test suite

[cdepillabout]

It would be nice to have a test-suite for purenix.

The most important tests would be for the Nix.Convert and Nix.Print modules.

We'd also especially like to test that all our identifiers, strings, and attrset keys get escaped correctly.

Places to pull ideas from:

• PureScript test suite: https://github.com/purescript/purescript/tree/master/tests
• purescm test suite: https://github.com/purescm/purescm/tree/master/test

As of this writing, neither purerl nor purescript-native have a test suite.

[jonascarpay]

There is some discussion relevant to this issue here: https://github.com/purenix-org/purenix/pull/44#issuecomment-1037074437