Add a very basic test script for git mergetool

Signed-off-by: NCharles Bailey <charles@hashpling.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

t/t7610-mergetool.sh

+#!/bin/sh
+#
+# Copyright (c) 2008 Charles Bailey
+#
+
+test_description='git-mergetool
+
+Testing basic merge tool invocation'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+    echo master >file1 &&
+    git add file1 &&
+    git commit -m "added file1" &&
+    git checkout -b branch1 master &&
+    echo branch1 change >file1 &&
+    echo branch1 newfile >file2 &&
+    git add file1 file2 &&
+    git commit -m "branch1 changes" &&
+    git checkout -b branch2 master &&
+    echo branch2 change >file1 &&
+    echo branch2 newfile >file2 &&
+    git add file1 file2 &&
+    git commit -m "branch2 changes" &&
+    git checkout master &&
+    echo master updated >file1 &&
+    echo master new >file2 &&
+    git add file1 file2 &&
+    git commit -m "master updates"
+'
+
+test_expect_success 'custom mergetool' '
+    git config merge.tool mytool &&
+    git config mergetool.mytool.cmd "cat \"\$REMOTE\" >\"\$MERGED\"" &&
+    git config mergetool.mytool.trustExitCode true &&
+	git checkout branch1 &&
+    ! git merge master >/dev/null 2>&1 &&
+    ( yes "" | git mergetool file1>/dev/null 2>&1 ) &&
+    ( yes "" | git mergetool file2>/dev/null 2>&1 ) &&
+    test "$(cat file1)" = "master updated" &&
+    test "$(cat file2)" = "master new" &&
+	git commit -m "branch1 resolved with mergetool"
+'
+
+test_done