diff -r 937f70110f9e Lib/test/test_int.py
--- a/Lib/test/test_int.py	Sun Dec 23 19:55:21 2012 +0200
+++ b/Lib/test/test_int.py	Mon Dec 24 11:46:52 2012 +0200
@@ -221,6 +221,40 @@
         self.assertEqual(int('2br45qc', 35), 4294967297)
         self.assertEqual(int('1z141z5', 36), 4294967297)
 
+    def test_no_args(self):
+        self.assertEquals(int(), 0)
+
+    def test_keyword_args(self):
+        # Test invoking int() using keyword arguments.
+        self.assertEquals(int(x=1.2), 1)
+        self.assertEquals(int('100', base=2), 4)
+        self.assertEquals(int(x='100', base=2), 4)
+
+    def test_base_arg_with_no_x_arg(self):
+        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 type %s' % type(x).__name__
+            self.assertEquals(int(x), 100, msg=msg)
+            self.assertEquals(int(x, 2), 4, msg=msg)
+
+    def test_string_float(self):
+        self.assertRaises(ValueError, int, '1.2')
+
     def test_intconversion(self):
         # Test __int__()
         class ClassicMissingMethods:
diff -r 937f70110f9e Objects/longobject.c
--- a/Objects/longobject.c	Sun Dec 23 19:55:21 2012 +0200
+++ b/Objects/longobject.c	Mon Dec 24 11:46:52 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;
     }