content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License. You may obtain a copy of the License at
   *
   *    http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.kafka.common.telemetry;
  
  import org.junit.jupiter.api.Test;
  import org.junit.jupiter.api.function.Executable;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  
  import static org.junit.jupiter.api.Assertions.assertThrows;
  
  public class ClientTelemetryStateTest {
  
      @Test
      public void testValidateTransitionForSubscriptionNeeded() {
          List<ClientTelemetryState> validStates = new ArrayList<>();
          validStates.add(ClientTelemetryState.SUBSCRIPTION_IN_PROGRESS);
          validStates.add(ClientTelemetryState.TERMINATED);
  
          testValidateTransition(ClientTelemetryState.SUBSCRIPTION_NEEDED, validStates);
      }
  
      @Test
      public void testValidateTransitionForSubscriptionInProgress() {
          List<ClientTelemetryState> validStates = new ArrayList<>();
          validStates.add(ClientTelemetryState.PUSH_NEEDED);
          validStates.add(ClientTelemetryState.SUBSCRIPTION_NEEDED);
          validStates.add(ClientTelemetryState.TERMINATING_PUSH_NEEDED);
          validStates.add(ClientTelemetryState.TERMINATED);
  
          testValidateTransition(ClientTelemetryState.SUBSCRIPTION_IN_PROGRESS, validStates);
      }
  
      @Test
      public void testValidateTransitionForPushNeeded() {
          List<ClientTelemetryState> validStates = new ArrayList<>();
          validStates.add(ClientTelemetryState.PUSH_IN_PROGRESS);
          validStates.add(ClientTelemetryState.SUBSCRIPTION_NEEDED);
          validStates.add(ClientTelemetryState.TERMINATING_PUSH_NEEDED);
          validStates.add(ClientTelemetryState.TERMINATED);
  
          testValidateTransition(ClientTelemetryState.PUSH_NEEDED, validStates);
      }
  
      @Test
      public void testValidateTransitionForPushInProgress() {
          List<ClientTelemetryState> validStates = new ArrayList<>();
          validStates.add(ClientTelemetryState.PUSH_NEEDED);
          validStates.add(ClientTelemetryState.SUBSCRIPTION_NEEDED);
          validStates.add(ClientTelemetryState.TERMINATING_PUSH_NEEDED);
          validStates.add(ClientTelemetryState.TERMINATED);
  
          testValidateTransition(ClientTelemetryState.PUSH_IN_PROGRESS, validStates);
      }
  
      @Test
      public void testValidateTransitionForTerminating() {
          List<ClientTelemetryState> validStates = new ArrayList<>();
          validStates.add(ClientTelemetryState.TERMINATING_PUSH_IN_PROGRESS);
          validStates.add(ClientTelemetryState.TERMINATED);
  
          testValidateTransition(ClientTelemetryState.TERMINATING_PUSH_NEEDED, validStates);
      }
  
      @Test
      public void testValidateTransitionForTerminatingPushInProgress() {
          testValidateTransition(ClientTelemetryState.TERMINATING_PUSH_IN_PROGRESS,
              Collections.singletonList(ClientTelemetryState.TERMINATED));
      }
  
      @Test
      public void testValidateTransitionForTerminated() {
          // There's no transitioning out of the terminated state
          testValidateTransition(ClientTelemetryState.TERMINATED, Collections.emptyList());
      }
  
      private void testValidateTransition(ClientTelemetryState oldState, List<ClientTelemetryState> validStates) {
          for (ClientTelemetryState newState : validStates) {
              oldState.validateTransition(newState);
          }
  
          // Copy value to a new list for modification.
          List<ClientTelemetryState> invalidStates = new ArrayList<>(Arrays.asList(ClientTelemetryState.values()));
          // Remove the valid states from the list of all states, leaving only the invalid.
          invalidStates.removeAll(validStates);
  
          for (ClientTelemetryState newState : invalidStates) {
              Executable e = () -> oldState.validateTransition(newState);
              String unexpectedSuccessMessage = "Should have thrown an IllegalTelemetryStateException for transitioning from " + oldState + " to " + newState;
              assertThrows(IllegalStateException.class, e, unexpectedSuccessMessage);
          }
      }
  
  }
  