test: address __eq__ checking [APE-1178]

src/ape/api/address.py

@@ -57,7 +57,8 @@ def __eq__(self, other: object) -> bool:
         try:
             return convert(self, AddressType) == convert(other, AddressType)
         except ConversionError:
-            return False
+            # Check other __eq__
+            return NotImplemented
 
     def __dir__(self) -> List[str]:
         """

tests/functional/test_address.py

@@ -0,0 +1,24 @@
+import pytest
+
+from ape.api.address import BaseAddress
+from ape.types import AddressType
+
+
+@pytest.fixture
+def custom_address(zero_address):
+    class MyAddress(BaseAddress):
+        @property
+        def address(self) -> AddressType:
+            return zero_address
+
+    return MyAddress()
+
+
+def test_eq(zero_address, custom_address):
+    assert custom_address == zero_address
+    assert zero_address == custom_address
+
+
+def test_contains_in_list(zero_address, custom_address):
+    assert zero_address in [custom_address]
+    assert custom_address in [zero_address]