Rudimentary test for the invalid csrf token error view.

src/zope/formlib/errors.py

@@ -64,7 +64,11 @@ def update(self):
             'Pragma', 'no-cache')
 
     def render(self):
-        msg = self.context.doc
+        msg = self.context.args[0]
         if isinstance(msg, Message):
             msg = translate(msg, context=self.request)
         return escape(msg)
+
+    def __call__(self):
+        self.update()
+        return self.render()

src/zope/formlib/form.txt

@@ -2182,3 +2182,13 @@ We can indeed submit data to the forms::
     >>> multi = MultiForm(None, request)
     >>> _ = multi()
     Action: handle in Form Two
+
+There is a view for the InvalidCSRFTokenError::
+
+    >>> from zope.component import getMultiAdapter
+    >>> from zope.formlib.interfaces import InvalidCSRFTokenError
+    >>> from zope.formlib.errors import InvalidCSRFTokenErrorView
+    >>> error = InvalidCSRFTokenError('Invalid CSRF token')
+    >>> request = TestRequest()
+    >>> print(InvalidCSRFTokenErrorView(error, request)())
+    Invalid CSRF token