[PATCH v4 37/39] ci: run tests with SHA-256

Now that we have Git supporting SHA-256, we'd like to make sure that we
don't regress that state.  Unfortunately, it's easy to do so, so to
help, let's add code to run one of our CI jobs with SHA-256 as the
default hash.  This will help us detect any problems that may occur.

We pick the linux-clang job because it's relatively fast and the
linux-gcc job already runs the testsuite twice.  We want our tests to
run as fast as possible, so we wouldn't want to add a third run to the
linux-gcc job.  To make sure we properly exercise the code, let's run
the tests in the default mode (SHA-1) first and then run a second time
with SHA-256.

Signed-off-by: brian m. carlson <redacted>
---
 ci/run-build-and-tests.sh | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/ci/run-build-and-tests.sh b/ci/run-build-and-tests.sh
index 17e25aade9..a1a6a28791 100755
--- a/ci/run-build-and-tests.sh
+++ b/ci/run-build-and-tests.sh

@@ -24,6 +24,11 @@ linux-gcc)
 	export GIT_TEST_ADD_I_USE_BUILTIN=1
 	make test
 	;;
+linux-clang)
+	make test
+	export GIT_TEST_DEFAULT_HASH=sha256
+	make test
+	;;
 linux-gcc-4.8)
 	# Don't run the tests; we only care about whether Git can be
 	# built with GCC 4.8, as it errors out on some undesired (C99)