test(General): implement unit test for serializer

amqp/adapter/serializer.py

@@ -18,7 +18,7 @@ def bytes_to_long(b: bytes) -> int:
 def read_long(bis: BytesIO) -> int:
     try:
         return struct.unpack("q", bis.read(8))[0]
-    except IOError:
+    except struct.error:
         return 0
 
 
@@ -51,7 +51,10 @@ def csv_as_list(input_str: str) -> List[str]:
 
 
 def add_to_map(map_: Dict[str, List[str]], token: str) -> None:
-    eq_idx = token.index("=")
+    try:
+        eq_idx = token.index("=")
+    except ValueError:
+        eq_idx = -1  # set to -1 when not found
     if eq_idx > 0:
         key = token[:eq_idx]
         map_[key] = csv_as_list(token[eq_idx + 1 :])