After a long and constructive conversation with ugexe++ in IRC this is IMO the least-surprise-for-the-most-people balance point as to what to do about test files finding their libs.
After a long and constructive conversation with ugexe++ in IRC
this is IMO the least-surprise-for-the-most-people balance
point as to what to do about test files finding their libs.

1) Naive users can just perl6 t/test.t
2) For that use case blib/lib is first, if you have one, like
from inside a .panda_work directory.
3) Automated utilities should not care -- they will either
build from within the package directory or know better
than to build with preexisting system ./lib or ./blib in their CWD.
4) The case where people are expecting precomps to be
someplace other than blib/lib should be rare
5) The case where people are simultaneously reaching out from
inside a directory that has a different lib/Sum or blib/Sum
and typing a full path to our test files should also be rare.
6) Data files can reasonably be assumed to stay alongside us in
t/ where they started, so use $?FILE to find them.

Now to see if panda likes it.

skids/perl6sum