- use git_env_*() instead of manually handling getenv() values
[...]
 	struct packed_git **mapping, *p;
-	int cnt = 0, nr = 1 << OE_IN_PACK_BITS;
-
-	if (getenv("GIT_TEST_FULL_IN_PACK_ARRAY")) {
-		/*
-		 * leave in_pack_by_idx NULL to force in_pack[] to be
-		 * used instead
-		 */
-		return;
-	}
[...]

+	if (git_env_bool("GIT_TEST_FULL_IN_PACK_ARRAY", 0)) {
+		/*
+		 * do not initialize in_pack_by_idx[] to force the
+		 * slow path in oe_in_pack()
+		 */
+	} else {
+		prepare_in_pack_by_idx(pdata);
+	}
[...]

diff --git a/t/README b/t/README
index 02bfb3fed5..c01d210c15 100644
--- a/t/README
+++ b/t/README

@@ -291,16 +291,26 @@ expect the rest to function correctly.
 and know what setup is needed for it.  Or when you want to run
 everything up to a certain test.

+
+Running tests with special setups
+---------------------------------
+
+The whole test suite could be run to test some special features
+that cannot be easily covered by a few specific test cases. These
+could be enabled by running the test suite with correct GIT_TEST_
+environment set.
+
+GIT_TEST_SPLIT_INDEX forces split-index mode on the whole test suite.
+
 GIT_TEST_FULL_IN_PACK_ARRAY exercises the uncommon pack-objects code
 path where there are more than 1024 packs even if the actual number of
 packs in repository is below this limit.

-GIT_TEST_OE_SIZE_BITS=<bits> exercises the uncommon pack-objects
-code path where we do not cache objecct size in memory and read it
-from existing packs on demand. This normally only happens when the
-object size is over 2GB. This variable forces the code path on any
-object larger than 2^<bits> bytes.