async test helpers

    func asyncTestWithAssertBlock(block: (XCTestExpectation)->()) {
        let expectation = self.expectationWithDescription("test expectation")
        block(expectation)
        waitForExpectationsWithTimeout(3, handler: nil)
    }
    
    func notifTestWithAssertBlock(block: ()-> Void) {
        expectationForNotification(Blurbs.BlurbsReadyNotification, object: nil) { _ in
            block()
            return true
        }
        waitForExpectationsWithTimeout(3, handler: nil)
    }
    
    
    
    usage
    
    func testPrepareSetPrepareFlagToTrue() {
        subject.prepareAndNotify()
        
        notifTestWithAssertBlock {
           XCTAssertTrue(Blurbs.didCalledPrepare)
        }
    }