--- srfi-19.test.~1.1.~	Sat Jun 16 16:11:39 2001
+++ srfi-19.test	Mon Aug 20 22:34:10 2001
@@ -80,6 +80,14 @@
 	      (let ((time (make-time ,a 12345 67890123)))
 		(time=? time (,b->a-sym (,a->b-sym time)))))))
 
+(define (test-time-comparison cmp a b)
+  (pass-if (format #f "~A works" cmp)
+           (cmp a b)))
+
+(define (test-time-arithmetic op a b res)
+  (pass-if (format #f "~A works" op)
+           (time=? (op a b) res)))
+
 (with-test-prefix "SRFI date/time library"
   ;; check for typos and silly errors
   (pass-if "date-zone-offset is defined"
@@ -126,7 +134,23 @@
 		    (with-tz "CET"
 		      (string->date "address@hidden:00" "address@hidden:~M")))
 		   (date->time-utc
-		    (make-date 0 0 0 12 1 6 2001 0)))))
+		    (make-date 0 0 0 12 1 6 2001 0))))
+  ;; check time comparison procedures
+  (let* ((time1 (make-time time-monotonic 0 0))
+         (time2 (make-time time-monotonic 0 0))
+         (time3 (make-time time-monotonic 385907 998360432))
+         (time4 (make-time time-monotonic 385907 998360432)))
+    (test-time-comparison time<=? time1 time3)
+    (test-time-comparison time<?  time1 time3)
+    (test-time-comparison time=?  time1 time2)
+    (test-time-comparison time>=? time3 time3)
+    (test-time-comparison time>?  time3 time2))
+  ;; check time arithmetic procedures
+  (let* ((time1 (make-time time-monotonic 0 0))
+         (time2 (make-time time-monotonic 385907 998360432))
+         (diff (time-difference time2 time1)))
+    (test-time-arithmetic add-duration time1 diff time2)
+    (test-time-arithmetic subtract-duration time2 diff time1)))
 
 ;; Local Variables:
 ;; eval: (put 'with-tz 'scheme-indent-function 1)