bpo-22273: Update ctypes to correctly handle arrays in small structur… (GH-15839)

1 files changed, 41 insertions, 0 deletions

diff --git a/Lib/ctypes/test/test_structures.py b/Lib/ctypes/test/test_structures.py
index fda1045..11c194b 100644
--- a/Lib/ctypes/test/test_structures.py
+++ b/Lib/ctypes/test/test_structures.py
@@ -477,6 +477,47 @@ class StructureTestCase(unittest.TestCase):
         self.assertEqual(s.first, got.first)
         self.assertEqual(s.second, got.second)
 
+    def test_array_in_struct(self):
+        # See bpo-22273
+
+        # These should mirror the structures in Modules/_ctypes/_ctypes_test.c
+        class Test2(Structure):
+            _fields_ = [
+                ('data', c_ubyte * 16),
+            ]
+
+        class Test3(Structure):
+            _fields_ = [
+                ('data', c_double * 2),
+            ]
+
+        s = Test2()
+        expected = 0
+        for i in range(16):
+            s.data[i] = i
+            expected += i
+        dll = CDLL(_ctypes_test.__file__)
+        func = dll._testfunc_array_in_struct1
+        func.restype = c_int
+        func.argtypes = (Test2,)
+        result = func(s)
+        self.assertEqual(result, expected)
+        # check the passed-in struct hasn't changed
+        for i in range(16):
+            self.assertEqual(s.data[i], i)
+
+        s = Test3()
+        s.data[0] = 3.14159
+        s.data[1] = 2.71828
+        expected = 3.14159 + 2.71828
+        func = dll._testfunc_array_in_struct2
+        func.restype = c_double
+        func.argtypes = (Test3,)
+        result = func(s)
+        self.assertEqual(result, expected)
+        # check the passed-in struct hasn't changed
+        self.assertEqual(s.data[0], 3.14159)
+        self.assertEqual(s.data[1], 2.71828)
 
 class PointerMemberTestCase(unittest.TestCase):