t/unit-tests: convert trailer test to use clar

Adapt trailer test file to use clar testing framework by using clar
assertions where necessary. Split test into individual test functions
for clarity and maintainability. Each test case now has its own
function, making it easier to isolate failures and improve test
readability.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Seyi Kuforiji <kuforiji98@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: Seyi007

Makefile

@@ -1361,6 +1361,7 @@ CLAR_TEST_SUITES += u-reftable-tree
 CLAR_TEST_SUITES += u-strbuf
 CLAR_TEST_SUITES += u-strcmp-offset
 CLAR_TEST_SUITES += u-strvec
+CLAR_TEST_SUITES += u-trailer
 CLAR_TEST_PROG = $(UNIT_TEST_BIN)/unit-tests$(X)
 CLAR_TEST_OBJS = $(patsubst %,$(UNIT_TEST_DIR)/%.o,$(CLAR_TEST_SUITES))
 CLAR_TEST_OBJS += $(UNIT_TEST_DIR)/clar/clar.o
@@ -1377,7 +1378,6 @@ UNIT_TEST_PROGRAMS += t-reftable-reader
 UNIT_TEST_PROGRAMS += t-reftable-readwrite
 UNIT_TEST_PROGRAMS += t-reftable-record
 UNIT_TEST_PROGRAMS += t-reftable-stack
-UNIT_TEST_PROGRAMS += t-trailer
 UNIT_TEST_PROGRAMS += t-urlmatch-normalization
 UNIT_TEST_PROGS = $(patsubst %,$(UNIT_TEST_BIN)/%$X,$(UNIT_TEST_PROGRAMS))
 UNIT_TEST_OBJS += $(UNIT_TEST_DIR)/test-lib.o

t/meson.build

@@ -9,6 +9,7 @@ clar_test_suites = [
   'unit-tests/u-strbuf.c',
   'unit-tests/u-strcmp-offset.c',
   'unit-tests/u-strvec.c',
+  'unit-tests/u-trailer.c',
 ]
 
 clar_sources = [
@@ -59,7 +60,6 @@ unit_test_programs = [
   'unit-tests/t-reftable-readwrite.c',
   'unit-tests/t-reftable-record.c',
   'unit-tests/t-reftable-stack.c',
-  'unit-tests/t-trailer.c',
   'unit-tests/t-urlmatch-normalization.c',
 ]