I am not able to clear the test purchase using the product ID= "android.test.purchased".
However, if i use google app billing sample app procedure, i am able to do it by this command "adb shell pm clear com.android.vending", but its not working this library.
bp.consumePurchase("android.test.purchased");
Just in case you haven't got your answer yet. I usually clear the purchase state using this command: adb shell pm clear com.android.vending
Most helpful comment
bp.consumePurchase("android.test.purchased");