* allow vcs-repo-file-url to be empty Signed-off-by: Miaofei <miaofei@amazon.com> * address pr comments and add test Signed-off-by: Miaofei <miaofei@amazon.com> * attempt to fix new tests Signed-off-by: Miaofei <miaofei@amazon.com> * remove new tests, which don't work Signed-off-by: Miaofei <miaofei@amazon.com>