+(test-assert "dmd-service-back-edges"
+ (let* ((s1 (dmd-service (provision '(s1)) (start #f)))
+ (s2 (dmd-service (provision '(s2)) (requirement '(s1)) (start #f)))
+ (s3 (dmd-service (provision '(s3)) (requirement '(s1 s2)) (start #f)))
+ (e (dmd-service-back-edges (list s1 s2 s3))))
+ (and (lset= eq? (e s1) (list s2 s3))
+ (lset= eq? (e s2) (list s3))
+ (null? (e s3)))))
+