Adds foo test with minimal assertion library.

scheme/assert.scm

@@ -0,0 +1,58 @@
+;;;
+;;; Unit test framework for Scheme
+;;; Copyright (c) 2018, Peter Kofler, http://www.code-cop.org/
+;;; BSD licensed.
+;;;
+;;; Non S5RS used functions:
+;;; * (error) from R6RS
+;;;
+
+;; SchemeUnit from http://c2.com/cgi/wiki?SchemeUnit
+
+(define (fail msg)
+    (error (string-append "AssertionError" ": " msg)))
+
+(define (check msg condition)
+    (if (not condition)
+        (fail msg)
+        #t))
+
+(define (assert msg condition)
+    (lambda () (check msg condition)))
+
+;; extensions
+
+;; private
+(define (make-string-message prefix to-string expected actual)
+    (make-message prefix
+                  (to-string expected)
+                  (to-string actual)))
+
+;; private
+(define (make-message prefix expected actual)
+    (string-append prefix "expected:<" expected "> but was:<" actual ">"))
+
+(define (assert-equal to-string eq-op expected actual)
+    (assert (make-string-message "" to-string expected actual)
+            (eq-op expected actual)))
+
+(define (assert= expected actual)
+    (assert-equal number->string = expected actual))
+
+(define (assert-string= expected actual)
+    (assert-equal values string=? expected actual))
+
+;; private
+(define (test-case-name name)
+    (display name)
+    (display " ... "))
+
+;; private
+(define (test-case-success)
+    (display "OK")
+    (newline))
+
+(define (test-case name . assertions)
+    (test-case-name name)
+    (for-each (lambda (a) (a)) assertions)
+    (test-case-success))

scheme/gilded-rose-test.scm

@@ -0,0 +1,7 @@
+(include "assert.scm")
+(include "gilded-rose.scm")
+
+(test-case "foo"
+    (let ((items (list (make-item "foo" 0 0))))
+        (update-quality items)
+        (assert-string= "fixme" (item-name (car items)))))