Question

What is the best way to test this property:

  public string ThreadId {
        get { return _threadId; }
        set {
            _threadId = value;
            NotifyPropertyChanged();
        }
    }

I have this test so far:

    [Fact]
    public void ThreadIdTest() {
        compassLogData.ThreadId = "[11]";
        const string expected = "[11]";
        string actual = compassLogData.ThreadId;
        Assert.Equal(expected, actual);
    }

but i need a away to test NotifyPropertyChanged() which is used to
update the UI.

Answer 1

A simple way would be to do this:

var notified = false;
compassLogData.PropertyChanged += (s, e) =>
{
    if(e.PropertyName == "ThreadId")
        notified = true;
};

compassLogData.ThreadId = "[11]";
Assert.True(notified);