@Test
public void testNamePatternEnvironmentPropertyNotSet() {

  assertThat(System.getenv("my_prop"), nullValue());
  final HeapDumpNameFormatter subject =
      new HeapDumpNameFormatter("hda_%env:my_prop%.hprof", "my_host", uuidProvider);
  assertThat(subject.format(date), is("hda_.hprof"));
}