web-player: add Vitest, unit tests and pure queue operations

web-player/src/lib/data/genres.test.ts

@@ -0,0 +1,28 @@
+import { describe, expect, it } from 'vitest';
+import { findConflict, genreHue } from './genres';
+
+describe('genreHue', () => {
+	it('is stable and within 0-359', () => {
+		for (const genre of ['rock', 'something-unknown', 'ñandú']) {
+			const hue = genreHue(genre);
+			expect(hue).toBe(genreHue(genre));
+			expect(hue).toBeGreaterThanOrEqual(0);
+			expect(hue).toBeLessThan(360);
+		}
+	});
+});
+
+describe('findConflict', () => {
+	const options = [
+		{ genre: 'a', incompatibleWith: ['b'] },
+		{ genre: 'b', incompatibleWith: ['a'] },
+		{ genre: 'c', incompatibleWith: [] }
+	];
+	it('returns the first incompatible pair', () => {
+		expect(findConflict(['c', 'a', 'b'], options)).toEqual(['a', 'b']);
+	});
+	it('returns undefined when compatible or unknown', () => {
+		expect(findConflict(['a', 'c'], options)).toBeUndefined();
+		expect(findConflict(['x', 'y'], options)).toBeUndefined();
+	});
+});