test: optionally test contrib in CI

Recently it was reported that a topic merged to 'next' broke build
and test for contrib/subtree part of the system.

Instead of having those who run 'next' or 'master' to hit the build
and test breakage and report to us, make sure we notice breakages in
contrib/ area before they hit my tree at all, during their own
presubmit testing.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: gitster

Makefile

@@ -342,6 +342,9 @@ include shared.mak
 # If it isn't set, fallback to $LC_ALL, $LANG or use the first utf-8
 # locale returned by "locale -a".
 #
+# Define TEST_CONTRIB_TOO to make "make test" run tests in contrib/
+# directories.
+#
 # Define HAVE_CLOCK_GETTIME if your platform has clock_gettime.
 #
 # Define HAVE_CLOCK_MONOTONIC if your platform has CLOCK_MONOTONIC.
@@ -3369,6 +3372,9 @@ export TEST_NO_MALLOC_CHECK
 
 test: all
 	$(MAKE) -C t/ all
+ifdef TEST_CONTRIB_TOO
+	$(MAKE) -C contrib/ test
+endif
 
 perf: all
 	$(MAKE) -C t/perf/ all

ci/run-build-and-tests.sh

@@ -9,6 +9,7 @@ case "$jobname" in
 fedora-breaking-changes-musl|linux-breaking-changes)
 	export WITH_BREAKING_CHANGES=YesPlease
 	export WITH_RUST=YesPlease
+	export TEST_CONTRIB_TOO=yes
 	MESONFLAGS="$MESONFLAGS -Dbreaking_changes=true"
 	MESONFLAGS="$MESONFLAGS -Drust=enabled"
 	;;
@@ -26,6 +27,7 @@ linux-TEST-vars)
 	export GIT_TEST_NO_WRITE_REV_INDEX=1
 	export GIT_TEST_CHECKOUT_WORKERS=2
 	export GIT_TEST_PACK_USE_BITMAP_BOUNDARY_TRAVERSAL=1
+	export TEST_CONTRIB_TOO=yes
 	;;
 linux-clang)
 	export GIT_TEST_DEFAULT_HASH=sha1
@@ -36,6 +38,7 @@ linux-sha256)
 linux-reftable|linux-reftable-leaks|osx-reftable)
 	export GIT_TEST_DEFAULT_REF_FORMAT=reftable
 	;;
+
 esac
 
 case "$jobname" in

contrib/Makefile

@@ -0,0 +1,10 @@
+all::
+
+test::
+	$(MAKE) -C diff-highlight $@
+	$(MAKE) -C subtree $@
+
+clean::
+	$(MAKE) -C contacts $@
+	$(MAKE) -C diff-highlight $@
+	$(MAKE) -C subtree $@