android - How to test complex RxJava Observables -

i using rxjava in android project , i'm starting unit testing code.

i have following observable method i'm going test

private observable<boolean> changemystring (@nonnull string teststring) {     return oneclass         .dosth1(teststring)         .subscribeon(schedulers.io())         .observeon(androidschedulers.mainthread())         .flatmap(teststring2 -> observable.create(             subscriber -> {                 manager.setteststring2(teststring2);                 anotherclass                     .dosth2(teststring2)                     .subscribe(                         teststring3 -> {                             manager.setteststring3(teststring3);                             subscriber.onnext(success);                         },                         subscriber::onerror,                         subscriber::oncompleted                     );             }         )); 

oneclass.java dosth1(string teststring)

private observable<object> dosth1 (@nonnull string teststring) {     return observable.create(subscriber -> {         try {             teststring = "changedstring"             subscriber.onnext(teststring);             subscriber.oncompleted();         }         catch (exception e) {             subscriber.onerror(e);         }     }); } 

anotherclass.java dosth2(object someobject)

    public observable<string> dosth2 (@nonnull object someobject) {     return observable.create(subscriber -> {         string changetext = preferences.getstring(anystring, null); //preferences = sharedprefences         if (stringhelper.isempty(changetext)) {             subscriber.oncompleted();             return;         }         try {             string finishedstring = "we done! " + someobject.tostring();             subscriber.onnext(finishedstring);             subscriber.oncompleted();         }         catch (exception e) {             subscriber.onerror(e);         }     }); } 

my test case looks following:

testsubscriber<boolean> testsubscriber = new testsubscriber<>(); classtotest.changemystring("teststring").subscribe(testsubscriber); 

when debug code it's not reaching part here:

... .flatmap(teststring2 -> observable.create(         subscriber -> {             manager.setteststring2(teststring2);             anotherclass                 .dosth2(teststring2)                 .subscribe(                     teststring3 -> {                         manager.setteststring3(teststring3);                         subscriber.onnext(success);                     },                     subscriber::onerror,                     subscriber::oncompleted                 );         }     )); 

how can write unit test case? can't figure out, why it's not working...

thanks guys!

alban

instead of using directly schedulers, may want inject , use testscheduler instead. allow controle executions. (as unit test, may complicated deal others schedulers)

for more information on testscheduler : how use testscheduler in rxjava

 class yourclass {          private final scheduler ioscheduler;         private final scheduler uischeduler;          public yourclass(scheduler ioscheduler, scheduler uischeduler) {                this.ioscheduler = ioscheduler;                this.uischeduler = uischeduler;         }          private observable<boolean> changemystring (@nonnull string teststring) {          return oneclass.dosth1(teststring)                         .subscribeon(ioscheduler)                         .observeon(uischeduler)                         .doonnext(str -> manager.setteststring2(str))                         .flatmap(teststring2 -> anotherclass                         .dosth2(teststring2))                         .doonnext(str -> manager.setstring3(str));          }  } 

then in test, can inject testscheduler instead :

   @test    public void example() {           testscheduler ui = new testscheduler();           testscheduler io = new testscheduler();          yourclass hello = new yourclass(io, ui);            testsubscriber subscriber = new testsubscriber();            hello.changemystring("stuff").subscribe(subscriber);            io.advancebytime(2, seconds);          ui.advancebytime(2, seconds);           // perform check on subscriber here     } 

please note refactored code should avoid nested subscription.