java - RxJava: How to unit test that an Observable is observed on and subscribed on the right scheduler? -

i have following scenario:

interface itemsrepository {     observable<list<item>> getitems(); }  class getitems {     private scheduler ioscheduler;     private scheduler mainscheduler;     private itemsrepository itemsrepository;     getitems(scheduler ioscheduler,               scheduler mainscheduler,               itemsrepository itemsrepository) {         this.ioscheduler = ioscheduler;         this.mainscheduler = mainscheduler;         this.itemsrepository = itemsrepository;     }      observable execute(susbscriber subscriber) {         return itemsrepository.getitems()                               .subscribeon(ioscheduler)                               .observeon(mainscheduler)                               .subscribe(subscriber);     } } 

now want unit test subscribeon , observeon called using correct schedulers.

the way did writing 2 unit tests follows:

@runwith(mockitojunitrunner.class) class getitemstest {     private getitems getitems;     private testscheduler ioscheduler = schedulers.test();     private testscheduler mainscheduler = schedulers.test();     private testsubscriber<list<item>> subscriber = new testsubscriber();     private list<item> items;      @mock     private itemsrepository itemsrepository;      @before     private void setup() {         getitems = new getitems(ioscheduler, mainscheduler, itemsrepository);         items = anylistof(item.class);         given(itemsrepository.getitems()).willreturn(observable.just(items));         getitems.execute();     }      @test     public void should_subscribe_repository_on_the_io_scheduler throws exception {         subscriber.assertnovalues();          mainscheduler.triggeractions();          subscriber.assertnovalues();     }      @test     public void should_observe_repository_on_the_main_scheduler() throws exception {         subscriber.assertnovalues();          ioscheduler.triggeractions();         subscriber.assertnovalues();         mainscheduler.triggeractions();          subscriber.assertvalue(trendingdestinations);     }  } 

i wandering if there better solution. triggering actions in order (io first , main) not cover case accidentally use ioscheduler twice. also, second test doesn't defend using mainscheduler twice well. solution, while defending against right things, not readable , not tell reader how testing states in name of test method. using solution now, appreciate suggestions.