How to run specific running usr.bin/grep tests?

I want to investigate the remaining zgrep wrapper script deficiencies 
and this requires being able to run specific tests for usr.bin/grep. 
Unfortunately it looks like I did not take notes the last time I did 
this (2020).

Given a checkout of src in /usr/src/15-CURRENT I tried the appended 
which kinda works (for some tests) but gives a bunch of warnings.

Could someone please point me in the right direction? My test/build 
system is 14.2.

		Craig

zinc 30 # cd /usr/src/15-CURRENT/usr.bin/grep/tests
zinc 31 # make
echo '#! /usr/libexec/atf-sh' > grep_test.tmp
cat /usr/src/15-CURRENT/contrib/netbsd-tests/usr.bin/grep/t_grep.sh 
 >>grep_test.tmp
chmod +x grep_test.tmp
mv grep_test.tmp grep_test
zinc 32 # /usr/obj/usr/src/amd64.amd64/usr.bin/grep/tests/grep_test 
zgrep_combined_flags
grep_test: WARNING: Running test cases outside of kyua(1) is unsupported
grep_test: WARNING: No isolation nor timeout control is being applied; 
you may get unexpected failures; see atf-test-case(4)
Executing command [ zgrep -we foo test ]
Executing command [ zgrep -wefoo test ]
Fail: stderr not empty
--- /dev/null   2025-02-05 10:58:40.451627000 -0800
+++ /tmp/check.CAnhLI/stderr    2025-02-05 10:58:40.450138000 -0800
@@ -0,0 +1 @@
+zcat: (stdin): unexpected end of file
expected_failure: known but unsolved zgrep wrapper script regression: 
atf-check failed; see the output of the test for details