From dac1c97d131d297134fa878ac240d9ec0127044b Mon Sep 17 00:00:00 2001
From: Ludovic Courtès <ludo@gnu.org>
Date: Sat, 28 Apr 2018 17:17:33 +0200
Subject: union: Add 'relative-file-name'.

* guix/build/union.scm (%not-slash): New variable.
(relative-file-name): New procedure.
* tests/union.scm (test-relative-file-name): New macro and tests.
---
 tests/union.scm | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

(limited to 'tests/union.scm')

diff --git a/tests/union.scm b/tests/union.scm
index aa95cae001..5a6a4033fc 100644
--- a/tests/union.scm
+++ b/tests/union.scm
@@ -184,4 +184,22 @@
                 (file-is-directory? "bin")
                 (eq? 'symlink (stat:type (lstat "bin/guile"))))))))
 
+(letrec-syntax ((test-relative-file-name
+                 (syntax-rules (=>)
+                   ((_ (reference file => expected) rest ...)
+                    (begin
+                      (test-equal (string-append "relative-file-name "
+                                                 reference " " file)
+                        expected
+                        (relative-file-name reference file))
+                      (test-relative-file-name rest ...)))
+                   ((_)
+                    #t))))
+  (test-relative-file-name
+   ("/a/b" "/a/c/d"     => "../c/d")
+   ("/a/b" "/a/b"       => "")
+   ("/a/b" "/a"         => "..")
+   ("/a/b" "/a/b/c/d"   => "c/d")
+   ("/a/b/c" "/a/d/e/f" => "../../d/e/f")))
+
 (test-end)
-- 
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