t0014: introduce an alias testing suite

Introduce a testing suite that is dedicated to aliases.
For now, check only if nested aliases work and if looping
aliases are detected successfully.

The looping aliases check for mixed execution is there but
disabled, because it is blocking the test suite for a full
minute. As soon as there is a solution for loops using
external commands, it should be enabled.

Signed-off-by: Tim Schumacher <timschumi@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t0014-alias.sh

@@ -0,0 +1,40 @@
+#!/bin/sh
+
+test_description='git command aliasing'
+
+. ./test-lib.sh
+
+test_expect_success 'nested aliases - internal execution' '
+	git config alias.nested-internal-1 nested-internal-2 &&
+	git config alias.nested-internal-2 status &&
+	git nested-internal-1 >output &&
+	test_i18ngrep "^On branch " output
+'
+
+test_expect_success 'nested aliases - mixed execution' '
+	git config alias.nested-external-1 nested-external-2 &&
+	git config alias.nested-external-2 "!git nested-external-3" &&
+	git config alias.nested-external-3 status &&
+	git nested-external-1 >output &&
+	test_i18ngrep "^On branch " output
+'
+
+test_expect_success 'looping aliases - internal execution' '
+	git config alias.loop-internal-1 loop-internal-2 &&
+	git config alias.loop-internal-2 loop-internal-3 &&
+	git config alias.loop-internal-3 loop-internal-2 &&
+	test_must_fail git loop-internal-1 2>output &&
+	test_i18ngrep "^fatal: alias loop detected: expansion of" output
+'
+
+# This test is disabled until external loops are fixed, because would block
+# the test suite for a full minute.
+#
+#test_expect_failure 'looping aliases - mixed execution' '
+#	git config alias.loop-mixed-1 loop-mixed-2 &&
+#	git config alias.loop-mixed-2 "!git loop-mixed-1" &&
+#	test_must_fail git loop-mixed-1 2>output &&
+#	test_i18ngrep "^fatal: alias loop detected: expansion of" output
+#'
+
+test_done