Add (guix build union).

* guix/build/union.scm, tests/union.scm: New files.
* Makefile.am (MODULES): Add `guix/build/union.scm'.
  (TESTS): Add `tests/union.scm'.

tests/union.scm

@@ -0,0 +1,103 @@
+;;; Guix --- Nix package management from Guile.         -*- coding: utf-8 -*-
+;;; Copyright (C) 2012 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of Guix.
+;;;
+;;; 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.
+;;;
+;;; 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 Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+
+(define-module (test-union)
+  #:use-module (guix store)
+  #:use-module (guix utils)
+  #:use-module (guix derivations)
+  #:use-module (guix packages)
+  #:use-module (guix build union)
+  #:use-module ((guix build utils)
+                #:select (with-directory-excursion directory-exists?))
+  #:use-module (srfi srfi-64)
+  #:use-module (ice-9 match))
+
+;; Exercise the (guix build union) module.
+
+(define %store
+  (false-if-exception (open-connection)))
+
+(define %bootstrap-guile
+  (@@ (distro packages base) %bootstrap-guile))
+
+(when %store
+  ;; By default, use %BOOTSTRAP-GUILE for the current system.
+  (let ((drv (package-derivation %store %bootstrap-guile)))
+    (%guile-for-build drv)))
+
+
+(test-begin "union")
+
+(test-equal "tree-union, empty"
+  '()
+  (tree-union '()))
+
+(test-equal "tree-union, leaves only"
+  '(a b c d)
+  (tree-union '(a b c d)))
+
+(test-equal "tree-union, simple"
+  '((bin ls touch make awk gawk))
+  (tree-union '((bin ls touch)
+                (bin make)
+                (bin awk gawk))))
+
+(test-equal "tree-union, several levels"
+  '((share (doc (make README) (coreutils README)))
+    (bin ls touch make))
+  (tree-union '((bin ls touch)
+                (share (doc (coreutils README)))
+                (bin make)
+                (share (doc (make README))))))
+
+(test-skip (if %store 0 1))
+
+(test-assert "union-build"
+  (let* ((inputs  (map (match-lambda
+                        ((name package)
+                         `(,name ,(package-derivation %store package))))
+                       (@@ (distro packages base) %bootstrap-inputs)))
+         (builder `(begin
+                     (use-modules (guix build union))
+                     (union-build (assoc-ref %outputs "out")
+                                  (map cdr %build-inputs))))
+         (drv
+          (build-expression->derivation %store "union-test"
+                                        (%current-system)
+                                        builder inputs
+                                        #:modules '((guix build union)))))
+    (and (build-derivations %store (list (pk 'drv drv)))
+         (with-directory-excursion (derivation-path->output-path drv)
+           (and (file-exists? "bin/touch")
+                (file-exists? "bin/gcc")
+                (file-exists? "bin/ld")
+                (file-exists? "lib/libc.so")
+                (directory-exists? "lib/gcc")
+                (file-exists? "include/unistd.h"))))))
+
+(test-end)
+
+
+(exit (= (test-runner-fail-count (test-runner-current)) 0))
+
+;;; Local Variables:
+;;; eval: (put 'test-assert 'scheme-indent-function 1)
+;;; eval: (put 'test-equal 'scheme-indent-function 1)
+;;; eval: (put 'call-with-input-string 'scheme-indent-function 1)
+;;; End: