Replacing modules with dagger component builder

App.java

# In App class
public void onCreate() {
        applicationComponent = initializeAppComponentBuilder().build();
        applicationComponent.inject(this);
}

protected DaggerAppComponent.Builder initializeAppComponentBuilder() {
        return DaggerAppComponent.builder()
                .applicationModule(new ApplicationModule(this))
                .networkModule(new RealNetworkModule())
                .databaseModule(new DatabaseModule())
                .networkModule(new MockNetworkModule())
                .picassoModule(new PicassoModule())
                .androidModule(new AndroidModule())
                .etc();             
}
                
                
                
# And in test app you can replace only those modules that has to be replaced with fake ones

public class TestsApp extends App {

protected DaggerAppComponent.Builder initializeAppComponentBuilder() {
        return super.initializeAppComponentBuilder()
                .networkModule(new MockNetworkModule());
                // and the rest of "real" modules is already provided   
        }
}