Inapp billing problem with getPurchaseInformation()

I followed this tut, and app is getting null for mS开发者_JAVA技巧ervice and mContext in getPurchaseInformation().

And how to test inapp billing before publishing. Is it the only way to upload apk file as unpublished draft application and test it,

Looking forward for valuable advices.

Thanks in advance.

No, you have to use test library, see : http://developer.android.com/guide/market/billing/billing_testing.html