XGBoost-CI / Test Google C++ test (CPU) (macos-10.15)

Hi

I sent a PR#6666 and got the following test failing:

Test: XGBoost-CI / Test Google C++ test (CPU) (macos-10.15) (pull_request)

Cmd line: cd build; ctest --exclude-regex AllTestsInDMLCUnitTests --extra-verbosebranch

Since I use Centos7 and Windows, how can I possibly test this test? Also why it is passing in Centos7 but failing in mac.

Thanks