add test coverage

.travis.yml

@@ -5,3 +5,6 @@ jdk:
   - oraclejdk8
 
 sudo: false
+
+after_success:
+  - mvn clean cobertura:cobertura coveralls:report

pom.xml

@@ -573,6 +573,17 @@
     </dependencyManagement>
 
     <build>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>cobertura-maven-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <groupId>org.eluder.coveralls</groupId>
+                <artifactId>coveralls-maven-plugin</artifactId>
+                <version>3.0.1</version>
+            </plugin>
+        </plugins>
         <pluginManagement>
             <plugins>
                 <plugin>
@@ -655,6 +666,24 @@
                     <artifactId>exec-maven-plugin</artifactId>
                     <version>1.2.1</version>
                 </plugin>
+                <plugin>
+                    <groupId>org.codehaus.mojo</groupId>
+                    <artifactId>cobertura-maven-plugin</artifactId>
+                    <version>2.7</version>
+                    <configuration>
+                        <instrumentation>
+                            <ignores>
+                                <ignore>io.druid.sql.antlr4.*</ignore>
+                            </ignores>
+                            <excludes>
+                                <exclude>io/druid/sql/antlr4/**/*.class</exclude>
+                            </excludes>
+                        </instrumentation>
+                        <format>xml</format>
+                        <!-- aggregated reports for multi-module projects -->
+                        <aggregate>true</aggregate>
+                    </configuration>
+                </plugin>
             </plugins>
         </pluginManagement>
     </build>

server/src/test/resources/log4j2.xml

@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!--
+  ~ Licensed to Metamarkets Group Inc. (Metamarkets) under one
+  ~ or more contributor license agreements.  See the NOTICE file
+  ~ distributed with this work for additional information
+  ~ regarding copyright ownership.  Metamarkets 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.
+  -->
+
+<Configuration status="WARN">
+    <Appenders>
+        <Console name="Console" target="SYSTEM_OUT">
+            <PatternLayout pattern="%d{ISO8601} %p [%t] %c - %m%n"/>
+        </Console>
+    </Appenders>
+    <Loggers>
+        <!-- Override log level for testing to reduce output size -->
+        <Logger name="io.druid.server.coordination.ZkCoordinator" level="warn"/>
+        <Logger name="io.druid.server.coordination.SingleDataSegmentAnnouncer" level="warn"/>
+        <Logger name="io.druid.server.coordination.BatchDataSegmentAnnouncer" level="warn"/>
+        <Root level="info">
+            <AppenderRef ref="Console"/>
+        </Root>
+    </Loggers>
+</Configuration>