chore(blp): add tests for BLP util functions (#25)

src/spec/blp/util.spec.ts

@@ -0,0 +1,40 @@
+import { calcLevelCount, getSizeAtMipLevel } from '../../lib/blp/util.js';
+import { describe, expect, test } from 'vitest';
+
+describe('util', () => {
+  describe('calcLevelCount', () => {
+    test('should return expected level count for 512x512 dimensions', () => {
+      expect(calcLevelCount(512, 512)).toBe(10);
+    });
+
+    test('should return expected level count for 16x16 dimensions', () => {
+      expect(calcLevelCount(16, 16)).toBe(5);
+    });
+
+    test('should return expected level count for 1x1 dimensions', () => {
+      expect(calcLevelCount(1, 1)).toBe(1);
+    });
+
+    test('should return expected level count for 128x64 dimensions', () => {
+      expect(calcLevelCount(128, 64)).toBe(8);
+    });
+  });
+
+  describe('getSizeAtMipLevel', () => {
+    test('should return expected size given initial size of 512 and mip level of 0', () => {
+      expect(getSizeAtMipLevel(512, 0)).toBe(512);
+    });
+
+    test('should return expected size given initial size of 512 and mip level of 1', () => {
+      expect(getSizeAtMipLevel(512, 1)).toBe(256);
+    });
+
+    test('should return expected size given initial size of 512 and mip level of 9', () => {
+      expect(getSizeAtMipLevel(512, 9)).toBe(1);
+    });
+
+    test('should return expected size given initial size of 2 and mip level of 1', () => {
+      expect(getSizeAtMipLevel(2, 1)).toBe(1);
+    });
+  });
+});