gistfile1.txt

// Object which should be returned as out parameter from another mock object
var mockedObject = MockRepository.GenerateMock<IRealTimeData>();
mockedObject.Expect(x => x.HeatValue).Return(30);

// Mock object which has method GetRealTimeData(out var ...) with out params as IRealTimeData
serverMockObject.Expect(x => x.GetRealTimeData(out _)).OutRef(mockedObject).Return(true);

var actualValue  = serice.GetHeatValue();
// Inside the implementation of above method, see below.

private void GetRealTimeData(out IRealTimeData ealTimeData)
{
  //...
}

public double GetHeat()
{
  GetRealTimeData(out var realTimeData); // At this statement the object realTimeData contains the data that I am mocking from unit test
  if(realTimeData != null)
     var absoluteHeat = realTimeData.HeatValue; // At this statement the object realTimeData resets the value of all properties.
     
     // if I try to skip the null condition and directly execute line no. #20 then I am able to get the value that I am setting from 
     // unit test.
}