bpo-24234: implement complex.__complex__ (GH-27887)

Co-authored-by: Dong-hee Na <donghee.na92@gmail.com>

3 files changed, 14 insertions, 2 deletions

diff --git a/Lib/test/test_complex.py b/Lib/test/test_complex.py
index abd7e39..1cd025e 100644
--- a/Lib/test/test_complex.py
+++ b/Lib/test/test_complex.py
@@ -499,6 +499,18 @@ class ComplexTest(unittest.TestCase):
             self.assertEqual(complex(complex1(1j)), 2j)
         self.assertRaises(TypeError, complex, complex2(1j))
 
+    def test___complex__(self):
+        z = 3 + 4j
+        self.assertEqual(z.__complex__(), z)
+        self.assertEqual(type(z.__complex__()), complex)
+
+        class complex_subclass(complex):
+            pass
+
+        z = complex_subclass(3 + 4j)
+        self.assertEqual(z.__complex__(), 3 + 4j)
+        self.assertEqual(type(z.__complex__()), complex)
+
     @support.requires_IEEE_754
     def test_constructor_special_numbers(self):
         class complex2(complex):
diff --git a/Lib/test/test_doctest.py b/Lib/test/test_doctest.py
index 8f761d7..571dc78 100644
--- a/Lib/test/test_doctest.py
+++ b/Lib/test/test_doctest.py
@@ -668,7 +668,7 @@ plain ol' Python and is guaranteed to be available.
 
     >>> import builtins
     >>> tests = doctest.DocTestFinder().find(builtins)
-    >>> 816 < len(tests) < 836 # approximate number of objects with docstrings
+    >>> 820 < len(tests) < 840 # approximate number of objects with docstrings
     True
     >>> real_tests = [t for t in tests if len(t.examples) > 0]
     >>> len(real_tests) # objects that actually have doctests
diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
index 3bd5894..84521ee 100644
--- a/Lib/test/test_typing.py
+++ b/Lib/test/test_typing.py
@@ -1533,11 +1533,11 @@ class ProtocolTests(BaseTestCase):
 
     def test_supports_complex(self):
 
-        # Note: complex itself doesn't have __complex__.
         class C:
             def __complex__(self):
                 return 0j
 
+        self.assertIsSubclass(complex, typing.SupportsComplex)
         self.assertIsSubclass(C, typing.SupportsComplex)
         self.assertNotIsSubclass(str, typing.SupportsComplex)