Unittests run without error when done individually, but when unittesting the package some fail

[pineapple via Digitalmars-d-learn]

How this could possibly be happening is confounding me and I have 
no idea if it's something I missed or some contrived compiler bug.

This is the package.d that previously I've compiled with unittest 
every so often as a way of doing regression testing - 
https://github.com/pineapplemachine/mach.d/blob/master/mach/range/package.d

Currently, when compiled as is, tests in `indexof` and `contains` 
(a depending module) fail. If those two are commented out, 
everything else passes. If either of those modules is unittested 
individually, rather than with the others as part of the package, 
everything passes.

What's going on here?