Fix Unit tests failing due to culture differences

[Frooxius]

A number of the Unit tests have been failing on my system straight out of the box, without making any modifications to the library.

I have found that this is due to the system culture being simply assumed to be English / US in some places, but my system culture is actually Czech, so some numbers/things parse/format differently.

This PR fixes those unit tests to respect the provided culture information, rather than just assuming, which makes all the tests fail on my system.