First step to slowly giving readTree some coverage, so we can do
refactoring without breaking functionality.
Change-Id: If25a8c0fa9c4ac7472c0473372f10a9326cccaf7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2465
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI
