Question

I’m new when it comes to using VS2010’s unit tests. I tried making a unit test that makes a call to the WCF hosted. The code looks like this:

...
[TestMethod]
public void TestMethod1()
{
   WcfClient client = new WcfClient("BasicHttpBinding_IWcf");
   client.GetDataCompleted += new EventHandler<GetDataCompletedEventArgs>(OnGetDataCompleted);
   client.GetDataAsync(arg1, arg2);
}

void OnGetDataCompleted(object sender, GetDataCompletedEventArgs e)
{
   Assert.IfNull(e.Error);
}

...

It seems like it’s never started or completed when I run it. I was thinking of adding this to a load test. Am I missing anything to test async calls to the WCF? I’ve heard of WCF Load Test in codeplex but I’ll leave that for another time.

a variation to peer’s answer: http://justgeeks.blogspot.com/2010/05/unit-testing-asynchronous-calls-in.html

Answer 1

The following code will test you async method, you have to wait in you main thead and do the asserts there:

[TestMethod]
public void TestMethod1()
{
  WcfClient client = new WcfClient("BasicHttpBinding_IWcf");

  AutoResetEvent waitHandle = new AutoResetEvent(false); 

  GetDataCompletedEventArgs args = null;
  client.GetDataCompleted = (s, e) => {
    args = e.Error;
    waitHandle.Set(); 
  };

  // call the async method
  client.GetDataAsync(arg1, arg2);

  // Wait until the event handler is invoked
  if (!waitHandle.WaitOne(5000, false))  
  {  
    Assert.Fail("Test timed out.");  
  }  

  Assert.IfNull(args.Error);
}