diff -r 98f82b124c7d Lib/csv.py
--- a/Lib/csv.py	Sat Sep 07 10:36:04 2013 +0200
+++ b/Lib/csv.py	Sat Sep 07 18:58:57 2013 +0800
@@ -46,7 +46,7 @@
     def _validate(self):
         try:
             _Dialect(self)
-        except TypeError as e:
+        except (TypeError, ValueError) as e:
             # We do this for compatibility with py2.3
             raise Error(str(e))
 
diff -r 98f82b124c7d Lib/test/test_csv.py
--- a/Lib/test/test_csv.py	Sat Sep 07 10:36:04 2013 +0200
+++ b/Lib/test/test_csv.py	Sat Sep 07 18:58:57 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)
@@ -744,6 +744,7 @@
             lineterminator = '\r\n'
             quoting = csv.QUOTE_NONE
         d = mydialect()
+        self.assertEqual(d.quoting, csv.QUOTE_NONE)
 
         mydialect.quoting = None
         self.assertRaises(csv.Error, mydialect)
@@ -752,12 +753,21 @@
         mydialect.quoting = csv.QUOTE_ALL
         mydialect.quotechar = '"'
         d = mydialect()
+        self.assertEqual(d.quoting, csv.QUOTE_ALL)
+        self.assertEqual(d.quotechar, '"')
+        self.assertTrue(d.doublequote)
 
         mydialect.quotechar = "''"
-        self.assertRaises(csv.Error, mydialect)
+        with self.assertRaises(csv.Error) as cm:
+            mydialect()
+        self.assertEqual(str(cm.exception),
+                         '"quotechar" must be an 1-character string')
 
         mydialect.quotechar = 4
-        self.assertRaises(csv.Error, mydialect)
+        with self.assertRaises(csv.Error) as cm:
+            mydialect()
+        self.assertEqual(str(cm.exception),
+                         '"quotechar" must be string, not int')
 
     def test_delimiter(self):
         class mydialect(csv.Dialect):
@@ -768,12 +778,25 @@
             lineterminator = '\r\n'
             quoting = csv.QUOTE_NONE
         d = mydialect()
+        self.assertEqual(d.delimiter, ";")
 
         mydialect.delimiter = ":::"
-        self.assertRaises(csv.Error, mydialect)
+        with self.assertRaises(csv.Error) as cm:
+            mydialect()
+        self.assertEqual(str(cm.exception),
+                         '"delimiter" must be an 1-character string')
+
+        mydialect.delimiter = b","
+        with self.assertRaises(csv.Error) as cm:
+            mydialect()
+        self.assertEqual(str(cm.exception),
+                         '"delimiter" must be string, not bytes')
 
         mydialect.delimiter = 4
-        self.assertRaises(csv.Error, mydialect)
+        with self.assertRaises(csv.Error) as cm:
+            mydialect()
+        self.assertEqual(str(cm.exception),
+                         '"delimiter" must be string, not int')
 
     def test_lineterminator(self):
         class mydialect(csv.Dialect):
@@ -784,12 +807,17 @@
             lineterminator = '\r\n'
             quoting = csv.QUOTE_NONE
         d = mydialect()
+        self.assertEqual(d.lineterminator, '\r\n')
 
         mydialect.lineterminator = ":::"
         d = mydialect()
+        self.assertEqual(d.lineterminator, ":::")
 
         mydialect.lineterminator = 4
-        self.assertRaises(csv.Error, mydialect)
+        with self.assertRaises(csv.Error) as cm:
+            mydialect()
+        self.assertEqual(str(cm.exception),
+                         '"lineterminator" must be a string')
 
 
 class TestSniffer(unittest.TestCase):
diff -r 98f82b124c7d Modules/_csv.c
--- a/Modules/_csv.c	Sat Sep 07 10:36:04 2013 +0200
+++ b/Modules/_csv.c	Sat Sep 07 18:58:57 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 %.200s", 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() */