public void UpdateRequiredTest()
{
var current = new Twin();
current.Tags["x"] = 1;
current.Properties.Desired["y"] = "one";
var existing = new Twin();
existing.Tags["x"] = 1;
existing.Properties.Desired["y"] = "one";
Assert.False(current.UpdateRequired(existing));
existing.Properties.Reported["z"] = DateTime.Now;
Assert.False(current.UpdateRequired(existing));
existing.Tags["x"] = 2;
Assert.True(current.UpdateRequired(existing));
existing.Tags["x"] = current.Tags["x"];
existing.Properties.Desired["y"] = "two";
Assert.True(current.UpdateRequired(existing));
existing.Properties.Desired["y"] = current.Properties.Desired["y"];
existing.Tags["xx"] = 3;
Assert.True(current.UpdateRequired(existing));
}