test: add None rejection tests for all entry points

Verify None raises TypeError for one-shot functions, constructors
(both positional and keyword), and update().

Author: ifduyue

tests/test_hashlib_compat.py

@@ -31,6 +31,9 @@ def test_str_rejected(self):
                 with self.assertRaisesRegex(TypeError,
                         'Strings must be encoded before hashing'):
                     fn(data='hello')
+                # None
+                with self.assertRaises(TypeError):
+                    fn(None)
 
     def test_str_rejected_constructor(self):
         for algo in ('xxh32', 'xxh64', 'xxh3_64', 'xxh3_128'):
@@ -43,6 +46,11 @@ def test_str_rejected_constructor(self):
             with self.assertRaisesRegex(TypeError,
                     'Strings must be encoded before hashing'):
                 cls(data='hello')
+            # None
+            with self.assertRaises(TypeError):
+                cls(None)
+            with self.assertRaises(TypeError):
+                cls(data=None)
 
     def test_str_rejected_update(self):
         for algo in ('xxh32', 'xxh64', 'xxh3_64', 'xxh3_128'):
@@ -53,6 +61,9 @@ def test_str_rejected_update(self):
             # also test that bytes work after
             obj.update(b'hello')
             self.assertIsInstance(obj.intdigest(), int)
+            # None
+            with self.assertRaises(TypeError):
+                obj.update(None)
 
     # ── data keyword ───────────────────────────────────────────────