[RFC PATCH v2 6/6] t/Makefile: run unit tests alongside shell tests

[Josh Steadmon <steadmon@google.com>]

From: Jeff King <peff@peff.net>

Add a wrapper script to allow `prove` to run both shell tests and unit
tests from a single invocation. This avoids issues around running prove
twice in CI, as discussed in [1].

Additionally, this moves the unit tests into the main dev workflow, so
that errors can be spotted more quickly.

NEEDS WORK: as discussed in previous commits in this series, there's a
desire to avoid `prove` specifically and (IIUC) unnecessary
fork()/exec()ing in general on Windows. This change adds an extra exec()
for each shell and unit test execution, will that be a problem for
Windows?

[1] https://lore.kernel.org/git/pull.1613.git.1699894837844.gitgitgadget@gmail.com/

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Josh Steadmon <steadmon@google.com>
---
 t/Makefile    |  2 +-
 t/run-test.sh | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100755 t/run-test.sh

diff --git a/t/Makefile b/t/Makefile
index 6e6316c29b..6a67fc22d7 100644
--- a/t/Makefile
+++ b/t/Makefile
@@ -64,7 +64,7 @@ failed:
 	test -z "$$failed" || $(MAKE) $$failed
 
 prove: pre-clean check-chainlint $(TEST_LINT)
-	@echo "*** prove ***"; $(CHAINLINTSUPPRESS) $(PROVE) --exec '$(TEST_SHELL_PATH_SQ)' $(GIT_PROVE_OPTS) $(T) :: $(GIT_TEST_OPTS)
+	@echo "*** prove (shell & unit tests) ***"; $(CHAINLINTSUPPRESS) $(PROVE) --exec ./run-test.sh $(GIT_PROVE_OPTS) $(T) $(UNIT_TESTS) :: $(GIT_TEST_OPTS)
 	$(MAKE) clean-except-prove-cache
 
 $(T):
diff --git a/t/run-test.sh b/t/run-test.sh
new file mode 100755
index 0000000000..c29fef48dc
--- /dev/null
+++ b/t/run-test.sh
@@ -0,0 +1,13 @@
+#!/bin/sh
+
+# A simple wrapper to run shell tests via TEST_SHELL_PATH,
+# or exec unit tests directly.
+
+case "$1" in
+*.sh)
+	exec ${TEST_SHELL_PATH:-/bin/sh} "$@"
+	;;
+*)
+	exec "$@"
+	;;
+esac
-- 
2.43.0.594.gd9cf4e227d-goog