android - How to shadow singleton with Robolectic? -

i have such singleton:

public class singletona{        private singletona instance = null;        private singletona(){       }        public static singletona getinstance(){           return instance ;       }        public static void init(){            system.loadlibrary("alib");            instance = new singletona();       }        ......       other methods } 

as can see, before use , have call singletona.init().but robolectric can not load .so file. want write shadowsingletona replace it, don't know how do.because variable instance private. can 1 help? besides, class singletona third part library can not modification it.

another common way deal dependencies abstract them make them interchangeable , testable.

so assume have great library next api:

class libraryname {     public static somesinglethon getinstance(); } 

first, create abstraction:

public class librarygenericpurpose {    public void dosomething(@nonnull string nameofthing) {       libraryname.getinstance().dosomething(new event(nameofthing));    } } 

first note method not static, have add dependency in places calling static methods library. handy have interface such thing.

and change place use from:

class someclass {     public void somemethod() {         libraryname.getinstance().dosomething(new event(nameofthing));     } } 

to:

class someclass {     @nonnull private librarygenericpurpose library;      public someclass(@nonnull librarygenericpurpose library) {         this.library = library;     }      public void somemethod() {         library.dosomething("great!");     } } 

and if don't have control on class life cycle activity or fragment have learn new ways how inject dependencies there.

finally, in tests, don't need use robolectric someclass @ all. , quite these classes librarygenericpurpose not testable on jvm (even robolectric) , quite hard or impossible test in instrumental tests.