further test refinements.

gpshead · Feb 12, 2024 · 5099616 · 5099616
1 parent 0302840
commit 5099616
Showing 1 changed file with 13 additions and 4 deletions.
diff --git a/Lib/test/test_capi/test_long.py b/Lib/test/test_capi/test_long.py
@@ -453,12 +453,21 @@ def test_long_asnativebytes(self):
             (-(2**256-1), 33),
         ]:
             with self.subTest(f"sizeof-{v:X}"):
-                buffer = bytearray(1)
+                buffer = bytearray(b"\x5a")
                 self.assertEqual(expect, asnativebytes(v, buffer, 0, -1),
-                    "PyLong_AsNativeBytes(v, NULL, 0, -1)")
+                    "PyLong_AsNativeBytes(v, <unknown>, 0, -1)")
                 # Also check via the __index__ path
                 self.assertEqual(expect, asnativebytes(Index(v), buffer, 0, -1),
-                    "PyLong_AsNativeBytes(Index(v), NULL, 0, -1)")
+                    "PyLong_AsNativeBytes(Index(v), <unknown>, 0, -1)")
+
+        # Test that we populate n=2 bytes but do not overwrite more.
+        buffer = bytearray(b"\x99"*3)
+        self.assertEqual(2, asnativebytes(4, buffer, 2, 0),  # BE
+            "PyLong_AsNativeBytes(v, <3 byte buffer>, 2, 0)  // BE")
+        self.assertEqual(buffer, b"\x00\x04\x99")
+        self.assertEqual(2, asnativebytes(4, buffer, 2, 1),  # LE
+            "PyLong_AsNativeBytes(v, <3 byte buffer>, 2, 1)  // LE")
+        self.assertEqual(buffer, b"\x04\x00\x99")
 
         # We request as many bytes as `expect_be` contains, and always check
         # the result (both big and little endian). We check the return value
@@ -512,7 +521,7 @@ def test_long_asnativebytes(self):
                 n = len(expect_be)
                 # Fill the buffer with dummy data to ensure all bytes
                 # are overwritten.
-                buffer = bytearray(b'\xa5'*n)
+                buffer = bytearray(b"\xa5"*n)
                 expect_le = expect_be[::-1]
 
                 self.assertEqual(expect_n, asnativebytes(v, buffer, n, 0),