t/: migrate helper/test-oidtree.c to unit-tests/t-oidtree.c

helper/test-oidtree.c along with t0069-oidtree.sh test the oidtree.h
library, which is a wrapper around crit-bit tree. Migrate them to
the unit testing framework for better debugging and runtime
performance. Along with the migration, add an extra check for
oidtree_each() test, which showcases how multiple expected matches can
be given to check_each() helper.

To achieve this, introduce a new library called 'lib-oid.h'
exclusively for the unit tests to use. It currently mainly includes
utility to generate object_id from an arbitrary hex string
(i.e. '12a' -> '12a0000000000000000000000000000000000000'). This also
handles the hash algo selection based on GIT_TEST_DEFAULT_HASH.
This library will also be helpful when we port other unit tests such
as oid-array, oidset etc.

Helped-by: Junio C Hamano <gitster@pobox.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Signed-off-by: Ghanshyam Thakkar <shyamthakkar001@gmail.com>
[jc: small fixlets squashed in]
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 52 insertions, 0 deletions

diff --git a/t/unit-tests/lib-oid.c b/t/unit-tests/lib-oid.c
new file mode 100644
index 0000000000..37105f0a8f
--- /dev/null
+++ b/t/unit-tests/lib-oid.c
@@ -0,0 +1,52 @@
+#include "test-lib.h"
+#include "lib-oid.h"
+#include "strbuf.h"
+#include "hex.h"
+
+static int init_hash_algo(void)
+{
+	static int algo = -1;
+
+	if (algo < 0) {
+		const char *algo_name = getenv("GIT_TEST_DEFAULT_HASH");
+		algo = algo_name ? hash_algo_by_name(algo_name) : GIT_HASH_SHA1;
+
+		if (!check(algo != GIT_HASH_UNKNOWN))
+			test_msg("BUG: invalid GIT_TEST_DEFAULT_HASH value ('%s')",
+				 algo_name);
+	}
+	return algo;
+}
+
+static int get_oid_arbitrary_hex_algop(const char *hex, struct object_id *oid,
+				       const struct git_hash_algo *algop)
+{
+	int ret;
+	size_t sz = strlen(hex);
+	struct strbuf buf = STRBUF_INIT;
+
+	if (!check(sz <= algop->hexsz)) {
+		test_msg("BUG: hex string (%s) bigger than maximum allowed (%lu)",
+			 hex, (unsigned long)algop->hexsz);
+		return -1;
+	}
+
+	strbuf_add(&buf, hex, sz);
+	strbuf_addchars(&buf, '0', algop->hexsz - sz);
+
+	ret = get_oid_hex_algop(buf.buf, oid, algop);
+	if (!check_int(ret, ==, 0))
+		test_msg("BUG: invalid hex input (%s) provided", hex);
+
+	strbuf_release(&buf);
+	return ret;
+}
+
+int get_oid_arbitrary_hex(const char *hex, struct object_id *oid)
+{
+	int hash_algo = init_hash_algo();
+
+	if (!check_int(hash_algo, !=, GIT_HASH_UNKNOWN))
+		return -1;
+	return get_oid_arbitrary_hex_algop(hex, oid, &hash_algos[hash_algo]);
+}