Introduce the QuorumLostEvent class extending MembershipEvent to signal that a quorum of peer members was lost in the event of a split brain or network partition.

apache-geode-extensions/src/test/java/org/springframework/geode/distributed/event/support/QuorumLostEventUnitTests.java

@@ -0,0 +1,140 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * 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
+ *
+ *     https://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.springframework.geode.distributed.event.support;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verifyNoInteractions;
+
+import java.util.Collections;
+
+import org.junit.Test;
+
+import org.apache.geode.distributed.DistributedMember;
+import org.apache.geode.distributed.internal.DistributionManager;
+
+import org.springframework.geode.distributed.event.MembershipEvent;
+
+/**
+ * Unit Tests for {@link QuorumLostEvent}.
+ *
+ * @author John Blum
+ * @see org.junit.Test
+ * @see org.mockito.Mockito
+ * @see org.apache.geode.distributed.DistributedMember
+ * @see org.springframework.geode.distributed.event.MembershipEvent
+ * @see org.springframework.geode.distributed.event.support.QuorumLostEvent
+ * @since 1.3.0
+ */
+public class QuorumLostEventUnitTests {
+
+	@SuppressWarnings("unchecked")
+	private <T> Iterable<T> normalize(Iterable<? extends T> iterable) {
+		return (Iterable<T>) iterable;
+	}
+
+	@Test
+	public void constructsQuorumLostEvent() {
+
+		DistributionManager mockDistributionManager = mock(DistributionManager.class);
+
+		QuorumLostEvent event = new QuorumLostEvent(mockDistributionManager);
+
+		assertThat(event).isNotNull();
+		assertThat(event.getDistributionManager()).isEqualTo(mockDistributionManager);
+		assertThat(event.getFailedMembers()).isEmpty();
+		assertThat(event.getRemainingMembers()).isEmpty();
+		assertThat(event.getType()).isEqualTo(MembershipEvent.Type.QUORUM_LOST);
+
+		verifyNoInteractions(mockDistributionManager);
+	}
+
+	@Test
+	public void setAndGetFailedMembers() {
+
+		DistributedMember mockMemberOne = mock(DistributedMember.class);
+		DistributedMember mockMemberTwo = mock(DistributedMember.class);
+
+		DistributionManager mockDistributionManager = mock(DistributionManager.class);
+
+		QuorumLostEvent event = new QuorumLostEvent(mockDistributionManager);
+
+		assertThat(event).isNotNull();
+		assertThat(event.getFailedMembers()).isNotNull();
+		assertThat(event.getFailedMembers()).isEmpty();
+
+		assertThat(event.withFailedMembers(mockMemberOne, mockMemberTwo)).isSameAs(event);
+		assertThat(this.<DistributedMember>normalize(event.getFailedMembers()))
+			.containsExactlyInAnyOrder(mockMemberOne, mockMemberTwo);
+
+		assertThat(event.withFailedMembers((DistributedMember[]) null)).isSameAs(event);
+		assertThat(event.getFailedMembers()).isNotNull();
+		assertThat(event.getFailedMembers()).isEmpty();
+
+		assertThat(event.withFailedMembers(mockMemberOne)).isSameAs(event);
+		assertThat(this.<DistributedMember>normalize(event.getFailedMembers())).containsExactly(mockMemberOne);
+
+		assertThat(event.withFailedMembers((Iterable<? extends DistributedMember>) null)).isSameAs(event);
+		assertThat(event.getFailedMembers()).isNotNull();
+		assertThat(event.getFailedMembers()).isEmpty();
+
+		assertThat(event.withFailedMembers(Collections.singleton(mockMemberTwo))).isSameAs(event);
+		assertThat(this.<DistributedMember>normalize(event.getFailedMembers())).containsExactly(mockMemberTwo);
+
+		assertThat(event.withFailedMembers()).isSameAs(event);
+		assertThat(event.getFailedMembers()).isNotNull();
+		assertThat(event.getFailedMembers()).isEmpty();
+	}
+
+	@Test
+	public void setAndGetRemainingMembers() {
+
+		DistributedMember mockMemberOne = mock(DistributedMember.class);
+		DistributedMember mockMemberTwo = mock(DistributedMember.class);
+
+		DistributionManager mockDistributionManager = mock(DistributionManager.class);
+
+		QuorumLostEvent event = new QuorumLostEvent(mockDistributionManager);
+
+		assertThat(event).isNotNull();
+		assertThat(event.getRemainingMembers()).isNotNull();
+		assertThat(event.getRemainingMembers()).isEmpty();
+
+		assertThat(event.withRemainingMembers(mockMemberOne, mockMemberTwo)).isSameAs(event);
+		assertThat(this.<DistributedMember>normalize(event.getRemainingMembers()))
+			.containsExactlyInAnyOrder(mockMemberOne, mockMemberTwo);
+
+		assertThat(event.withRemainingMembers((DistributedMember[]) null)).isSameAs(event);
+		assertThat(event.getRemainingMembers()).isNotNull();
+		assertThat(event.getRemainingMembers()).isEmpty();
+
+		assertThat(event.withRemainingMembers(mockMemberOne)).isSameAs(event);
+		assertThat(this.<DistributedMember>normalize(event.getRemainingMembers()))
+			.containsExactlyInAnyOrder(mockMemberOne);
+
+		assertThat(event.withRemainingMembers((Iterable<? extends DistributedMember>) null)).isSameAs(event);
+		assertThat(event.getRemainingMembers()).isNotNull();
+		assertThat(event.getRemainingMembers()).isEmpty();
+
+		assertThat(event.withRemainingMembers(Collections.singletonList(mockMemberTwo))).isSameAs(event);
+		assertThat(this.<DistributedMember>normalize(event.getRemainingMembers()))
+			.containsExactlyInAnyOrder(mockMemberTwo);
+
+		assertThat(event.withRemainingMembers()).isSameAs(event);
+		assertThat(event.getRemainingMembers()).isNotNull();
+		assertThat(event.getRemainingMembers()).isEmpty();
+	}
+}