fix interpreting is/is not/in/not in

--HG--
branch : trunk

py/code/_assertionnew.py

@@ -68,6 +68,10 @@ operator_map = {
     ast.LtE : "<=",
     ast.Gt : ">",
     ast.GtE : ">=",
+    ast.Is : "is",
+    ast.IsNot : "is not",
+    ast.In : "in",
+    ast.NotIn : "not in"
 }
 
 unary_map = {

py/code/testing/test_assertion.py

@@ -65,6 +65,22 @@ def test_assert_multiline_2():
         s = str(e)
         assert s.startswith('assert 2 ==')
 
+def test_in():
+    try:
+        assert "hi" in [1, 2]
+    except AssertionError:
+        e = exvalue()
+        s = str(e)
+        assert s.startswith("assert 'hi' in")
+
+def test_is():
+    try:
+        assert 1 is 2
+    except AssertionError:
+        e = exvalue()
+        s = str(e)
+        assert s.startswith("assert 1 is 2")
+
 def test_assert_non_string_message(): 
     class A: 
         def __str__(self):