Make Binary(None) work as expected, adapting to NULL

Issue reported by Stefano Dal Pra.

psycopg/adapter_binary.c

@@ -113,6 +113,12 @@ exit:
     if (got_view) { PyBuffer_Release(&view); }
 #endif
 
+    /* Allow Binary(None) to work */
+    if (self->wrapped == Py_None) {
+        Py_INCREF(psyco_null);
+        rv = psyco_null;
+    }
+
     /* if the wrapped object is not bytes or a buffer, this is an error */
     if (!rv && !PyErr_Occurred()) {
         PyErr_Format(PyExc_TypeError, "can't escape %s to binary",

tests/types_basic.py

@@ -128,6 +128,11 @@ class TypesBasicTests(unittest.TestCase):
             buf = self.execute("SELECT %s::bytea AS foo", (b,))
             self.assertEqual(s, buf)
 
+    def testBinaryNone(self):
+        b = psycopg2.Binary(None)
+        buf = self.execute("SELECT %s::bytea AS foo", (b,))
+        self.assertEqual(buf, None)
+
     def testBinaryEmptyString(self):
         # test to make sure an empty Binary is converted to an empty string
         if sys.version_info[0] < 3: