diff -r ffe091ebd5de Lib/test/test_int.py
--- a/Lib/test/test_int.py	Mon Dec 24 13:15:43 2012 +0200
+++ b/Lib/test/test_int.py	Mon Dec 24 21:43:43 2012 +0200
@@ -1,6 +1,7 @@
 import sys
 
 import unittest
+from test import support
 from test.support import run_unittest
 
 L = [
@@ -74,8 +75,6 @@
         self.assertEqual(x >> 1, x//2)
 
         self.assertRaises(ValueError, int, '123\0')
-        self.assertRaises(ValueError, int, '53', 40)
-
         # SF bug 1545497: embedded NULs were not detected with
         # explicit base
         self.assertRaises(ValueError, int, '123\0', 10)
@@ -85,7 +84,8 @@
         self.assertIsInstance(x, int)
 
 
-        self.assertRaises(TypeError, int, 1, 12)
+        self.assertRaises(TypeError, int, 1, 10)
+        self.assertRaises(TypeError, int, 1, 0)
 
         self.assertEqual(int('0o123', 0), 83)
         self.assertEqual(int('0x123', 16), 291)
@@ -100,10 +100,6 @@
         self.assertRaises(ValueError, int, "0b", 2)
         self.assertRaises(ValueError, int, "0b", 0)
 
-        # Bug #3236: Return small longs from PyLong_FromString
-        self.assertTrue(int("10") is 10)
-        self.assertTrue(int("-1") is -1)
-
         # SF bug 1334662: int(string, base) wrong answers
         # Various representations of 2**32 evaluated to 0
         # rather than 2**32 in previous versions
@@ -221,6 +217,67 @@
         self.assertEqual(int('2br45qc', 35), 4294967297)
         self.assertEqual(int('1z141z5', 36), 4294967297)
 
+    @support.cpython_only
+    def test_small_ints(self):
+        # Bug #3236: Return small longs from PyLong_FromString
+        self.assertIs(int("10"), 10)
+        self.assertIs(int("-1"), -1)
+
+    def test_no_args(self):
+        self.assertEqual(int(), 0)
+
+    def test_keyword_args(self):
+        # Test invoking int() using keyword arguments.
+        self.assertEqual(int(x=1.2), 1)
+        self.assertEqual(int('100', base=2), 4)
+        self.assertEqual(int(x='100', base=2), 4)
+        self.assertRaises(TypeError, int, base=10)
+        self.assertRaises(TypeError, int, base=0)
+
+    def test_non_numeric_input_types(self):
+        # Test possible non-numeric types for the argument x, including
+        # subclasses of the explicitly documented accepted types.
+        class CustomStr(str): pass
+        class CustomBytes(bytes): pass
+        class CustomByteArray(bytearray): pass
+
+        values = [b'100',
+                  bytearray(b'100'),
+                  CustomStr('100'),
+                  CustomBytes(b'100'),
+                  CustomByteArray(b'100')]
+
+        for x in values:
+            msg = 'x has value %r and type %s' % (x, type(x).__name__)
+            try:
+                self.assertEqual(int(x), 100, msg=msg)
+                self.assertEqual(int(x, 2), 4, msg=msg)
+            except TypeError as err:
+                raise AssertionError('For %s got TypeError: %s' %
+                                     (type(x).__name__, err))
+
+        from collections import UserString
+        values = [UserString('100')]
+        for x in values:
+            msg = 'x has value %r and type %s' % (x, type(x).__name__)
+            try:
+                self.assertEqual(int(x), 100, msg=msg)
+            except TypeError as err:
+                raise AssertionError('For %s got TypeError: %s' %
+                                     (type(x).__name__, err))
+            self.assertRaises(TypeError, int, x, 2)
+
+    def test_string_float(self):
+        self.assertRaises(ValueError, int, '1.2')
+
+    def test_invalid_base(self):
+        for base in -1, 1, 37, 2**1000, -2**1000:
+            self.assertRaises(ValueError, int, '100', base)
+        for base in '10',:
+            self.assertRaises(TypeError, int, '100', base)
+        # XXX ?
+        self.assertEqual(int('100', 10.5), 100)
+
     def test_intconversion(self):
         # Test __int__()
         class ClassicMissingMethods:
diff -r ffe091ebd5de Objects/longobject.c
--- a/Objects/longobject.c	Mon Dec 24 13:15:43 2012 +0200
+++ b/Objects/longobject.c	Mon Dec 24 21:43:43 2012 +0200
@@ -4130,8 +4130,14 @@
     if (!PyArg_ParseTupleAndKeywords(args, kwds, "|OO:int", kwlist,
                                      &x, &obase))
         return NULL;
-    if (x == NULL)
+    if (x == NULL) {
+        if (obase != NULL) {
+            PyErr_SetString(PyExc_TypeError,
+                            "int() missing string argument");
+            return NULL;
+        }
         return PyLong_FromLong(0L);
+    }
     if (obase == NULL)
         return PyNumber_Long(x);
 
@@ -4140,7 +4146,7 @@
         return NULL;
     if (overflow || (base != 0 && base < 2) || base > 36) {
         PyErr_SetString(PyExc_ValueError,
-                        "int() arg 2 must be >= 2 and <= 36");
+                        "int() base must be >= 2 and <= 36");
         return NULL;
     }