### Question:
RollingHelper { public static Step rollServers(Map<String, StepAndPacket> rolling, Step next) { return new RollingStep(rolling, next); } private  RollingHelper(); static Step rollServers(Map<String, StepAndPacket> rolling, Step next);  }### Answer:
@Test public void verifyThatManagedServerPodsAreReplacedInOrder() { initializeExistingPods(); testSupport.addToPacket(SERVERS_TO_ROLL, rolling); SERVER_NAMES.forEach(s -> rolling.put(s, createRollingStepAndPacket(s))); testSupport.runSteps(RollingHelper.rollServers(rolling, terminalStep)); assertThat(logRecords, containsInOrder( containsInfo(MANAGED_POD_REPLACED, SERVER1_NAME), containsInfo(MANAGED_POD_REPLACED, SERVER2_NAME), containsInfo(MANAGED_POD_REPLACED, SERVER10_NAME) )); }
@Test public void verifyThatWhenRollingIsEmpty_NoManagedServerPodsAreReplaced() { initializeExistingPods(); testSupport.addToPacket(SERVERS_TO_ROLL, rolling); testSupport.runSteps(RollingHelper.rollServers(rolling, terminalStep)); assertThat(logRecords, empty()); }