diff -r ac27d979078a Lib/test/test_csv.py
--- a/Lib/test/test_csv.py	Thu Sep 05 00:23:08 2013 +0200
+++ b/Lib/test/test_csv.py	Thu Sep 05 17:20:42 2013 +0800
@@ -22,7 +22,7 @@
         self.assertRaises(TypeError, ctor, None)
         self.assertRaises(TypeError, ctor, arg, bad_attr = 0)
         self.assertRaises(TypeError, ctor, arg, delimiter = 0)
-        self.assertRaises(TypeError, ctor, arg, delimiter = 'XX')
+        self.assertRaises(ValueError, ctor, arg, delimiter = 'XX')
         self.assertRaises(csv.Error, ctor, arg, 'foo')
         self.assertRaises(TypeError, ctor, arg, delimiter=None)
         self.assertRaises(TypeError, ctor, arg, delimiter=1)
@@ -754,27 +754,11 @@
         d = mydialect()
 
         mydialect.quotechar = "''"
-        self.assertRaises(csv.Error, mydialect)
+        self.assertRaises(ValueError, mydialect)
 
         mydialect.quotechar = 4
         self.assertRaises(csv.Error, mydialect)
 
-    def test_delimiter(self):
-        class mydialect(csv.Dialect):
-            delimiter = ";"
-            escapechar = '\\'
-            doublequote = False
-            skipinitialspace = True
-            lineterminator = '\r\n'
-            quoting = csv.QUOTE_NONE
-        d = mydialect()
-
-        mydialect.delimiter = ":::"
-        self.assertRaises(csv.Error, mydialect)
-
-        mydialect.delimiter = 4
-        self.assertRaises(csv.Error, mydialect)
-
     def test_lineterminator(self):
         class mydialect(csv.Dialect):
             delimiter = ";"
@@ -791,6 +775,22 @@
         mydialect.lineterminator = 4
         self.assertRaises(csv.Error, mydialect)
 
+    def test_invaliddelimiter(self):
+        class mydialect(csv.Dialect):
+            delimiter = b","
+
+        with self.assertRaises(csv.Error) as cm:
+            mydialect()
+        self.assertEqual(str(cm.exception),
+                         '"delimiter" must be string, not bytes')
+
+        mydialect.delimiter = 4
+
+        with self.assertRaises(csv.Error) as cm:
+            mydialect()
+        self.assertEqual(str(cm.exception),
+                         '"delimiter" must be string, not int')
+
 
 class TestSniffer(unittest.TestCase):
     sample1 = """\
diff -r ac27d979078a Modules/_csv.c
--- a/Modules/_csv.c	Thu Sep 05 00:23:08 2013 +0200
+++ b/Modules/_csv.c	Thu Sep 05 17:20:42 2013 +0800
@@ -239,11 +239,16 @@
         *target = '\0';
         if (src != Py_None) {
             Py_ssize_t len;
+            if (!PyUnicode_Check(src)) {
+                PyErr_Format(PyExc_TypeError,
+                    "\"%s\" must be string, not %s", name,
+                    src->ob_type->tp_name);
+                return -1;
+            }
             len = PyUnicode_GetLength(src);
             if (len > 1) {
-                PyErr_Format(PyExc_TypeError,
-                    "\"%s\" must be an 1-character string",
-                    name);
+                PyErr_Format(PyExc_ValueError,
+                    "\"%s\" must be an 1-character string", name);
                 return -1;
             }
             /* PyUnicode_READY() is called in PyUnicode_GetLength() */