test libs: rename bundle helper to "lib-bundle.sh"

Rename the recently introduced test-bundle-functions.sh to be
consistent with other lib-*.sh files, which is the convention for
these sorts of shared test library functions.

The new test-bundle-functions.sh was introduced in 9901164d81 (test:
add helper functions for git-bundle, 2021-01-11). It was the only
test-*.sh of this nature.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/lib-bundle.sh

@@ -0,0 +1,42 @@
+# Library of git-bundle related functions.
+
+# Display the pack data contained in the bundle file, bypassing the
+# header that contains the signature, prerequisites and references.
+convert_bundle_to_pack () {
+	while read x && test -n "$x"
+	do
+		:;
+	done
+	cat
+}
+
+# Check count of objects in a bundle file.
+# We can use "--thin" opiton to check thin pack, which must be fixed by
+# command `git-index-pack --fix-thin --stdin`.
+test_bundle_object_count () {
+	thin=
+	if test "$1" = "--thin"
+	then
+		thin=t
+		shift
+	fi
+	if test $# -ne 2
+	then
+		echo >&2 "args should be: <bundle> <count>"
+		return 1
+	fi
+	bundle=$1
+	pack=$bundle.pack
+	convert_bundle_to_pack <"$bundle" >"$pack" &&
+	if test -n "$thin"
+	then
+		mv "$pack" "$bundle.thin.pack" &&
+		git index-pack --stdin --fix-thin "$pack" <"$bundle.thin.pack"
+	else
+		git index-pack "$pack"
+	fi || return 1
+	count=$(git show-index <"${pack%pack}idx" | wc -l) &&
+	test $2 = $count && return 0
+	echo >&2 "error: object count for $bundle is $count, not $2"
+	return 1
+}