@Test
  public void testStateMachineProcedure() {
    SimpleStateMachineProcedure p = new SimpleStateMachineProcedure();
    ProcedureState state = ProcedureState.RUNNABLE;
    p.setState(state);
    p.setNextState(ServerCrashState.SERVER_CRASH_ASSIGN);
    // Just assert that the toString basically works and has state in it.
    assertTrue(p.toString().contains(state.toString()));
    assertTrue(p.toString().contains(ServerCrashState.SERVER_CRASH_ASSIGN.toString()));
  }
Do-nothing SimpleMachineProcedure for checking its toString.
hbase-procedure/src/test/java/org/apache/hadoop/hbase/procedure2/TestProcedureToString.java