[PATCH 4/5] Add tests for using symbolic refs as branch name aliases.

[Johan Herland <johan@herland.net>]

A branch name alias is an alternative name for a branch, that is in most
respects equivalent to using the proper branch name. It is implemented as
a symbolic ref from the alias to the proper branch name.

Currently branch aliases work well up to the point where you try to delete
them (with "git branch -d"), at which point they incorrectly delete the
proper branch name instead of the alias. This is reflected in these tests,
and will be fixed in a subsequent patch.

Signed-off-by: Johan Herland <johan@herland.net>
---
 t/t3220-symbolic-ref-as-branch-alias.sh | 53 +++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100755 t/t3220-symbolic-ref-as-branch-alias.sh

diff --git a/t/t3220-symbolic-ref-as-branch-alias.sh b/t/t3220-symbolic-ref-as-branch-alias.sh
new file mode 100755
index 0000000..39f3a33
--- /dev/null
+++ b/t/t3220-symbolic-ref-as-branch-alias.sh
@@ -0,0 +1,53 @@
+#!/bin/sh
+
+test_description='Using a symbolic ref as a branch name alias
+
+This test uses refs/heads/alias as a symbolic ref to refs/heads/master, and
+verifies that it works as a branch name alias, namely:
+ - commits on "master" are automatically reflected on "alias"
+ - creating or deleting "alias" does not affect "master"
+ - the "alias" is not broken by "git gc"
+'
+. ./test-lib.sh
+
+test_expect_success 'prepare a trivial repository' '
+	echo Hello > A &&
+	git add A &&
+	git commit -m "Hello" &&
+	git rev-parse --verify HEAD > expect
+'
+
+test_expect_success 'create symref: refs/heads/alias -> refs/heads/master' '
+	git symbolic-ref refs/heads/alias refs/heads/master &&
+	git rev-parse --verify master > master &&
+	git rev-parse --verify alias > alias &&
+	test_cmp expect master &&
+	test_cmp expect alias
+'
+
+test_expect_success '"git gc" does not change "alias" symref' '
+	git gc &&
+	git rev-parse --verify master > master &&
+	git rev-parse --verify alias > alias &&
+	test_cmp expect master &&
+	test_cmp expect alias
+'
+
+test_expect_success 'commits are reflected through "alias" symref' '
+	echo World >> A &&
+	git commit -am "A" &&
+	git rev-parse --verify HEAD > expect &&
+	git rev-parse --verify master > master &&
+	git rev-parse --verify alias > alias &&
+	test_cmp expect master &&
+	test_cmp expect alias
+'
+
+test_expect_failure '"branch -d" deletes the "alias" symref' '
+	git branch -d alias &&
+	git rev-parse --verify master > master &&
+	test_must_fail git rev-parse --verify alias &&
+	test_cmp expect master
+'
+
+test_done
-- 
1.7.12.1.609.g5cd6968