Port helper/test-strcmp-offset.c to unit-tests/t-strcmp-offset.c

In the recent codebase update (8bf6fbd (Merge branch
'js/doc-unit-tests', 2023-12-09)), a new unit testing framework was
merged, providing a standardized approach for testing C code. Prior to
this update, some unit tests relied on the test helper mechanism,
lacking a dedicated unit testing framework. It's more natural to perform
these unit tests using the new unit test framework.

This commit migrates the unit tests for strcmp-offset functionality from
the legacy approach using the test-tool command
`test-tool strcmp-offset`and in helper/test-strcmp-offset.c  to the new
unit testing framework (t/unit-tests/test-lib.h).

The migration involves refactoring the tests to utilize the testing
macros provided by the framework (TEST() and check_*()).

Mentored-by: Christian Couder <[email protected]>
Signed-off-by: Achu Luma <[email protected]>

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

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 },

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);

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();
+}