rg-stats/src/algorithms/chunithm-rating.test.ts

A library for calculating various rhythm game stats.

import t from "tap";
import { ThrowsToSnapshot } from "../test-utils/throw-snapshot";
import { calculate } from "./chunithm-rating";

t.test("CHUNITHM Rating Tests", (t) => {
	// Test all the cutoffs for a random chart level
	// are where they should be.
	const LEVEL = 12.5;
	t.equal(calculate(1_010_000, LEVEL), LEVEL + 2.15);
	t.equal(calculate(1_007_500, LEVEL), LEVEL + 2);
	t.equal(calculate(1_005_000, LEVEL), LEVEL + 1.5);
	t.equal(calculate(1_000_000, LEVEL), LEVEL + 1);
	t.equal(calculate(975_000, LEVEL), LEVEL);
	t.equal(calculate(900_000, LEVEL), LEVEL - 5);
	t.equal(calculate(800_000, LEVEL), 3.75);
	t.equal(calculate(500_000, LEVEL), 0);
	t.equal(calculate(0, LEVEL), 0);

	// Also, lets just test some random values inbetween. This should
	// give us decent coverage of the formula.
	t.equal(calculate(987_000, LEVEL), 12.98);
	t.equal(calculate(1_008_000, LEVEL), 14.55);
	t.equal(calculate(1_003_000, LEVEL), 13.8);
	t.equal(calculate(999_000, LEVEL), 13.46);
	t.equal(calculate(980_000, LEVEL), 12.7);
	t.equal(calculate(950_000, LEVEL), 10.83);
	t.equal(calculate(810_000, LEVEL), 4.12);
	t.equal(calculate(600_000, LEVEL), 1.25);
	t.equal(calculate(50_000, LEVEL), 0);

	t.end();
});

t.test("CHUNITHM Rating Edge Cases", (t) => {
	t.equal(
		calculate(1_010_000, 0),
		2.15,
		"A perfect score on a chart with level 0 should be valid, and worth 0 + 2.15."
	);
	t.equal(calculate(0, 12.5), 0, "A score of 0 should be worth 0.");
	t.equal(calculate(0, 0), 0, "A score of 0 on a chart with level 0 should be worth 0.");

	t.end();
});

t.test("CHUNITHM Rating Validation Tests", (t) => {
	ThrowsToSnapshot(t, () => calculate(-1, 12.5), "Should throw if your score is negative.");

	ThrowsToSnapshot(
		t,
		() => calculate(1_010_001, 12.5),
		"Should throw if your score is >= 1.01million."
	);

	ThrowsToSnapshot(t, () => calculate(900_000, -1), "Should throw if chart level is negative.");

	t.end();
});