diff --git a/tests/version-resolve.test.ts b/tests/version-resolve.test.ts
new file mode 100644
index 00000000..175c91af
--- /dev/null
+++ b/tests/version-resolve.test.ts
@@ -0,0 +1,48 @@
+import { mkdtempSync, mkdirSync, writeFileSync, existsSync, rmdirSync, rmSync } from 'node:fs';
+import { join } from 'node:path';
+import { tmpdir } from 'node:os';
+import { resolvePackageVersion } from '../src/lib/version';
+
+describe('resolvePackageVersion', () => {
+  let tempRoot: string;
+
+  beforeEach(() => {
+    tempRoot = mkdtempSync(join(tmpdir(), 'version-test-'));
+  });
+
+  afterEach(() => {
+    if (existsSync(tempRoot)) {
+      rmSync(tempRoot, { recursive: true, force: true });
+    }
+  });
+
+  it('returns version "1.2.3" when package.json has version "1.2.3"', () => {
+    const packageJson = JSON.stringify({ version: '1.2.3' });
+    writeFileSync(join(tempRoot, 'package.json'), packageJson);
+    const fromDir = join(tempRoot, 'dist', 'cli'); 
+    const result = resolvePackageVersion(fromDir);
+    expect(result).toBe('1.2.3');
+  });
+
+  it('returns "unknown" when package.json has empty version', () => {
+    const packageJson = JSON.stringify({ version: '' });
+    writeFileSync(join(tempRoot, 'package.json'), packageJson);
+    const fromDir = join(tempRoot, 'dist', 'cli'); 
+    const result = resolvePackageVersion(fromDir);
+    expect(result).toBe('unknown');
+  });
+
+  it('returns "unknown" when package.json has non-string version', () => {
+    const packageJson = JSON.stringify({ version: 5 });
+    writeFileSync(join(tempRoot, 'package.json'), packageJson);
+    const fromDir = join(tempRoot, 'dist', 'cli'); 
+    const result = resolvePackageVersion(fromDir);
+    expect(result).toBe('unknown');
+  });
+
+  it('returns "unknown" when package.json does not exist', () => {
+    const fromDir = join(tempRoot, 'dist', 'cli'); 
+    const result = resolvePackageVersion(fromDir);
+    expect(result).toBe('unknown');
+  });
+});