@Test
public void testCurrentMinimumCompatibleLayoutVersion() {

  int expectedMinCompatLV = NameNodeLayoutVersion.Feature.TRUNCATE.getInfo()
      .getLayoutVersion();
  int actualMinCompatLV = LayoutVersion.getMinimumCompatibleLayoutVersion(
      NameNodeLayoutVersion.Feature.values());
  assertEquals("The minimum compatible layout version has changed.  " +
      "Downgrade to prior versions is no longer possible.  Please either " +
      "restore compatibility, or if the incompatibility is intentional, " +
      "then update this assertion.", expectedMinCompatLV, actualMinCompatLV);
}