services: Export 'service-back-edges'.

* gnu/services.scm: Export 'service-back-edges' and <service-type>
  accessors.
* tests/services.scm ("service-back-edges"): New test.
This commit is contained in:
Ludovic Courtès 2015-10-14 14:58:25 +02:00
parent 87cd0dba2f
commit 5152d13b51
2 changed files with 24 additions and 0 deletions

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@ -38,12 +38,17 @@
service-type
service-type?
service-type-name
service-type-extensions
service-type-compose
service-type-extend
service
service?
service-kind
service-parameters
service-back-edges
fold-services
service-error?

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@ -25,6 +25,25 @@
(test-begin "services")
(test-assert "service-back-edges"
(let* ((t1 (service-type (name 't1) (extensions '())
(compose +) (extend *)))
(t2 (service-type (name 't2)
(extensions
(list (service-extension t1 (const '()))))
(compose +) (extend *)))
(t3 (service-type (name 't3)
(extensions
(list (service-extension t2 identity)
(service-extension t1 list)))))
(s1 (service t1 #t))
(s2 (service t2 #t))
(s3 (service t3 #t))
(e (service-back-edges (list s1 s2 s3))))
(and (lset= eq? (e s1) (list s2 s3))
(lset= eq? (e s2) (list s3))
(null? (e s3)))))
(test-equal "fold-services"
;; Make sure 'fold-services' returns the right result. The numbers come
;; from services of type T3; 'xyz 60' comes from the service of type T2,