/*
 * 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.geode.internal.alerting;

import static org.apache.geode.internal.alerting.AlertingProviderRegistry.getNullAlertingProvider;
import static org.assertj.core.api.Assertions.assertThat;
import static org.mockito.Mockito.mock;

import org.junit.Before;
import org.junit.Test;
import org.junit.experimental.categories.Category;

import org.apache.geode.test.junit.categories.AlertingTest;

/**
 * Unit tests for {@link AlertingProviderRegistry}.
 */
@Category(AlertingTest.class)
public class AlertingProviderRegistryTest {

  private AlertingProvider provider;

  private AlertingProviderRegistry alertingProviderRegistry;

  @Before
  public void setUp() {
    provider = mock(AlertingProvider.class);

    alertingProviderRegistry = new AlertingProviderRegistry();
  }

  @Test
  public void getAlertingProviderIsNullProviderBeforeRegister() {
    assertThat(alertingProviderRegistry.getAlertingProvider()).isSameAs(getNullAlertingProvider());
  }

  @Test
  public void getAlertingProviderIsSameAsRegisteredProvider() {
    alertingProviderRegistry.registerAlertingProvider(provider);

    assertThat(alertingProviderRegistry.getAlertingProvider()).isSameAs(provider);
  }

  @Test
  public void unregisterDoesNothingIfNotRegistered() {
    alertingProviderRegistry.unregisterAlertingProvider(provider);

    assertThat(alertingProviderRegistry.getAlertingProvider()).isSameAs(getNullAlertingProvider());
  }

  @Test
  public void unregisterWrongProviderDoesNothing() {
    alertingProviderRegistry.registerAlertingProvider(provider);

    alertingProviderRegistry.unregisterAlertingProvider(mock(AlertingProvider.class));

    assertThat(alertingProviderRegistry.getAlertingProvider()).isSameAs(provider);
  }

  @Test
  public void unregisterDoesNothingIfNullProvider() {
    alertingProviderRegistry.unregisterAlertingProvider(getNullAlertingProvider());

    assertThat(alertingProviderRegistry.getAlertingProvider()).isSameAs(getNullAlertingProvider());
  }

  @Test
  public void unregisterRemovesRegisteredProvider() {
    alertingProviderRegistry.registerAlertingProvider(provider);

    alertingProviderRegistry.unregisterAlertingProvider(provider);

    assertThat(alertingProviderRegistry.getAlertingProvider()).isSameAs(getNullAlertingProvider());
  }

  @Test
  public void registerAddsAlertingProvider() {
    alertingProviderRegistry.registerAlertingProvider(provider);

    assertThat(alertingProviderRegistry.getAlertingProvider()).isSameAs(provider);
  }
}