Proper mocking techniques

Use appropriate mocking approaches for different dependencies in tests to ensure accurate test results and prevent false positives. Different types of dependencies require different mocking strategies:

1. For browser APIs not implemented in JSDOM (like window.open):

   // Define and mock the property before using it
   // @ts-expect-error global.open should return a Window, but is not implemented in js-dom.
   const openSpy = jest.spyOn(global, 'open').mockReturnValue(true);
   

2. For utility functions like logging, prefer individual method mocks with cleanup: ```javascript beforeEach(() => { jest.spyOn(log, ‘error’).mockImplementation(() => {}); jest.spyOn(log, ‘warning’).mockImplementation(() => {}); jest.spyOn(log, ‘debug’).mockImplementation(() => {}); });

afterEach(() => { jest.resetAllMocks(); });

3. For module dependencies, use dedicated mocks rather than actual imports:
```javascript
// Instead of using setupDataSources which imports actual modules:
const dsServer = new MockDataSourceSrv(datasources) as unknown as DataSourceSrv;

Using precise mocking strategies improves test reliability, prevents unexpected behavior from external dependencies, and ensures tests validate exactly what you intend to test.