pyright: add aliasing test (#1063)

tests/dataclass_transform_example.py

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: MIT
 
 import attr
+import attrs
 
 
 @attr.define()
@@ -43,3 +44,14 @@ d2 = FrozenDefine("a")
 d2.a = "new"
 
 reveal_type(d2.a)  # noqa
+
+
+# Field-aliasing works
+@attrs.define
+class AliasedField:
+    _a: int = attrs.field(alias="_a")
+
+
+af = AliasedField(42)
+
+reveal_type(af.__init__)  # noqa

tests/test_pyright.py

@@ -75,9 +75,13 @@ def test_pyright_baseline():
             severity="information",
             message='Type of "d2.a" is "Literal[\'new\']"',
         ),
+        PyrightDiagnostic(
+            severity="information",
+            message='Type of "af.__init__" is "(_a: int) -> None"',
+        ),
     }
 
-    assert diagnostics == expected_diagnostics
+    assert expected_diagnostics == diagnostics
 
 
 def test_pyright_attrsinstance_compat(tmp_path):