TST: fix regression in longdouble alias check on Windows

Author: pareshjoshij

src/numpy-stubs/@test/runtime/test_ctype_assumptions.py

@@ -23,36 +23,39 @@ def test_longlong_64(char: str) -> None:
     assert np.dtype(char).alignment == 8
 
 
-@pytest.mark.parametrize(
-    ("name_c", "name_expect"),
-    [
-        ("byte", "int8"),
-        ("short", "int16"),
-        ("intc", "int32"),
-        ("long", "int32" if WIN32 else f"int{SIZE_P}"),
-        ("intp", f"int{SIZE_P}"),
-    ],
-)
+# --- Integer Aliases ---
+_int_aliases = [
+    ("byte", "int8"),
+    ("short", "int16"),
+    ("intc", "int32"),
+    ("intp", f"int{SIZE_P}"),
+    # On Windows long is int32 (LLP64), on Linux it matches pointer size (LP64).
+    ("long", "int32" if WIN32 else f"int{SIZE_P}"),
+]
+
+
+@pytest.mark.parametrize(("name_c", "name_expect"), _int_aliases)
 def test_alias_integer(name_c: str, name_expect: str) -> None:
     signed_c: type[np.signedinteger] = getattr(np, name_c)
     signed_expect: type[np.signedinteger] = getattr(np, name_expect)
-    assert signed_c is signed_expect
+    assert np.dtype(signed_c) == np.dtype(signed_expect)
 
     unsigned_c: type[np.unsignedinteger] = getattr(np, f"u{name_c}")
     unsigned_expect: type[np.unsignedinteger] = getattr(np, f"u{name_expect}")
-    assert unsigned_c is unsigned_expect
-
-
-@pytest.mark.parametrize(
-    ("name_c", "name_expect"),
-    [
-        ("half", "float16"),
-        ("single", "float32"),
-        ("double", "float64"),
-        ("longdouble", "float96" if WIN32 else f"float{SIZE_P + 64}"),
-    ],
-)
+    assert np.dtype(unsigned_c) == np.dtype(unsigned_expect)
+
+
+# --- Floating Point Aliases ---
+_float_aliases = [
+    ("half", "float16"),
+    ("single", "float32"),
+    ("double", "float64"),
+    ("longdouble", np.dtype(np.longdouble).name),
+]
+
+
+@pytest.mark.parametrize(("name_c", "name_expect"), _float_aliases)
 def test_alias_floating(name_c: str, name_expect: str) -> None:
     floating_c: type[np.floating] = getattr(np, name_c)
     floating_expect: type[np.floating] = getattr(np, name_expect)
-    assert floating_c is floating_expect
+    assert np.dtype(floating_c) == np.dtype(floating_expect)