Fixes gh-1209 (#1239)

spring-cloud-commons/src/main/java/org/springframework/cloud/client/discovery/composite/CompositeDiscoveryClient.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2023 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.
@@ -31,6 +31,7 @@ import org.springframework.core.annotation.AnnotationAwareOrderComparator;
  *
  * @author Biju Kunjummen
  * @author Olga Maciaszek-Sharma
+ * @author Sean Ruffatti
  */
 public class CompositeDiscoveryClient implements DiscoveryClient {
 
@@ -73,6 +74,15 @@ public class CompositeDiscoveryClient implements DiscoveryClient {
 		return new ArrayList<>(services);
 	}
 
+	@Override
+	public void probe() {
+		if (this.discoveryClients != null) {
+			for (DiscoveryClient discoveryClient : this.discoveryClients) {
+				discoveryClient.probe();
+			}
+		}
+	}
+
 	public List<DiscoveryClient> getDiscoveryClients() {
 		return this.discoveryClients;
 	}

spring-cloud-commons/src/test/java/org/springframework/cloud/client/discovery/composite/CompositeDiscoveryClientUnitTests.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright 2012-2023 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.cloud.client.discovery.composite;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+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 org.springframework.cloud.client.DefaultServiceInstance;
+import org.springframework.cloud.client.ServiceInstance;
+import org.springframework.cloud.client.discovery.DiscoveryClient;
+
+import static org.assertj.core.api.BDDAssertions.then;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+/**
+ * Mockito tests for Composite Discovery Client
+ *
+ * @author Sean Ruffatti
+ */
+@ExtendWith(MockitoExtension.class)
+public class CompositeDiscoveryClientUnitTests {
+
+	private CompositeDiscoveryClient underTest;
+
+	@Mock
+	private DiscoveryClient client1;
+
+	@Mock
+	private DiscoveryClient client2;
+
+	@BeforeEach
+	void setUp() {
+		underTest = new CompositeDiscoveryClient(Arrays.asList(client1, client2));
+	}
+
+	@Test
+	void shouldRetrieveInstancesByServiceId() {
+		ServiceInstance serviceInstance1 = new DefaultServiceInstance("instance1", "serviceId", "https://s1", 8443,
+				true);
+		when(client1.getInstances("serviceId")).thenReturn(Collections.singletonList(serviceInstance1));
+
+		List<ServiceInstance> serviceInstances = underTest.getInstances("serviceId");
+
+		then(serviceInstances.get(0).getInstanceId()).isEqualTo("instance1");
+		then(serviceInstances.get(0).getServiceId()).isEqualTo("serviceId");
+		then(serviceInstances.get(0).getHost()).isEqualTo("https://s1");
+		then(serviceInstances.get(0).getPort()).isEqualTo(8443);
+	}
+
+	@Test
+	void shouldReturnServiceIds() {
+		when(client1.getServices()).thenReturn(Collections.singletonList("serviceId1"));
+		when(client2.getServices()).thenReturn(Collections.singletonList("serviceId2"));
+
+		List<String> services = underTest.getServices();
+
+		then(services.size()).isEqualTo(2);
+		then(services).containsOnlyOnce("serviceId1", "serviceId2");
+	}
+
+	@Test
+	void shouldReturnAllDiscoveryClients() {
+		then(underTest.getDiscoveryClients()).containsOnlyOnce(client1, client2);
+	}
+
+	@Test
+	void shouldCallProbeOnAllDiscoveryClients() {
+		underTest.probe();
+
+		// Every DiscoveryClient bean should invoke DiscoveryClient.probe() when
+		// CompositeDiscoveryClient.probe() is invoked.
+		verify(client1, times(1)).probe();
+		verify(client1, times(0)).getServices();
+		verify(client2, times(1)).probe();
+		verify(client2, times(0)).getServices();
+	}
+
+}