Add selftest for 'git submodule foreach'

The selftest verifies that:
- only checked out submodules are visited by 'git submodule foreach'
- the $path, and $sha1 variables are set correctly for each submodule

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t7407-submodule-foreach.sh

@@ -0,0 +1,79 @@
+#!/bin/sh
+#
+# Copyright (c) 2009 Johan Herland
+#
+
+test_description='Test "git submodule foreach"
+
+This test verifies that "git submodule foreach" correctly visits all submodules
+that are currently checked out.
+'
+
+. ./test-lib.sh
+
+
+test_expect_success 'setup a submodule tree' '
+	echo file > file &&
+	git add file &&
+	test_tick &&
+	git commit -m upstream
+	git clone . super &&
+	git clone super submodule &&
+	(
+		cd super &&
+		git submodule add ../submodule sub1 &&
+		git submodule add ../submodule sub2 &&
+		git submodule add ../submodule sub3 &&
+		git config -f .gitmodules --rename-section \
+			submodule.sub1 submodule.foo1 &&
+		git config -f .gitmodules --rename-section \
+			submodule.sub2 submodule.foo2 &&
+		git config -f .gitmodules --rename-section \
+			submodule.sub3 submodule.foo3 &&
+		git add .gitmodules
+		test_tick &&
+		git commit -m "submodules" &&
+		git submodule init sub1 &&
+		git submodule init sub2 &&
+		git submodule init sub3
+	) &&
+	(
+		cd submodule &&
+		echo different > file &&
+		git add file &&
+		test_tick &&
+		git commit -m "different"
+	) &&
+	(
+		cd super &&
+		(
+			cd sub3 &&
+			git pull
+		) &&
+		git add sub3 &&
+		test_tick &&
+		git commit -m "update sub3"
+	)
+'
+
+sub1sha1=$(cd super/sub1 && git rev-parse HEAD)
+sub3sha1=$(cd super/sub3 && git rev-parse HEAD)
+
+cat > expect <<EOF
+Entering 'sub1'
+sub1-$sub1sha1
+Entering 'sub3'
+sub3-$sub3sha1
+EOF
+
+test_expect_success 'test basic "submodule foreach" usage' '
+	git clone super clone &&
+	(
+		cd clone &&
+		git submodule update --init -- sub1 sub3 &&
+		git submodule foreach "echo \$path-\$sha1" > ../actual
+	) &&
+	test_cmp expect actual
+'
+
+test_done