diff --git a/Makefile b/Makefile
index 4e255c81f2..b8d7019ad7 100644
--- a/Makefile
+++ b/Makefile
@@ -850,7 +850,6 @@ TEST_BUILTINS_OBJS += test-sha1.o
 TEST_BUILTINS_OBJS += test-sha256.o
 TEST_BUILTINS_OBJS += test-sigchain.o
 TEST_BUILTINS_OBJS += test-simple-ipc.o
-TEST_BUILTINS_OBJS += test-strcmp-offset.o
 TEST_BUILTINS_OBJS += test-string-list.o
 TEST_BUILTINS_OBJS += test-submodule-config.o
 TEST_BUILTINS_OBJS += test-submodule-nested-repo-config.o
@@ -1347,6 +1346,7 @@ UNIT_TEST_PROGRAMS += t-mem-pool
 UNIT_TEST_PROGRAMS += t-strbuf
 UNIT_TEST_PROGRAMS += t-ctype
 UNIT_TEST_PROGRAMS += t-prio-queue
+UNIT_TEST_PROGRAMS += t-strcmp-offset
 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/helper/test-strcmp-offset.c b/t/helper/test-strcmp-offset.c
deleted file mode 100644
index d8473cf2fc..0000000000
--- a/t/helper/test-strcmp-offset.c
+++ /dev/null
@@ -1,23 +0,0 @@
-#include "test-tool.h"
-#include "read-cache-ll.h"
-
-int cmd__strcmp_offset(int argc UNUSED, const char **argv)
-{
-	int result;
-	size_t offset;
-
-	if (!argv[1] || !argv[2])
-		die("usage: %s <string1> <string2>", argv[0]);
-
-	result = strcmp_offset(argv[1], argv[2], &offset);
-
-	/*
-	 * Because different CRTs behave differently, only rely on signs
-	 * of the result values.
-	 */
-	result = (result < 0 ? -1 :
-			  result > 0 ? 1 :
-			  0);
-	printf("%d %"PRIuMAX"\n", result, (uintmax_t)offset);
-	return 0;
-}
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 482a1e58a4..3d56de82fd 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -76,7 +76,6 @@ static struct test_cmd cmds[] = {
 	{ "sha256", cmd__sha256 },
 	{ "sigchain", cmd__sigchain },
 	{ "simple-ipc", cmd__simple_ipc },
-	{ "strcmp-offset", cmd__strcmp_offset },
 	{ "string-list", cmd__string_list },
 	{ "submodule", cmd__submodule },
 	{ "submodule-config", cmd__submodule_config },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index b1be7cfcf5..8d76a8c1e1 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -69,7 +69,6 @@ int cmd__oid_array(int argc, const char **argv);
 int cmd__sha256(int argc, const char **argv);
 int cmd__sigchain(int argc, const char **argv);
 int cmd__simple_ipc(int argc, const char **argv);
-int cmd__strcmp_offset(int argc, const char **argv);
 int cmd__string_list(int argc, const char **argv);
 int cmd__submodule(int argc, const char **argv);
 int cmd__submodule_config(int argc, const char **argv);
diff --git a/t/t0065-strcmp-offset.sh b/t/t0065-strcmp-offset.sh
deleted file mode 100755
index 94e34c83ed..0000000000
--- a/t/t0065-strcmp-offset.sh
+++ /dev/null
@@ -1,22 +0,0 @@
-#!/bin/sh
-
-test_description='Test strcmp_offset functionality'
-
-TEST_PASSES_SANITIZE_LEAK=true
-. ./test-lib.sh
-
-while read s1 s2 expect
-do
-	test_expect_success "strcmp_offset($s1, $s2)" '
-		echo "$expect" >expect &&
-		test-tool strcmp-offset "$s1" "$s2" >actual &&
-		test_cmp expect actual
-	'
-done <<-EOF
-abc abc 0 3
-abc def -1 0
-abc abz -1 2
-abc abcdef -1 3
-EOF
-
-test_done
diff --git a/t/unit-tests/t-strcmp-offset.c b/t/unit-tests/t-strcmp-offset.c
new file mode 100644
index 0000000000..176d2ed04a
--- /dev/null
+++ b/t/unit-tests/t-strcmp-offset.c
@@ -0,0 +1,31 @@
+#include "test-lib.h"
+#include "read-cache-ll.h"
+
+static void check_strcmp_offset(const char *string1, const char *string2, int expect_result,  uintmax_t expect_offset)
+{
+	int result;
+	size_t offset;
+
+	result = strcmp_offset(string1, string2, &offset);
+
+	/* Because different CRTs behave differently, only rely on signs of the result values. */
+	result = (result < 0 ? -1 :
+			  result > 0 ? 1 :
+			  0);
+
+	check_int(result, ==, expect_result);
+	check_uint((uintmax_t)offset, ==, expect_offset);
+}
+
+#define TEST_STRCMP_OFFSET(string1, string2, expect_result, expect_offset) \
+		TEST(check_strcmp_offset(string1, string2, expect_result, expect_offset), \
+			"strcmp_offset(%s, %s) works", #string1, #string2)
+
+int cmd_main(int argc, const char **argv) {
+	TEST_STRCMP_OFFSET("abc", "abc", 0, 3);
+	TEST_STRCMP_OFFSET("abc", "def", -1, 0);
+	TEST_STRCMP_OFFSET("abc", "abz", -1, 2);
+	TEST_STRCMP_OFFSET("abc", "abcdef", -1, 3);
+
+	return test_done();
+}
