Make test_is_nullish less numpy specific

Author: Cito

README.md

@@ -16,7 +16,7 @@ The current version 3.0.0a2 of GraphQL-core is up-to-date
 with GraphQL.js version 14.4.2.
 
 All parts of the API are covered by an extensive test suite
-of currently 1965 unit tests.
+of currently 1966 unit tests.
 
 
 ## Documentation

src/graphql/pyutils/is_finite.py

@@ -1,5 +1,5 @@
-from typing import Any
 from math import isfinite
+from typing import Any
 
 __all__ = ["is_finite"]
 

src/graphql/pyutils/is_integer.py

@@ -1,5 +1,5 @@
-from typing import Any
 from math import isfinite
+from typing import Any
 
 __all__ = ["is_integer"]
 

src/graphql/pyutils/is_nullish.py

@@ -1,4 +1,4 @@
-import math
+from math import isnan
 from typing import Any
 
 from ..error import INVALID
@@ -9,7 +9,5 @@
 def is_nullish(value: Any) -> bool:
     """Return true if a value is null, undefined, or NaN."""
     return (
-        value is None
-        or value is INVALID
-        or (isinstance(value, float) and math.isnan(value))
+        value is None or value is INVALID or (isinstance(value, float) and isnan(value))
     )

tests/pyutils/test_is_nullish.py

@@ -44,7 +44,22 @@ def undefined_is_nullish():
         assert is_nullish(INVALID) is True
 
     def nan_is_nullish():
-        assert is_nullish(nan)
+        assert is_nullish(nan) is True
 
-    def numpy_arrays_are_not_nullish():
-        assert is_nullish(FakeNumpyArray()) is False
+    def irreflexive_objects_are_not_nullish():
+        # Numpy arrays operate element-wise and the comparison operator returns arrays.
+        # Similar to math.nan, they are therefore not equal to themselves. However, we
+        # only want math.nan to be considered nullish, not values like numpy arrays.
+
+        class IrreflexiveValue:
+            def __eq__(self, other):
+                return False
+
+            def __bool__(self):
+                return False
+
+        value = IrreflexiveValue()
+        assert value != value
+        assert not value
+
+        assert is_nullish(value) is False