diff --git a/bigchaindb/common/crypto.py b/bigchaindb/common/crypto.py
index e440f81d..82b15136 100644
--- a/bigchaindb/common/crypto.py
+++ b/bigchaindb/common/crypto.py
@@ -14,5 +14,6 @@ def generate_key_pair():
     private_key, public_key = crypto.ed25519_generate_key_pair()
     return private_key.decode(), public_key.decode()
 
+
 SigningKey = crypto.Ed25519SigningKey
 VerifyingKey = crypto.Ed25519VerifyingKey
diff --git a/bigchaindb/common/exceptions.py b/bigchaindb/common/exceptions.py
index 2e1dc670..72e300fd 100644
--- a/bigchaindb/common/exceptions.py
+++ b/bigchaindb/common/exceptions.py
@@ -69,9 +69,9 @@ class CyclicBlockchainError(Exception):
     """Raised when there is a cycle in the blockchain"""
 
 
-class FulfillmentNotInValidBlock(Exception):
-    """Raised when a transaction depends on an invalid or undecided
-    fulfillment"""
+class TransactionNotInValidBlock(Exception):
+    """Raised when a transfer transaction is attempting to fulfill the
+    conditions of a transaction that is in an invalid or undecided block"""
 
 
 class AssetIdMismatch(Exception):
diff --git a/bigchaindb/core.py b/bigchaindb/core.py
index 45e9be80..8045e6ba 100644
--- a/bigchaindb/core.py
+++ b/bigchaindb/core.py
@@ -186,7 +186,7 @@ class Bigchain(object):
                 exceptions.TransactionDoesNotExist,
                 exceptions.TransactionOwnerError, exceptions.DoubleSpend,
                 exceptions.InvalidHash, exceptions.InvalidSignature,
-                exceptions.FulfillmentNotInValidBlock, exceptions.AmountError):
+                exceptions.TransactionNotInValidBlock, exceptions.AmountError):
             return False
 
     def get_block(self, block_id, include_status=False):
diff --git a/bigchaindb/models.py b/bigchaindb/models.py
index efee0502..cd472ed6 100644
--- a/bigchaindb/models.py
+++ b/bigchaindb/models.py
@@ -2,7 +2,7 @@ from bigchaindb.common.crypto import hash_data, VerifyingKey, SigningKey
 from bigchaindb.common.exceptions import (InvalidHash, InvalidSignature,
                                           OperationError, DoubleSpend,
                                           TransactionDoesNotExist,
-                                          FulfillmentNotInValidBlock,
+                                          TransactionNotInValidBlock,
                                           AssetIdMismatch, AmountError)
 from bigchaindb.common.transaction import Transaction, Asset
 from bigchaindb.common.util import gen_timestamp, serialize
@@ -24,6 +24,8 @@ class Transaction(Transaction):
             OperationError: if the transaction operation is not supported
             TransactionDoesNotExist: if the input of the transaction is not
                                      found
+            TransactionNotInValidBlock: if the input of the transaction is not
+                                        in a valid block
             TransactionOwnerError: if the new transaction is using an input it
                                    doesn't own
             DoubleSpend: if the transaction is a double spend
@@ -62,7 +64,7 @@ class Transaction(Transaction):
                                                   .format(input_txid))
 
                 if status != bigchain.TX_VALID:
-                    raise FulfillmentNotInValidBlock(
+                    raise TransactionNotInValidBlock(
                         'input `{}` does not exist in a valid block'.format(
                             input_txid))
 
diff --git a/bigchaindb/web/views/transactions.py b/bigchaindb/web/views/transactions.py
index 8780fda8..c529b6b3 100644
--- a/bigchaindb/web/views/transactions.py
+++ b/bigchaindb/web/views/transactions.py
@@ -111,6 +111,7 @@ class TransactionListApi(Resource):
 
         return tx
 
+
 transaction_api.add_resource(TransactionApi,
                              '/transactions/<string:tx_id>',
                              strict_slashes=False)
diff --git a/tests/db/test_bigchain_api.py b/tests/db/test_bigchain_api.py
index 247a31b4..144bfeed 100644
--- a/tests/db/test_bigchain_api.py
+++ b/tests/db/test_bigchain_api.py
@@ -701,9 +701,9 @@ class TestTransactionValidation(object):
         assert transfer_tx == b.validate_transaction(transfer_tx)
 
     @pytest.mark.usefixtures('inputs')
-    def test_fulfillment_not_in_valid_block(self, b, user_vk, user_sk):
+    def test_transaction_not_in_valid_block(self, b, user_vk, user_sk):
         from bigchaindb.models import Transaction
-        from bigchaindb.common.exceptions import FulfillmentNotInValidBlock
+        from bigchaindb.common.exceptions import TransactionNotInValidBlock
 
         input_tx = b.get_owned_ids(user_vk).pop()
         input_tx = b.get_transaction(input_tx.txid)
@@ -726,7 +726,7 @@ class TestTransactionValidation(object):
                                           transfer_tx.asset)
         tx_invalid = tx_invalid.sign([user_sk])
 
-        with pytest.raises(FulfillmentNotInValidBlock):
+        with pytest.raises(TransactionNotInValidBlock):
             b.validate_transaction(tx_invalid)