ci: run unit tests in CI

Run unit tests in both Cirrus and GitHub CI. For sharded CI instances
(currently just Windows on GitHub), run only on the first shard. This is
OK while we have only a single unit test executable, but we may wish to
distribute tests more evenly when we add new unit tests in the future.

We may also want to add more status output in our unit test framework,
so that we can do similar post-processing as in
ci/lib.sh:handle_failed_tests().

Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

.cirrus.yml

@@ -19,4 +19,4 @@ freebsd_12_task:
   build_script:
     - su git -c gmake
   test_script:
-    - su git -c 'gmake test'
+    - su git -c 'gmake DEFAULT_UNIT_TEST_TARGET=unit-tests-prove test unit-tests'

ci/run-build-and-tests.sh

@@ -49,6 +49,8 @@ if test -n "$run_tests"
 then
 	group "Run tests" make test ||
 	handle_failed_tests
+	group "Run unit tests" \
+		make DEFAULT_UNIT_TEST_TARGET=unit-tests-prove unit-tests
 fi
 check_unignored_build_artifacts
 

ci/run-test-slice.sh

@@ -15,4 +15,9 @@ group "Run tests" make --quiet -C t T="$(cd t &&
 	tr '\n' ' ')" ||
 handle_failed_tests
 
+# We only have one unit test at the moment, so run it in the first slice
+if [ "$1" == "0" ] ; then
+	group "Run unit tests" make --quiet -C t unit-tests-prove
+fi
+
 check_unignored_build_artifacts