rmgen library tests

[elexis]

Once the rmgen library is sorted well (#4804), we could start testing their correctness.

For instance the math.js functions.
Placers could be tested that they have a place function that returns an array of points or undefined.
Centered Placers could be tested that they do have an x and z property.
It could be tested that creating a new Map produces a map of the correct gridsize,
that out-of-bound access to the grid throws an error,
that a Constraint does what it should and so forth.

[FeXoR]

Replying to elexis:

[...] Centered Placers could be tested that they do have an x and z property.

Shouldn't they have a "center" propperty which is a vector2D?

[elexis]

As of #4992, yes

[elexis]

In 23455:

Support random map script tests, fixes #4827.

Differential Revision: ​https://code.wildfiregames.com/D2085
Comments By: wraitii

[elexis]

In 23460:

Some more random random map script unit tests and ASSERT functions, refs #4827.

Differential Revision: ​https://code.wildfiregames.com/D2603