git: Add 'commit-difference'.

* guix/git.scm (commit-closure, commit-difference): New procedures.
* guix/tests/git.scm, tests/git.scm: New files.
* Makefile.am (dist_noinst_DATA): Add guix/tests/git.scm.
(SCM_TESTS): Add tests/git.scm.

1 files changed, 99 insertions, 0 deletions

diff --git a/tests/git.scm b/tests/git.scm
new file mode 100644
index 0000000000..8ba10ece51
--- /dev/null
+++ b/tests/git.scm
@@ -0,0 +1,99 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2019 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-git)
+  #:use-module (git)
+  #:use-module (guix git)
+  #:use-module (guix tests git)
+  #:use-module (guix build utils)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-64))
+
+;; Test the (guix git) tools.
+
+(test-begin "git")
+
+;; 'with-temporary-git-repository' relies on the 'git' command.
+(unless (which (git-command)) (test-skip 1))
+(test-assert "commit-difference, linear history"
+  (with-temporary-git-repository directory
+      '((add "a.txt" "A")
+        (commit "first commit")
+        (add "b.txt" "B")
+        (commit "second commit")
+        (add "c.txt" "C")
+        (commit "third commit")
+        (add "d.txt" "D")
+        (commit "fourth commit"))
+    (with-repository directory repository
+      (let ((commit1 (find-commit repository "first"))
+            (commit2 (find-commit repository "second"))
+            (commit3 (find-commit repository "third"))
+            (commit4 (find-commit repository "fourth")))
+        (and (lset= eq? (commit-difference commit4 commit1)
+                    (list commit2 commit3 commit4))
+             (lset= eq? (commit-difference commit4 commit2)
+                    (list commit3 commit4))
+             (equal? (commit-difference commit3 commit2)
+                     (list commit3))
+
+             ;; COMMIT4 is not an ancestor of COMMIT1 so we should get the
+             ;; empty list.
+             (null? (commit-difference commit1 commit4)))))))
+
+(unless (which (git-command)) (test-skip 1))
+(test-assert "commit-difference, fork"
+  (with-temporary-git-repository directory
+      '((add "a.txt" "A")
+        (commit "first commit")
+        (branch "devel")
+        (checkout "devel")
+        (add "devel/1.txt" "1")
+        (commit "first devel commit")
+        (add "devel/2.txt" "2")
+        (commit "second devel commit")
+        (checkout "master")
+        (add "b.txt" "B")
+        (commit "second commit")
+        (add "c.txt" "C")
+        (commit "third commit")
+        (merge "devel" "merge")
+        (add "d.txt" "D")
+        (commit "fourth commit"))
+    (with-repository directory repository
+      (let ((master1 (find-commit repository "first commit"))
+            (master2 (find-commit repository "second commit"))
+            (master3 (find-commit repository "third commit"))
+            (master4 (find-commit repository "fourth commit"))
+            (devel1  (find-commit repository "first devel"))
+            (devel2  (find-commit repository "second devel"))
+            (merge   (find-commit repository "merge")))
+        (and (equal? (commit-difference master4 merge)
+                     (list master4))
+             (lset= eq? (commit-difference master3 master1)
+                    (list master3 master2))
+             (lset= eq? (commit-difference devel2 master1)
+                    (list devel2 devel1))
+
+             ;; The merge occurred between MASTER2 and MASTER4 so here we
+             ;; expect to see all the commits from the "devel" branch in
+             ;; addition to those on "master".
+             (lset= eq? (commit-difference master4 master2)
+                    (list master4 merge master3 devel1 devel2)))))))
+
+(test-end "git")