test(01-03): add failing tests for level definitions

- 13 tests covering levels array, key progressions, finger mappings
- Tests for getLevelByNumber and getKeysUpToLevel helpers

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/game/levels.test.ts

@@ -0,0 +1,99 @@
+import { describe, expect, it } from "vitest";
+import { getKeysUpToLevel, getLevelByNumber, levels } from "./levels";
+
+describe("levels", () => {
+	it("has exactly 6 entries", () => {
+		expect(levels).toHaveLength(6);
+	});
+
+	it("Level 1 newKeys = ['f', 'j', ' ']", () => {
+		expect(levels[0].newKeys).toEqual(["f", "j", " "]);
+	});
+
+	it("Level 2 newKeys = ['d', 'k']", () => {
+		expect(levels[1].newKeys).toEqual(["d", "k"]);
+	});
+
+	it("Level 3 newKeys = ['s', 'l']", () => {
+		expect(levels[2].newKeys).toEqual(["s", "l"]);
+	});
+
+	it("Level 4 newKeys = ['a', 'ö']", () => {
+		expect(levels[3].newKeys).toEqual(["a", "ö"]);
+	});
+
+	it("Level 5 newKeys = ['g', 'h']", () => {
+		expect(levels[4].newKeys).toEqual(["g", "h"]);
+	});
+
+	it("Level 6 newKeys = ['e', 'i']", () => {
+		expect(levels[5].newKeys).toEqual(["e", "i"]);
+	});
+
+	it("Level 3 allKeys includes all keys from levels 1-3", () => {
+		const expected = ["f", "j", " ", "d", "k", "s", "l"];
+		for (const key of expected) {
+			expect(levels[2].allKeys).toContain(key);
+		}
+		expect(levels[2].allKeys).toHaveLength(expected.length);
+	});
+
+	it("Level 6 allKeys contains 13 keys", () => {
+		expect(levels[5].allKeys).toHaveLength(13);
+		const expected = [
+			"f",
+			"j",
+			" ",
+			"d",
+			"k",
+			"s",
+			"l",
+			"a",
+			"ö",
+			"g",
+			"h",
+			"e",
+			"i",
+		];
+		for (const key of expected) {
+			expect(levels[5].allKeys).toContain(key);
+		}
+	});
+
+	it("each key in allKeys has a fingerMap entry", () => {
+		for (const level of levels) {
+			for (const key of level.allKeys) {
+				expect(level.fingerMap[key]).toBeDefined();
+				expect(level.fingerMap[key]).toMatch(/^--finger-/);
+			}
+		}
+	});
+});
+
+describe("getLevelByNumber", () => {
+	it("returns level 1 object", () => {
+		const level = getLevelByNumber(1);
+		expect(level).toBeDefined();
+		expect(level?.level).toBe(1);
+		expect(level?.newKeys).toEqual(["f", "j", " "]);
+	});
+
+	it("returns undefined for non-existent level", () => {
+		expect(getLevelByNumber(99)).toBeUndefined();
+	});
+});
+
+describe("getKeysUpToLevel", () => {
+	it("returns cumulative keys for levels 1-3", () => {
+		const keys = getKeysUpToLevel(3);
+		const expected = ["f", "j", " ", "d", "k", "s", "l"];
+		expect(keys).toHaveLength(expected.length);
+		for (const key of expected) {
+			expect(keys).toContain(key);
+		}
+	});
+
+	it("returns empty array for non-existent level", () => {
+		expect(getKeysUpToLevel(99)).toEqual([]);
+	});
+});