How to use the @loopback/testlab.stubExpressContext function in @loopback/testlab

function setupResponseMock() {
    const responseMock = stubExpressContext();
    response = responseMock.response;
    observedResponse = responseMock.result;

    // content-type should be undefined since it's not set in the response yet.
    expect(response.getHeader('content-type')).to.eql(undefined);
  }
});

function givenRequest(options?: ShotRequestOptions): Request {
  return stubExpressContext(options).request;
}

function givenStubbedContext() {
    contextStub = stubExpressContext();
  }
});

function givenRequest(options?: ShotRequestOptions): Request {
    return stubExpressContext(options).request;
  }

}
        }

        class CustomLogger implements Provider {
          value() {
            return (err: Error, statusCode: number, request: Request) => {
              lastLog = `${request.url} ${statusCode} ${err.message}`;
            };
          }
        }

        const app = new Application();
        app.component(CustomRestComponent);
        const server = await app.getServer(RestServer);
        const logError = await server.get(SequenceActions.LOG_ERROR);
        const expressContext = stubExpressContext({url: '/'});
        logError(new Error('test-error'), 400, expressContext.request);

        expect(lastLog).to.equal('/ 400 test-error');
      });
    });