Properly initialize instance

graphenecommon/instance.py

@@ -19,7 +19,9 @@ class AbstractBlockchainInstanceProvider:
     """
 
     def __init__(self, *args, **kwargs):
-        pass
+        self._blockchain = None
+        if kwargs.get("blockchain_instance"):
+            self._blockchain = kwargs["blockchain_instance"]
 
     @classmethod
     def inject(slf, cls):
@@ -47,7 +49,10 @@ def define_classes(self):
 
     @property
     def blockchain(self):
-        return self.shared_blockchain_instance()
+        if hasattr(self, "_blockchain") and self._blockchain:
+            return self._blockchain
+        else:
+            return self.shared_blockchain_instance()
 
     @property
     def chain(self):

graphenecommon/transactionbuilder.py

@@ -42,6 +42,7 @@ def __init__(
         assert self.operation_class
         assert self.operations
         assert self.account_class
+        AbstractBlockchainInstanceProvider.__init__(self, *args, **kwargs)
 
         self.set_expiration(proposal_expiration or 2 * 24 * 60 * 60)
         self.set_review(proposal_review)
@@ -141,6 +142,7 @@ def __init__(self, tx={}, proposer=None, **kwargs):
         assert self.publickey_class
         assert self.signed_transaction_class
         assert self.amount_class
+        AbstractBlockchainInstanceProvider.__init__(self, **kwargs)
 
         self.clear()
         if tx and isinstance(tx, dict):