Add Junit test for ribbon's NIWSServerListClassName #1390 (#1407)

* Add Junit test for ribbon's NIWSServerListClassName

* Add License Head to Code file

* try to solve submodule skywalking-ui conflict

apm-webapp/pom.xml

@@ -88,6 +88,12 @@
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <version>${spring.boot.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>

apm-webapp/src/test/java/org/apache/skywalking/apm/webapp/proxy/NIWSServerListTest.java

@@ -0,0 +1,95 @@
+/*
+ * 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.skywalking.apm.webapp.proxy;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.core.env.AbstractEnvironment;
+import org.springframework.core.env.Environment;
+import org.springframework.core.env.MapPropertySource;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import com.netflix.loadbalancer.Server;
+import com.netflix.loadbalancer.ServerList;
+import com.netflix.loadbalancer.ZoneAwareLoadBalancer;
+import org.springframework.cloud.netflix.ribbon.SpringClientFactory;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@SpringBootTest
+@DirtiesContext
+public class NIWSServerListTest {
+    @Autowired
+    private Environment env;
+
+    @Autowired
+    private SpringClientFactory factory;
+
+    private Map<String, String> serverListClassNames = new HashMap<String, String>();
+
+    @Before
+    public void initServerListClassNames() {
+        for (Iterator<?> iter = ((AbstractEnvironment) env).getPropertySources().iterator(); iter.hasNext();) {
+            Object propertySource = iter.next();
+            if (propertySource instanceof MapPropertySource) {
+                Map<String, Object> mapPropertySource = ((MapPropertySource) propertySource).getSource();
+                for (Map.Entry<String, Object> entry : mapPropertySource.entrySet()) {
+                    String key = entry.getKey();
+                    int index;
+                    if (key.endsWith(".NIWSServerListClassName") &&
+                            (index = key.indexOf(".ribbon")) > 0) {
+                        String clientName = key.substring(0, index);
+                        serverListClassNames.put(clientName,(String)entry.getValue());
+                    }
+                }
+            }
+        }
+    }
+
+    @Test
+    public void serverListClass() throws ClassNotFoundException {
+        for (String serverListClassName : serverListClassNames.values()) {
+            Class<?> clazz = Class.forName(serverListClassName);
+        }
+    }
+
+    @Test
+    public void serverListFliter() {
+        for (Map.Entry<String, String> entry : serverListClassNames.entrySet()) {
+            String clientName = entry.getKey();
+            String serverListClassName = entry.getValue();
+            ServerList<Server> serverList = getLoadBalancer(clientName).getServerListImpl();
+            assertNotNull("Client: " + clientName + "'s ServerListImpl is null",serverList);
+            assertEquals("Clinet: " + clientName + "'s ServerListImpl not Same with setting in configs",
+                    serverListClassName, serverList.getClass().getName());
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    private ZoneAwareLoadBalancer<Server> getLoadBalancer(String name) {
+        return (ZoneAwareLoadBalancer<Server>)this.factory.getLoadBalancer(name);
+    }
+}