Setuptools now includes wheel as a dependency for editable installs

and isolated build environments, which the unit tests weren't checking

for. This is now included in the appropriate tests.
It also changed how dependency version specifiers are represented.

Instead of package>=1.0, it's now package >=1.0, with a space after

the package. This affected some tests as well, though doesn't impact

anything at package time.

All unit tests pass.