schema validates that create txes only have 1 input and that it has no fulfills

bigchaindb/common/schema/transaction_create.yaml

@@ -1,17 +1,28 @@
 ---
 "$schema": "http://json-schema.org/draft-04/schema#"
 type: object
-title: Transaction Schema - CREATE/GENESIS specific properties
+title: Transaction Schema - CREATE/GENESIS specific constraints
 required:
 - asset
+- inputs
 properties:
   asset:
     additionalProperties: false
     properties:
       data:
-        description: |
-          User provided metadata associated with the asset. May also be ``null``.
         anyOf:
         - type: object
           additionalProperties: true
         - type: 'null'
+  inputs:
+    type: array
+    title: "Transaction inputs"
+    maxItems: 1
+    minItems: 1
+    items:
+      type: "object"
+      required:
+      - fulfills
+      properties:
+        fulfills:
+            type: "null"

tests/common/schema/test_transaction_schema.py

@@ -32,8 +32,6 @@ def test_validate_fails_metadata_empty_dict(create_tx):
 
 
 def test_transfer_asset_schema(signed_transfer_tx):
-    from bigchaindb.common.schema import (SchemaValidationError,
-                                          validate_transaction_schema)
     tx = signed_transfer_tx.to_dict()
     validate_transaction_schema(tx)
     tx['asset']['data'] = {}
@@ -43,3 +41,20 @@ def test_transfer_asset_schema(signed_transfer_tx):
     tx['asset']['id'] = 'b' * 63
     with raises(SchemaValidationError):
         validate_transaction_schema(tx)
+
+
+def test_create_single_input(create_tx):
+    tx = create_tx.to_dict()
+    tx['inputs'] += tx['inputs']
+    with raises(SchemaValidationError):
+        validate_transaction_schema(tx)
+    tx['inputs'] = []
+    with raises(SchemaValidationError):
+        validate_transaction_schema(tx)
+
+
+def test_create_tx_no_fulfills(create_tx):
+    tx = create_tx.to_dict()
+    tx['inputs'][0]['fulfills'] = {'tx': 'a' * 64, 'output': 0}
+    with raises(SchemaValidationError):
+        validate_transaction_schema(tx)