3
5
Fork 0
mirror of git://git.savannah.gnu.org/guix.git synced 2023-12-14 03:33:07 +01:00
guix/tests/monads.scm
Ludovic Courtès dbbc248aee monads: Fix 'liftN' fallback case.
Reported by Andy Wingo <wingo@igalia.com>.

* guix/monads.scm (define-lift) <fallback case>: Add missing #'.  Remove
  extra formal parameter.
* tests/monads.scm ("lift"): Add test with 'lift1' as a procedure.
2015-09-04 18:31:06 +02:00

259 lines
8.8 KiB
Scheme
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix 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 the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (test-monads)
#:use-module (guix tests)
#:use-module (guix store)
#:use-module (guix monads)
#:use-module (guix derivations)
#:use-module (guix packages)
#:use-module (gnu packages)
#:use-module (gnu packages bootstrap)
#:use-module ((gnu packages base) #:select (coreutils))
#:use-module (ice-9 match)
#:use-module (rnrs io ports)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:use-module (srfi srfi-64))
;; Test the (guix monads) module.
(define %store
(open-connection-for-tests))
(define %monads
(list %identity-monad %store-monad %state-monad))
(define %monad-run
(list identity
(cut run-with-store %store <>)
(cut run-with-state <> '())))
(define-syntax-rule (values->list exp)
(call-with-values (lambda () exp)
list))
(test-begin "monads")
(test-assert "monad?"
(and (every monad? %monads)
(every (compose procedure? monad-bind) %monads)
(every (compose procedure? monad-return) %monads)))
;; The 3 "monad laws": <http://www.haskell.org/haskellwiki/Monad_laws>.
(test-assert "left identity"
(every (lambda (monad run)
(let ((number (random 777)))
(with-monad monad
(define (f x)
(return (* (1+ number) 2)))
(= (run (>>= (return number) f))
(run (f number))))))
%monads
%monad-run))
(test-assert "right identity"
(every (lambda (monad run)
(with-monad monad
(let ((number (return (random 777))))
(= (run (>>= number return))
(run number)))))
%monads
%monad-run))
(test-assert "associativity"
(every (lambda (monad run)
(with-monad monad
(define (f x)
(return (+ 1 x)))
(define (g x)
(return (* 2 x)))
(let ((number (return (random 777))))
(= (run (>>= (>>= number f) g))
(run (>>= number (lambda (x) (>>= (f x) g))))))))
%monads
%monad-run))
(test-assert "lift"
(every (lambda (monad run)
(let ((f (lift1 1+ monad))
(g (apply lift1 1+ (list monad))))
(with-monad monad
(let ((number (random 777)))
(= (run (>>= (return number) f))
(run (>>= (return number) g))
(1+ number))))))
%monads
%monad-run))
(test-assert ">>= with more than two arguments"
(every (lambda (monad run)
(let ((1+ (lift1 1+ monad))
(2* (lift1 (cut * 2 <>) monad)))
(with-monad monad
(let ((number (random 777)))
(= (run (>>= (return number)
1+ 1+ 1+
2* 2* 2*))
(* 8 (+ number 3)))))))
%monads
%monad-run))
(test-assert "mbegin"
(every (lambda (monad run)
(with-monad monad
(let* ((been-there? #f)
(number (mbegin monad
(return 1)
(begin
(set! been-there? #t)
(return 2))
(return 3))))
(and (= (run number) 3)
been-there?))))
%monads
%monad-run))
(test-assert "mlet* + text-file + package-file"
(run-with-store %store
(mlet* %store-monad ((guile (package-file %bootstrap-guile "bin/guile"))
(file (text-file "monadic" guile)))
(return (equal? (call-with-input-file file get-string-all)
guile)))
#:guile-for-build (package-derivation %store %bootstrap-guile)))
(test-assert "package-file, default system"
;; The default system should be the one at '>>=' time, not the one at
;; invocation time. See <http://bugs.gnu.org/18002>.
(run-with-store %store
(mlet* %store-monad
((system -> (%current-system))
(file (parameterize ((%current-system "foobar64-linux"))
(package-file coreutils "bin/ls")))
(cu (package->derivation coreutils)))
(return (string=? file
(string-append (derivation->output-path cu)
"/bin/ls"))))
#:guile-for-build (package-derivation %store %bootstrap-guile)))
(test-assert "package-file + package->cross-derivation"
(run-with-store %store
(mlet* %store-monad ((target -> "mips64el-linux-gnu")
(file (package-file coreutils "bin/ls"
#:target target))
(xcu (package->cross-derivation coreutils target)))
(let ((output (derivation->output-path xcu)))
(return (string=? file (string-append output "/bin/ls")))))
#:guile-for-build (package-derivation %store %bootstrap-guile)))
(test-assert "interned-file"
(run-with-store %store
(mlet* %store-monad ((file -> (search-path %load-path "guix.scm"))
(a (interned-file file))
(b (interned-file file "b")))
(return (equal? (call-with-input-file file get-string-all)
(call-with-input-file a get-string-all)
(call-with-input-file b get-string-all))))
#:guile-for-build (package-derivation %store %bootstrap-guile)))
(test-assert "mapm"
(every (lambda (monad run)
(with-monad monad
(equal? (run (mapm monad (lift1 1+ monad) (iota 10)))
(map 1+ (iota 10)))))
%monads
%monad-run))
(test-assert "sequence"
(every (lambda (monad run)
(let* ((input (iota 100))
(order '()))
(define (frob i)
(mlet monad ((foo (return 'foo)))
;; The side effect here is used to keep track of the order in
;; which monadic values are bound. Perform the side effect
;; within a '>>=' so that it is performed when the return
;; value is actually bound.
(set! order (cons i order))
(return i)))
(and (equal? input
(run (sequence monad (map frob input))))
;; Make sure this is from left to right.
(equal? order (reverse input)))))
%monads
%monad-run))
(test-assert "listm"
(every (lambda (monad run)
(run (with-monad monad
(let ((lst (listm monad
(return 1) (return 2) (return 3))))
(mlet monad ((lst lst))
(return (equal? '(1 2 3) lst)))))))
%monads
%monad-run))
(test-assert "anym"
(every (lambda (monad run)
(eq? (run (with-monad monad
(anym monad
(lift1 (lambda (x)
(and (odd? x) 'odd!))
monad)
(append (make-list 1000 0)
(list 1 2)))))
'odd!))
%monads
%monad-run))
(test-equal "set-current-state"
(list '(a a d) 'd)
(values->list
(run-with-state
(mlet* %state-monad ((init (current-state))
(init2 (set-current-state 'b)))
(mbegin %state-monad
(set-current-state 'c)
(set-current-state 'd)
(mlet %state-monad ((last (current-state)))
(return (list init init2 last)))))
'a)))
(test-equal "state-push etc."
(list '((z . 2) (p . (1)) (a . (1))) '(2 1))
(values->list
(run-with-state
(mbegin %state-monad
(state-push 1) ;(1)
(state-push 2) ;(2 1)
(mlet* %state-monad ((z (state-pop)) ;(1)
(p (current-state))
(a (state-push z))) ;(2 1)
(return `((z . ,z) (p . ,p) (a . ,a)))))
'())))
(test-end "monads")
(exit (= (test-runner-fail-count (test-runner-current)) 0))