> test-quick Create
# Create not re-run, Delete deletes the file.
> test-quick
# Re-create the file.
> test-only Create

# Non-API change
$ copy-file changed/A.scala src/main/scala/A.scala
> compile
$ sleep 2000
# Create is run. Delete is not since it doesn't have src/main dependency.
-> test-quick
> test-only Delete
# Previous run of Create failed, re-run.
> test-quick Create
# No-op.
> test-quick Create
# API change.

$ copy-file changed/B.scala src/main/scala/B.scala
> compile
$ sleep 2000
-> test-quick Create
> test-only Delete
# Previous run of Create failed, re-run.
> test-quick Create
# src/test compilation group change.

$ copy-file changed/Base.scala src/test/scala/Base.scala
> test:compile
$ sleep 2000
-> test-quick Create
> test-quick Delete
> test-quick Create