Rule for junit testing so as to run RxJava code on the junit Thread of execution. Instantiate as field member on a junit test class: @rule public TrampolineSchedulerRule mTrampolineSchedulerRule = new TrampolineSchedulerRule();

TrampolineSchedulerRule.java

@Override
    public Statement apply(final Statement base, Description d) {
        return new Statement() {
            @Override
            public void evaluate() throws Throwable {

                RxJavaPlugins.setIoSchedulerHandler(scheduler -> Schedulers.trampoline());
                RxJavaPlugins.setComputationSchedulerHandler(scheduler -> Schedulers.trampoline());
                RxJavaPlugins.setNewThreadSchedulerHandler(scheduler -> Schedulers.trampoline());
                RxAndroidPlugins.setInitMainThreadSchedulerHandler(schedulerCallable -> Schedulers.trampoline());

                try {
                    base.evaluate();
                } finally {
                    RxJavaPlugins.reset();
                    RxAndroidPlugins.reset();
                }
            }
        };
    }