tests: Add 'with-environment-variable'.

* tests/scripts.scm (with-environment-variable): Move to...
* guix/tests.scm (with-environment-variable): ... here.
* tests/build-utils.scm ("wrap-program, one input, multiple calls"):
Use it instead of 'setenv'.

guix/tests.scm

@@ -39,6 +39,8 @@ (define-module (guix tests)
             canonical-file?
             network-reachable?
             shebang-too-long?
+            with-environment-variable
+
             mock
             %test-substitute-urls
             test-assertm
@@ -195,6 +197,19 @@ (define-syntax-rule (test-equalm name value exp)
       (run-with-store store exp
                       #:guile-for-build (%guile-for-build)))))
 
+(define-syntax-rule (with-environment-variable variable value body ...)
+  "Run BODY with VARIABLE set to VALUE."
+  (let ((orig (getenv variable)))
+    (dynamic-wind
+      (lambda ()
+        (setenv variable value))
+      (lambda ()
+        body ...)
+      (lambda ()
+        (if orig
+            (setenv variable orig)
+            (unsetenv variable))))))
+
 
 ;;;
 ;;; Narinfo files, as used by the substituter.

tests/build-utils.scm

@@ -107,12 +107,13 @@ (define-module (test-build-utils)
        ;; it can't know about the bootstrap bash in the store, since it's not
        ;; named "bash".  Help it out a bit by providing a symlink it this
        ;; package's output.
-       (setenv "PATH" (dirname bash))
+       (with-environment-variable "PATH" (dirname bash)
          (wrap-program foo `("GUIX_FOO" prefix ("hello")))
          (wrap-program foo `("GUIX_BAR" prefix ("world")))
 
-       ;; The bootstrap Bash is linked against an old libc and would abort with
-       ;; an assertion failure when trying to load incompatible locale data.
+         ;; The bootstrap Bash is linked against an old libc and would abort
+         ;; with an assertion failure when trying to load incompatible locale
+         ;; data.
          (unsetenv "LOCPATH")
 
          (let* ((pipe (open-input-pipe foo))
@@ -120,6 +121,7 @@ (define-module (test-build-utils)
            (with-directory-excursion directory
              (for-each delete-file '("foo" ".foo-real")))
            (and (zero? (close-pipe pipe))
-              str))))))
+                str)))))))
+
 
 (test-end)

tests/scripts.scm

@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2015 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2015, 2019 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -25,19 +25,6 @@ (define-module (test-scripts)
 
 ;; Test the (guix scripts) module.
 
-(define-syntax-rule (with-environment-variable variable value body ...)
-  "Run BODY with VARIABLE set to VALUE."
-  (let ((orig (getenv variable)))
-    (dynamic-wind
-      (lambda ()
-        (setenv variable value))
-      (lambda ()
-        body ...)
-      (lambda ()
-        (if orig
-            (setenv variable orig)
-            (unsetenv variable))))))
-
 
 (test-begin "scripts")