Integrate mypy

[sobolevn]

When #258 will be ready the next step is to integrate mypy.

There is a standalone script.
And there's a plugin for pytest, but I have not used it yet. https://pypi.python.org/pypi/pytest-mypy

[lk-geimfari]

@sammyshj Excellent. It will be awesome!

[lk-geimfari]

@sobolevn Unfortunately, the solution with pytest-mypy works slowly... too slowly: 3m 42s 840ms

[lk-geimfari]

Also it's doesn't support mypy.ini file. It's a problem.

[lk-geimfari]

I think that i'll rewrite plugin especially for us.

[sobolevn]

@lk-geimfari this plugin is not production ready, that's true. But maybe you should help with its development instead of rewriting it?

[lk-geimfari]

@sobolevn Of course, I'll write to the author and if he agrees, I'll work on current plugin. Rewriting is an extreme measure.

[lk-geimfari]

@sobolevn How should we check types? Should we check types with usual tests or after ones?

Let me illustrate ideas:

py.test --verbose --color=yes --mypy mimesis ./

or

make test # 
make type-check #

The problem with co-testing is that mypy takes a considerable amount of time.

[sobolevn]

What's the timings for tests and type checking?

[lk-geimfari]

@sobolevn I have run py.test 7 minutes ago and testing still going.

UPD: Testing took 12 minutes.

[sobolevn]

mypy must be way faster. So, it is easier to run fast tests first, then slow tests.
I will also open a new issue to optimize tests speed.

[lk-geimfari]

Fixed in #299