public void NotifyOnTemperatureChange_ShouldNotNotify(double triggerReading, double threshold, double sensitivityVariance, TemperatureChangeType changeType, ThresholdInfo result) { // Arrange // Set the reading before we request a notfication so it's not the first time _thermometer.SetReading(triggerReading); // Act var actualReading = default(ThresholdInfo); _thermometer.NotifyOnTemperatureChange(changeType, "Boiling", threshold, sensitivityVariance, (t) => { actualReading = t; }); _thermometer.SetReading(triggerReading); // Assert // Should be null and should not have been called Assert.AreEqual(result, actualReading); }