TestSubscriber.AssertionChain that will make assertions against all of the events that have been recordedMatcher that matches a Throwable with a cause that matches a given matcherMatcher that matches a Throwable with a message that matches a given matcherSubscriber that records all events so that assertions can be made against them for testing purposes
TestSubscriber is entirely thread safe and makes no assumptions about the Observable contractTestSubscriber and make assertions against each event in the order received