t5551: make EXPENSIVE test cheaper

We create 50,000 tags to check that we don't overflow the
command-line of fetch-pack. But by using run_with_cmdline_limit,
we can get the same effect with a much smaller number of
tags. This makes the test fast enough that we can drop the
EXPENSIVE prereq, which means people will actually run it.

It was not documented to do so, but this test was also the
only test of a clone-over-http that requires multiple POSTs
during the conversation. We can continue to test that by
dropping http.postbuffer to its minimum size, and checking
that we get two POSTs.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t5551-http-fetch-smart.sh

@@ -213,10 +213,10 @@ test_expect_success 'cookies stored in http.cookiefile when http.savecookies set
 	test_cmp expect_cookies.txt cookies_tail.txt
 '
 
-test_expect_success EXPENSIVE 'create 50,000 tags in the repo' '
+test_expect_success 'create 2,000 tags in the repo' '
 	(
 	cd "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
-	for i in `test_seq 50000`
+	for i in $(test_seq 2000)
 	do
 		echo "commit refs/heads/too-many-refs"
 		echo "mark :$i"
@@ -237,13 +237,22 @@ test_expect_success EXPENSIVE 'create 50,000 tags in the repo' '
 	)
 '
 
-test_expect_success EXPENSIVE 'clone the 50,000 tag repo to check OS command line overflow' '
-	git clone $HTTPD_URL/smart/repo.git too-many-refs &&
+test_expect_success CMDLINE_LIMIT \
+	'clone the 2,000 tag repo to check OS command line overflow' '
+	run_with_limited_cmdline git clone $HTTPD_URL/smart/repo.git too-many-refs &&
 	(
 		cd too-many-refs &&
-		test $(git for-each-ref refs/tags | wc -l) = 50000
+		git for-each-ref refs/tags >actual &&
+		test_line_count = 2000 actual
 	)
 '
 
+test_expect_success 'large fetch-pack requests can be split across POSTs' '
+	GIT_CURL_VERBOSE=1 git -c http.postbuffer=65536 \
+		clone --bare "$HTTPD_URL/smart/repo.git" split.git 2>err &&
+	grep "^> POST" err >posts &&
+	test_line_count = 2 posts
+'
+
 stop_httpd
 test_done