diff --git a/Makefile b/Makefile
index 302b86354850c3..ca6b38069c002d 100644
--- a/Makefile
+++ b/Makefile
@@ -1346,6 +1346,7 @@ UNIT_TEST_PROGRAMS += t-basic
 UNIT_TEST_PROGRAMS += t-mem-pool
 UNIT_TEST_PROGRAMS += t-strbuf
 UNIT_TEST_PROGRAMS += t-ctype
+UNIT_TEST_PROGRAMS += t-sha256
 UNIT_TEST_PROGS = $(patsubst %,$(UNIT_TEST_BIN)/%$X,$(UNIT_TEST_PROGRAMS))
 UNIT_TEST_OBJS = $(patsubst %,$(UNIT_TEST_DIR)/%.o,$(UNIT_TEST_PROGRAMS))
 UNIT_TEST_OBJS += $(UNIT_TEST_DIR)/test-lib.o
diff --git a/t/unit-tests/t-sha256.c b/t/unit-tests/t-sha256.c
new file mode 100644
index 00000000000000..6c7f70ca19b6a4
--- /dev/null
+++ b/t/unit-tests/t-sha256.c
@@ -0,0 +1,102 @@
+#include "test-lib.h"
+#include "hash-ll.h"
+#include "hex.h"
+
+static const char out_file[] = "./output.txt";
+
+static void hash_impl(const char **av, int algo) {
+	git_hash_ctx ctx;
+	unsigned char hash[GIT_MAX_HEXSZ];
+	unsigned bufsz = 8192;
+	int binary = 0;
+	char *buffer;
+	const struct git_hash_algo *algop = &hash_algos[algo];
+	FILE *file;
+	size_t data_length;
+
+	int ac = 0;
+	while (av[ac] != NULL) {
+		ac++;
+	}
+
+	if (ac > 1) {
+		if (!strcmp(av[1], "-b")) {
+			binary = 1;
+			if (ac > 2) {
+				bufsz = strtoul(av[2], NULL, 10) * 1024 * 1024;
+			}
+		} else {
+			bufsz = strtoul(av[1], NULL, 10) * 1024 * 1024;
+		}
+	}
+
+	if (!bufsz)
+		bufsz = 8192;
+
+	while ((buffer = malloc(bufsz)) == NULL) {
+		fprintf(stderr, "bufsz %u is too big, halving...\n", bufsz);
+		bufsz /= 2;
+		if (bufsz < 1024)
+			die("OOPS");
+	}
+
+	algop->init_fn(&ctx);
+
+	data_length = strlen(av[0]);
+
+	algop->update_fn(&ctx, av[0], data_length);
+
+	algop->final_fn(hash, &ctx);
+
+	file = freopen(out_file, "wb", stderr);
+	if (!check(!!file)) {
+		test_msg("Error opening file %s", out_file);
+		return;
+	}
+
+	if (binary)
+		fwrite(hash, 1, algop->rawsz, file);
+	else
+		puts(hash_to_hex_algop(hash, algop));
+
+	fclose(file);
+	free(buffer);
+}
+
+static char *grep(const char *pattern, const char *filename) {
+	char *result;
+	char line[1000];
+	FILE *file = fopen(out_file, "r");
+	if (!check(!!file)) {
+		test_msg("Error opening file %s", out_file);
+		return NULL;
+	}
+
+	while (fgets(line, sizeof(line), file)) {
+		if (strstr(line, pattern)) {
+			fclose(file);
+
+			result = strdup(line);
+			if (!result) {
+				fprintf(stderr, "Memory allocation error\n");
+				return NULL;
+			}
+			return result;
+		}
+	}
+
+	fclose(file);
+	return NULL;
+}
+
+static void check_sha256(const char **input, const char *expected) {
+	hash_impl(input, GIT_HASH_SHA256);
+	check_str(grep(expected, out_file), expected);
+}
+
+int cmd_main(int argc, const char **argv) {
+	const char *av[] = {"a", NULL};
+	TEST(check_sha256(av, "ca978112ca1bbdcafac231b39a23dc4da786eff8147c4e72b9807785afee48bb"), "SHA256 a works");
+
+	return test_done();
+}