public virtual void testOverlapMap()
        {
            JDFAttributeMap m1 = new JDFAttributeMap("a1", "v1");

            m1.put("a2", "v2");
            Assert.IsTrue(m1.overlapMap((JDFAttributeMap)null));
            JDFAttributeMap m2 = new JDFAttributeMap("a1", "v1");

            Assert.IsTrue(m1.overlapMap(m2));
            m2.put("a2", "v2");
            Assert.IsTrue(m1.overlapMap(m2));
            m2.put("a2", "v3");
            Assert.IsFalse(m1.overlapMap(m2));
            m2.put("a2", "v2");
            Assert.IsTrue(m1.overlapMap(m2));
            m2.put("a2", "*");
            Assert.IsTrue(m1.overlapMap(m2));
            m2.put("a3", "v3");
            Assert.IsTrue(m1.overlapMap(m2));
            m2.put("a4", null);
            Assert.IsTrue(m1.overlapMap(m2));
            m2.put("a4", null);
            Assert.IsTrue(m1.overlapMap(m2));
            m1.put("a4", null);
            Assert.IsTrue(m1.overlapMap(m2));
            Assert.IsTrue(m1.overlapMap((JDFAttributeMap)null));
        }