t5801 (remote-helpers): add test to fetch tags

This used to work, but commit e198b3a740 broke it.

  e198b3a740 (fetch: replace string-list used as a look-up table with a hashmap)

Probably all remote helpers that use the import method are affected, but
we didn't catch the issue.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-remote-testgit.sh

@@ -12,9 +12,14 @@ url=$2
 
 dir="$GIT_DIR/testgit/$alias"
 
-refspec="refs/heads/*:refs/testgit/$alias/heads/*"
+h_refspec="refs/heads/*:refs/testgit/$alias/heads/*"
+t_refspec="refs/tags/*:refs/testgit/$alias/tags/*"
 
-test -n "$GIT_REMOTE_TESTGIT_NOREFSPEC" && refspec=""
+if test -n "$GIT_REMOTE_TESTGIT_NOREFSPEC"
+then
+	h_refspec=""
+	t_refspec=""
+fi
 
 GIT_DIR="$url/.git"
 export GIT_DIR
@@ -37,7 +42,8 @@ do
 	capabilities)
 		echo 'import'
 		echo 'export'
-		test -n "$refspec" && echo "refspec $refspec"
+		test -n "$h_refspec" && echo "refspec $h_refspec"
+		test -n "$t_refspec" && echo "refspec $t_refspec"
 		if test -n "$gitmarks"
 		then
 			echo "*import-marks $gitmarks"
@@ -49,7 +55,7 @@ do
 		echo
 		;;
 	list)
-		git for-each-ref --format='? %(refname)' 'refs/heads/'
+		git for-each-ref --format='? %(refname)' 'refs/heads/' 'refs/tags/'
 		head=$(git symbolic-ref HEAD)
 		echo "@$head HEAD"
 		echo
@@ -78,7 +84,8 @@ do
 
 		echo "feature done"
 		git fast-export \
-			${refspec:+"--refspec=$refspec"} \
+			${h_refspec:+"--refspec=$h_refspec"} \
+			${t_refspec:+"--refspec=$t_refspec"} \
 			${testgitmarks:+"--import-marks=$testgitmarks"} \
 			${testgitmarks:+"--export-marks=$testgitmarks"} \
 			$refs

t/t5801-remote-helpers.sh

@@ -301,4 +301,14 @@ test_expect_success 'fetch url' '
 	compare_refs server HEAD local FETCH_HEAD
 '
 
+test_expect_failure 'fetch tag' '
+	(cd server &&
+	 git tag v1.0
+	) &&
+	(cd local &&
+	 git fetch
+	) &&
+	compare_refs local v1.0 server v1.0
+'
+
 test_done