1 min lesson
Test the financial logic
Work through the cases in "Test the financial logic", pairing each signal with the move that fits.
Step 1 of 2
Test the financial logicwhere finance engineering earns its keep
A usage-rating function and an ASC 606The US revenue-recognition standard; cited as the canonical judgment-heavy accounting work to keep human-led rather than hand to an agent, because facts and circumstances vary deal to deal. Press Enter for the full definition. allocation are pure logic with right answers.
Fixture a contract, assert the schedule and the invoice line.
Edge cases earn tests: mid-period upgrades, true-ups, refunds.
Sum of subledger should tie to GL; metered usage should tie to billed usage.
Run these continuously, not only at close.
A failing recon is a failing build, surfaced before an auditor finds it.
Data fixtures are the unglamorous enabler. A small library of representative contracts, usage records and payments lets every test run deterministically and lets you reproduce a production bug in the sandbox instead of guessing.
“I treat the billing config as a codebase. Everything lives in Git, every change is a reviewed PR that runs unit tests and a reconciliation suite in CI and we promote sandbox to staging to prod under change control. That gives me velocity and an audit trail from the same workflow - the review that protects the close is the same review that catches bugs.”