Fix Message equality comparison (#513)

src/betterproto/__init__.py

@@ -651,7 +651,7 @@ def __raw_get(self, name: str) -> Any:
 
     def __eq__(self, other) -> bool:
         if type(self) is not type(other):
-            return False
+            return NotImplemented
 
         for field_name in self._betterproto.meta_by_field_name:
             self_val = self.__raw_get(field_name)

tests/test_features.py

@@ -18,6 +18,7 @@
     List,
     Optional,
 )
+from unittest.mock import ANY
 
 import pytest
 
@@ -727,3 +728,15 @@ class Spam(betterproto.Message):
     assert not Spam().is_set("bar")
     assert Spam(foo=True).is_set("foo")
     assert Spam(foo=True, bar=0).is_set("bar")
+
+
+def test_equality_comparison():
+    from tests.output_betterproto.bool import Test as TestMessage
+
+    msg = TestMessage(value=True)
+
+    assert msg == msg
+    assert msg == ANY
+    assert msg == TestMessage(value=True)
+    assert msg != 1
+    assert msg != TestMessage(value=False)