content: /*
   * Copyright 1999-2023 Alibaba Group Holding Ltd.
   *
   * Licensed 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 com.alibaba.nacos.common.utils;
  
  import org.junit.jupiter.api.AfterEach;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  import org.junit.jupiter.api.extension.ExtendWith;
  import org.mockito.Mock;
  import org.mockito.junit.jupiter.MockitoExtension;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  import static org.mockito.Mockito.never;
  import static org.mockito.Mockito.reset;
  import static org.mockito.Mockito.verify;
  
  @ExtendWith(MockitoExtension.class)
  class ObservableTest {
      
      @Mock
      private Observer observer;
      
      private Observable observable;
      
      @BeforeEach
      void setUp() throws Exception {
          observable = new Observable();
      }
      
      @AfterEach
      void tearDown() throws Exception {
      }
      
      @Test
      void testAddObserver() {
          observable.addObserver(observer);
          assertEquals(1, observable.countObservers());
          verify(observer).update(observable);
      }
      
      @Test
      void testDeleteObserver() {
          observable.addObserver(observer);
          assertEquals(1, observable.countObservers());
          observable.deleteObserver(observer);
          assertEquals(0, observable.countObservers());
      }
      
      @Test
      void testNotifyObservers() {
          observable.addObserver(observer);
          reset(observer);
          observable.notifyObservers();
          assertFalse(observable.hasChanged());
          verify(observer, never()).update(observable);
          observable.setChanged();
          assertTrue(observable.hasChanged());
          observable.notifyObservers();
          verify(observer).update(observable);
          assertFalse(observable.hasChanged());
      }
      
      @Test
      void testDeleteObservers() {
          observable.addObserver(observer);
          observable.deleteObservers();
          assertEquals(1, observable.countObservers());
      }
  }