diff --git a/OpenSSL/test/util.py b/OpenSSL/test/util.py
index 4e4d812..c87ce09 100644
--- a/OpenSSL/test/util.py
+++ b/OpenSSL/test/util.py
@@ -300,3 +300,133 @@
         self.assertTrue(isinstance(theType, type))
         instance = theType(*constructionArgs)
         self.assertIdentical(type(instance), theType)
+
+
+
+class EqualityTestsMixin(object):
+    """
+    A mixin defining tests for the standard implementation of C{==} and C{!=}.
+    """
+    def anInstance(self):
+        """
+        Return an instance of the class under test.  Each call to this method
+        must return a different object.  All objects returned must be equal to
+        each other.
+        """
+        raise NotImplementedError()
+
+
+    def anotherInstance(self):
+        """
+        Return an instance of the class under test.  Each call to this method
+        must return a different object.  The objects must not be equal to the
+        objects returned by C{anInstance}.  They may or may not be equal to
+        each other (they will not be compared against each other).
+        """
+        raise NotImplementedError()
+
+
+    def test_identicalEq(self):
+        """
+        An object compares equal to itself using the C{==} operator.
+        """
+        o = self.anInstance()
+        self.assertTrue(o == o)
+
+
+    def test_identicalNe(self):
+        """
+        An object doesn't compare not equal to itself using the C{!=} operator.
+        """
+        o = self.anInstance()
+        self.assertFalse(o != o)
+
+
+    def test_sameEq(self):
+        """
+        Two objects that are equal to each other compare equal to each other
+        using the C{==} operator.
+        """
+        a = self.anInstance()
+        b = self.anInstance()
+        self.assertTrue(a == b)
+
+
+    def test_sameNe(self):
+        """
+        Two objects that are equal to each other do not compare not equal to
+        each other using the C{!=} operator.
+        """
+        a = self.anInstance()
+        b = self.anInstance()
+        self.assertFalse(a != b)
+
+
+    def test_differentEq(self):
+        """
+        Two objects that are not equal to each other do not compare equal to
+        each other using the C{==} operator.
+        """
+        a = self.anInstance()
+        b = self.anotherInstance()
+        self.assertFalse(a == b)
+
+
+    def test_differentNe(self):
+        """
+        Two objects that are not equal to each other compare not equal to each
+        other using the C{!=} operator.
+        """
+        a = self.anInstance()
+        b = self.anotherInstance()
+        self.assertTrue(a != b)
+
+
+    def test_anotherTypeEq(self):
+        """
+        The object does not compare equal to an object of an unrelated type
+        (which does not implement the comparison) using the C{==} operator.
+        """
+        a = self.anInstance()
+        b = object()
+        self.assertFalse(a == b)
+
+
+    def test_anotherTypeNe(self):
+        """
+        The object compares not equal to an object of an unrelated type (which
+        does not implement the comparison) using the C{!=} operator.
+        """
+        a = self.anInstance()
+        b = object()
+        self.assertTrue(a != b)
+
+
+    def test_delegatedEq(self):
+        """
+        The result of comparison using C{==} is delegated to the right-hand
+        operand if it is of an unrelated type.
+        """
+        class Delegate(object):
+            def __eq__(self, other):
+                # Do something crazy and obvious.
+                return [self]
+
+        a = self.anInstance()
+        b = Delegate()
+        self.assertEqual(a == b, [b])
+
+
+    def test_delegateNe(self):
+        """
+        The result of comparison using C{!=} is delegated to the right-hand
+        operand if it is of an unrelated type.
+        """
+        class Delegate(object):
+            def __ne__(self, other):
+                # Do something crazy and obvious.
+                return [self]
+
+        a = self.anInstance()
+        b = Delegate()
+        self.assertEqual(a != b, [b])