Organising the codebase

[willGraham01]

Is Your Feature Request Related to a Problem? Please Describe

Currently our package codebase and test suite is a bit all over the place. The test suite has a lot of repeated setup that we would ideally move into fixtures, or into setup fixtures.

The package code itself has a number of files that contain multiple "important" classes that we should probably split out for our own sanity down the line.

TLDR; It is probably time to introduce some order.

Describe the Solution You'd Like

Test Suite

The test suite is the easy one to tackle, in which I propose we organise the test suite along the lines of:

tests/
    fixtures/
    test_unit/
    test_integration/
    conftest.py

We can setup conftest.py to automatically search the fixtures directory (and any sub-directories) for pytest.fixture objects, which all tests will have access to. We can also put any "utility fixtures" in here, like helpers for pytest.raise contexts.

test_unit can then follow the structure that we seem to largely be adhering to currently. Small unit tests for methods should go in here, or inside sub-folders appropriately. Personally I prefer one-test-file-per-method-being-tested, rather than one-file-per-class-or-module, doubly so since our test files already seem to be quite long.

test_integration may or may not be needed, but essentially serves as a space for some of our larger examples. Like when we eventually introduce #45 ?

Codebase Itself

Here, I think we just need to set some rules for how modular we are. Nothing is immediately pressing, though we could be a bit more modular with our files and where we define classes. The node.py file for example defines three classes, for example - these should probably be 3 separate files within their own sub(sub)module.

Describe Alternatives You've Considered

No response

Additional Context

No response