expected)
Shorthand for (test/equal "" expr expected). This shorthand is intended for interactive and rapid-prototyping use, not for released code.

History

Version 0.3 — 2005-05-30
Shorthand syntax added. Minor formatting change to test log output.
Version 0.2 — 2005-03-07
Multiple values are now supported. test/eq and test/eqv have been added. Minor formatting changes to test log output.
Version 0.1 — 2005-01-02
Initial release.