Add padding back to StrictByteStringEncoder

Author: kclowes

web3/_utils/abi.py

@@ -253,7 +253,15 @@ def validate(self):
 
     def encode(self, value):
         normalized_value = self.validate_value(value)
-        return self.encode_fn(normalized_value)
+
+        base_encoded_value = self.encode_fn(normalized_value)
+
+        if self.is_big_endian:
+            padded_encoded_value = base_encoded_value.rjust(32, b'\x00')
+        else:
+            padded_encoded_value = base_encoded_value.ljust(32, b'\x00')
+
+        return padded_encoded_value
 
     def validate_value(self, value):
         if not is_bytes(value) and not is_text(value):