public void Switch()
{
var s = new UnicastSubject <ICompletableSource>();
var cs1 = new CompletableSubject();
var cs2 = new CompletableSubject();
var cs3 = new CompletableSubject();
var to = s
.SwitchMap(v => v)
.Test();
to.AssertEmpty();
Assert.False(cs1.HasObserver());
Assert.False(cs2.HasObserver());
Assert.False(cs3.HasObserver());
s.OnNext(cs1);
Assert.True(cs1.HasObserver());
Assert.False(cs2.HasObserver());
Assert.False(cs3.HasObserver());
cs1.OnCompleted();
Assert.False(cs2.HasObserver());
Assert.False(cs3.HasObserver());
s.OnNext(cs2);
Assert.True(cs2.HasObserver());
Assert.False(cs3.HasObserver());
s.OnNext(cs3);
Assert.False(cs2.HasObserver());
Assert.True(cs3.HasObserver());
to.AssertEmpty();
s.OnCompleted();
to.AssertEmpty();
cs3.OnCompleted();
to.AssertResult();
}