Test Double Code

// Test to add  - this should fail
[TestMethod]
public void CheckExternalTemperatureConverted(){
    Converter tc = new Converter();
    Assert.AreEqual(32.0, tc.ExternalToFahrenheit()); 
    }
// Class to add:
 public class ExternalTemperatureGetter {
      private Random random = new Random();
      public double GetTemperature(){
         double value = random.Next(99); 
         return value; 
        }
    } 

// Method to add to Converter:   

 ExternalTemperatureGetter etc = 
      new ExternalTemperatureGetter(); 
 public double ExternalToFahrenheit()
     {
     double temp = etc.GetTemperature();
     return ToFahrenheit(temp); 
     }