fix: Add missing tests directory and files

tests/unit/errors.test.ts

@@ -0,0 +1,75 @@
+import {
+  GitAgentSyncError,
+  WorkspaceExistsError,
+  WorkspaceNotFoundError,
+  InvalidAgentNameError,
+  MergeConflictError,
+  handleError,
+  formatError
+} from '../../src/utils/errors';
+
+describe('Error classes', () => {
+  it('should create GitAgentSyncError with code', () => {
+    const error = new GitAgentSyncError('Test error', 'TEST_CODE');
+    expect(error.message).toBe('Test error');
+    expect(error.code).toBe('TEST_CODE');
+    expect(error.name).toBe('GitAgentSyncError');
+  });
+
+  it('should create WorkspaceExistsError with details', () => {
+    const error = new WorkspaceExistsError('agent-1', '/path/to/workspace');
+    expect(error.message).toContain('agent-1');
+    expect(error.message).toContain('/path/to/workspace');
+    expect(error.code).toBe('WORKSPACE_EXISTS');
+    expect(error.details?.agentName).toBe('agent-1');
+  });
+
+  it('should create WorkspaceNotFoundError', () => {
+    const error = new WorkspaceNotFoundError('agent-2');
+    expect(error.message).toContain('agent-2');
+    expect(error.code).toBe('WORKSPACE_NOT_FOUND');
+  });
+
+  it('should create InvalidAgentNameError', () => {
+    const error = new InvalidAgentNameError('invalid@name');
+    expect(error.message).toContain('invalid@name');
+    expect(error.code).toBe('INVALID_AGENT_NAME');
+  });
+
+  it('should create MergeConflictError with file list', () => {
+    const error = new MergeConflictError(['file1.ts', 'file2.ts']);
+    expect(error.message).toContain('file1.ts');
+    expect(error.message).toContain('file2.ts');
+    expect(error.code).toBe('MERGE_CONFLICT');
+  });
+});
+
+describe('handleError', () => {
+  it('should pass through GitAgentSyncError', () => {
+    const error = new GitAgentSyncError('test', 'CODE');
+    const result = handleError(error);
+    expect(result).toBe(error);
+  });
+
+  it('should wrap unknown errors', () => {
+    const result = handleError(new Error('unknown error'));
+    expect(result).toBeInstanceOf(GitAgentSyncError);
+    expect(result.message).toBe('unknown error');
+  });
+
+  it('should handle non-Error objects', () => {
+    const result = handleError('string error');
+    expect(result).toBeInstanceOf(GitAgentSyncError);
+    expect(result.message).toBe('string error');
+  });
+});
+
+describe('formatError', () => {
+  it('should format error with color and details', () => {
+    const error = new GitAgentSyncError('Test error', 'TEST_CODE', { key: 'value' });
+    const formatted = formatError(error);
+    expect(formatted).toContain('Test error');
+    expect(formatted).toContain('TEST_CODE');
+    expect(formatted).toContain('key');
+  });
+});