chore: add more tests

tests/utils/rng.test.ts

@@ -1,5 +1,5 @@
 import { describe, it, expect } from 'vitest';
-import { createRNG } from '@/utils/rng';
+import { createRNG, Mulberry32RNG } from '@/utils/rng';
 
 describe('createRNG', () => {
     it('should create RNG with default seed', () => {
@@ -90,3 +90,47 @@ describe('createRNG', () => {
         });
     });
 });
+
+describe('Mulberry32RNG', () => {
+    it('should instantiate with default seed', () => {
+        const rng = new Mulberry32RNG();
+        expect(rng.getSeed()).toBe(1);
+    });
+
+    it('should instantiate with custom seed', () => {
+        const rng = new Mulberry32RNG(99999);
+        expect(rng.getSeed()).toBe(99999);
+    });
+
+    it('should implement RNG interface', () => {
+        const rng = new Mulberry32RNG(42);
+        
+        // Should have all RNG methods
+        expect(typeof rng.next).toBe('function');
+        expect(typeof rng.nextInt).toBe('function');
+        expect(typeof rng.setSeed).toBe('function');
+        expect(typeof rng.getSeed).toBe('function');
+    });
+
+    it('should produce same results as createRNG with same seed', () => {
+        const factoryRng = createRNG(12345);
+        const directRng = new Mulberry32RNG(12345);
+
+        for (let i = 0; i < 10; i++) {
+            expect(factoryRng.next()).toBe(directRng.next());
+            expect(factoryRng.nextInt(100)).toBe(directRng.nextInt(100));
+        }
+    });
+
+    it('should allow seed changes after instantiation', () => {
+        const rng = new Mulberry32RNG(100);
+        expect(rng.getSeed()).toBe(100);
+
+        rng.setSeed(200);
+        expect(rng.getSeed()).toBe(200);
+
+        const value = rng.next();
+        expect(value).toBeGreaterThanOrEqual(0);
+        expect(value).toBeLessThan(1);
+    });
+});