Parametrize shared Document tests over PurchaseInvoice and Receipt

[TimEvci]

Summary

PurchaseInvoice and Receipt are both thin subclasses of the same Document base, but their test files are independent copies with very different coverage: tests/test_purchase_invoice.py is 268 lines, tests/test_receipt.py is 51 lines and covers only five of the same test names (test_add_detail, test_delete, test_find_by_id, test_list_all, test_sync_endpoint). Everything only exercised in the purchase-invoice file — payments, detail updates/deletion with _destroy, attachments, register_payment, save round-trips — is untested for Receipt, even though the code paths are shared.

Details

Both classes differ only in _resource ("purchase_invoice" vs "receipt"), so the behavior under test is identical except for the URL segment and payload key. The current structure means:

• New Document features get tested against one subclass only (whichever file the author copies into).
• The two files drift — they already have.

Suggested fix

Parametrize the shared Document behavior over both subclasses:

@pytest.fixture(params=[PurchaseInvoice, Receipt])
def document_cls(request):
    return request.param

• Move the shared tests into a single tests/test_document.py parametrized by document_cls, deriving expected paths from cls._resource instead of hard-coding purchase_invoices.
• Keep (or add) only genuinely subclass-specific assertions in per-class files — likely just the endpoint/_resource values, which the parametrized suite covers anyway.

Result: Receipt inherits the full suite for free, total test code shrinks, and future Document subclasses get coverage by adding one fixture param.

Acceptance criteria

• Every shared Document behavior test runs against both PurchaseInvoice and Receipt.
• No duplicated test bodies between the two resource types.
• Coverage for Receipt payments/details/attachments matches PurchaseInvoice.