Added null check on registry in base encoder

Author: stefanmendoza

eth_abi/codec.py

@@ -30,6 +30,9 @@
 
 class BaseABICodecEncoder():
     def __init__(self, registry):
+        if registry is None:
+            raise ValueError("`registry` may not be None")
+        
         self._registry = registry
 
     def encode_single(self, typ: TypeStr, arg: Any) -> bytes:

tests/test_codec/test_base_abi_codec_encoder.py

@@ -0,0 +1,4 @@
+from eth_abi.codec import (
+    BaseABICodecEncoder,
+)
+