Billing in Android app, bad answer -1002

I am learning how to implement in-app billing based on this article - http://www.techotopia.com/index.php/Integrating_Google_Play_In-app_Billing_into_an_Android_Application_%E2%80%93_A_Tutorial

Every time I try to run this app in DEBUG mode I got an error that says "Google Play Store" crashed and my logs say

E / InAppBilling: Billing error in application: null data as a result of IAB action.

Error: error while purchasing: labResult: null data in IAB result (response: -1002: wrong response received)

Caused by: java.lang.NullPointerException: Attempting to call interface method 'android.os.Bundle com.android.vending.billing.IInAppBillingService.getBuyIntent (int, java.lang.String, java.lang.String, java.lang.String, java.lang.String) 'on a null object reference

HERE I GOT MY ERROR

Also I successfully run a Google sample called Trivial Drive in RELEASE mode, but when I replace the real SKU with a test one (for example android.test.purchased) and run the app in DEBUG mode I got the same error.

Full Activity Code

public class InAppBillingActivity extends AppCompatActivity {
private Button clickButton;
private Button buyButton;

private static final String TAG = "InAppBilling";
IabHelper mHelper;

static final String ITEM_SKU = "android.test.purchased";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.billing_activity);
    buyButton = (Button)findViewById(R.id.buyButton);
    clickButton = (Button)findViewById(R.id.clickButton);
    clickButton.setEnabled(false);

    String base64EncodedPublicKey = "HERE IS MY KEY FROM DEVELOPER CONSOLE";
    mHelper = new IabHelper(this, base64EncodedPublicKey);

    mHelper.startSetup(new IabHelper.OnIabSetupFinishedListener() {
        @Override
        public void onIabSetupFinished(IabResult result) {
            if (!result.isSuccess()) {
                Log.d(TAG, "In-app Billing setup failed:" + result);
            } else {
                Log.d(TAG, "In-app Billing is set up OK");
                mHelper.enableDebugLogging(true, TAG);
            }
        }
    });
}

public void buttonClicked (View view) {
    clickButton.setEnabled(false);
    buyButton.setEnabled(true);
}

IabHelper.OnIabPurchaseFinishedListener mPurchaseFinishedListener = new IabHelper.OnIabPurchaseFinishedListener() {
    public void onIabPurchaseFinished(IabResult result, Purchase purchase) {
        if (result.isFailure()) {// Handle error
            return;
        }
        else if (purchase.getSku().equals(ITEM_SKU)) {
            consumeItem();
            buyButton.setEnabled(false);
        }
    }
};

public void buyClick(View view) {
    mHelper.launchPurchaseFlow(this, ITEM_SKU, 10001, mPurchaseFinishedListener, "mypurchasetoken");
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (!mHelper.handleActivityResult(requestCode,
            resultCode, data)) {
        super.onActivityResult(requestCode, resultCode, data);
    }
}

public void consumeItem() {
    mHelper.queryInventoryAsync(mReceivedInventoryListener);
}

IabHelper.QueryInventoryFinishedListener mReceivedInventoryListener = new IabHelper.QueryInventoryFinishedListener() {
    public void onQueryInventoryFinished(IabResult result, Inventory inventory) {
        if (result.isFailure()) {
            // Handle failure
        } else {
            mHelper.consumeAsync(inventory.getPurchase(ITEM_SKU), mConsumeFinishedListener);
        }
    }
};

IabHelper.OnConsumeFinishedListener mConsumeFinishedListener = new IabHelper.OnConsumeFinishedListener() {
    public void onConsumeFinished(Purchase purchase, IabResult result) {
        if (result.isSuccess()) {
            clickButton.setEnabled(true);
        } else {
            // handle error
        }
    }
};

@Override
public void onDestroy() {
    super.onDestroy();
    if (mHelper != null) mHelper.dispose();
    mHelper = null;
}