使用HttpTestingController拦截http请求，获取请求的查询参数，然后对其进行解析，为查询参数添加缺少的符号或删除多余的符号。示例代码如下：

it('should split query params correctly', () => {
  const queryParams = {
    param1: 'value1',
    param2: 'value2'
  }
  service.getSomeData(queryParams).subscribe();
  const req = httpMock.expectOne('http://example.com/data?param1=value1¶m2=value2')
  expect(req.request.method).toBe('GET');
  const newParams = {};
  const oldParams = req.request.params.keys();
  oldParams.forEach(param => {
    const pieces = param.split(/[&=]/g)
    if (pieces.length === 2) {
      newParams[pieces[0]] = pieces[1];
    } else {
      const lastIndex = pieces.length - 2;
      for (let i = 0; i <= lastIndex; i += 2) {
        newParams[pieces[i]] = pieces[i + 1];
      }
    }
  })
  expect(newParams).toEqual(queryParams);
});