The tests relied on Python2 relative import semantics. Python3 changed
import semantics to always search sys.path by default. To import using a
relative path it must have a leading dot.
Forward compatible with newer Pythons.
Works towards the goal of moving tests outside of the installed package.
For more information, see PEP-328:
https://www.python.org/dev/peps/pep-0328/
There is no need to import testutils.unittest instead of simply
unittest. They are simple aliases. Use system unittest to be more
regular, consistent as well as idiomatic with the wider Python
community.
It's not so much about tests being slow: some just get stuck and timeout
travis.
Skipped all tests taking about more than 0.2s to run on my laptop.
Fast testing takes about 8s instead of 24.
Dropped cyclic import from modules to tests: they were only working
because a second copy of the package was found in the project dir.
Use relative import so that 2to3 can do a good conversion.
Explicit comparison with the tuple is required if we want to make
Notify() == (pid, channel) work: item access is not enough (and a test
in the suite fails if we get this wrong).
