@Test
  public void testGetConfig() throws Exception {
    setupSerializer();
    Properties props = new Properties();
    props.put("classes",
        "Pdx#exclude=string.*#exclude=badField, Pdx#identity=id.*, PdxAuto#exclude=long.*#identity=id.*");
    serializer.initialize(c, props);

    Properties result = serializer.getConfig();
    assertEquals(
        "Pdx, PdxAuto, Pdx#identity=id.*, PdxAuto#identity=id.*, Pdx#exclude=string.*, Pdx#exclude=badField, PdxAuto#exclude=long.*",
        result.getProperty("classes"));

    manager.resetCaches();
    serializer.initialize(c, result);

    result = serializer.getConfig();
    assertEquals(
        "Pdx, PdxAuto, Pdx#identity=id.*, PdxAuto#identity=id.*, Pdx#exclude=string.*, Pdx#exclude=badField, PdxAuto#exclude=long.*",
        result.getProperty("classes"));
  }
A serializable with a writeReplace method should use standard serialization.
geode-core/src/integrationTest/java/org/apache/geode/pdx/AutoSerializableJUnitTest.java