@Test
  public void testResolveEntityNotFoundSystemId() throws Exception {
    final String systemId = "http://schema.pivotal.io/this/should/be/not/found.xsd";
    final InputSource inputSource = getEntityResolver().resolveEntity(null, systemId);
    assertNull(inputSource);
  }
Test {@link PivotalEntityResolver#resolveEntity(String, String)} with
<code>"http://schema.pivotal.io/this/should/be/not/found.xsd"</code> <code>systemId</code>,
which should not be found. Asserts that returns to <code>null</code>.

@since GemFire 8.1
geode-core/src/test/java/org/apache/geode/internal/cache/xmlcache/AbstractEntityResolverTest.java