# Hold'em dealer tests

Unit tests for the money logic behind `/Casino/TexasHoldem` — the betting engine, the
side-pot calculator, the split calculator and the table state.

```bash
node --test tests/holdem/*.test.js
```

No install step, no `package.json`, no dependencies. The browser modules are plain
script-tag files that each end with a `module.exports` guard, so Node can require them
as-is; `load.js` puts them on `globalThis` under the same names they use to find each
other in the page, in the load order from `TexasHoldem.cshtml`.

## What's covered

| File | Covers |
| --- | --- |
| `potCalculator.test.js` | Main and side pots, dead money, uncalled bets, odd-cent distribution |
| `betting.test.js` | Blinds, street completion, raises reopening the action, all-in run-outs |
| `state.test.js` | Button rotation, which seats post blinds, session standings |
| `splitCalculator.test.js` | Chopped pots, odd chips, unmakeable denominations |
| `invariants.test.js` | 1000 randomised hands per property (see below) |

## Why the randomised suite exists

Every correctness bug found in this tool so far has been shape-dependent: blinds posted
to empty chairs, the button skipping past players, heads-up acting out of order, an
overbet announced as a side pot. None of them show up on a full six-handed table with
equal stacks, which is the table anyone writes a fixed example for.

`invariants.test.js` deals a thousand hands across random seat counts, random empty
chairs, random stack depths and random dealer input, and checks the things a dealer
would notice being wrong:

- chips are never created or destroyed during play
- the pot breakdown plus the uncalled returns always equal the money that went in
- paying the pot out settles it to the cent
- once uncalled chips are handed back, nobody is still betting above the whole table
- the button and both blinds always land on players who are actually in the hand

The generator is seeded, so a failure reproduces from the seed printed in the message
rather than being a flake to re-run.