Remove log4j dependency and update the relevant UT

pom.xml

@@ -139,17 +139,21 @@
                 </exclusion>
             </exclusions>
         </dependency>
-        <dependency>
-            <groupId>org.slf4j</groupId>
-            <artifactId>slf4j-log4j12</artifactId>
-            <version>${slf4j.version}</version>
-            <scope>test</scope>
-        </dependency>
         <!-- Gremlin -->
         <dependency>
             <groupId>org.apache.tinkerpop</groupId>
             <artifactId>gremlin-core</artifactId>
             <version>${tinkerpop.version}</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.slf4j</groupId>
+                    <artifactId>slf4j-log4j12</artifactId>
+                </exclusion>
+                <exclusion>
+                    <groupId>log4j</groupId>
+                    <artifactId>log4j</artifactId>
+                </exclusion>
+            </exclusions>
         </dependency>
         <dependency>
             <groupId>junit</groupId>
@@ -173,13 +177,6 @@
             <artifactId>aws-java-sdk-core</artifactId>
             <version>${aws.java.sdk.version}</version>
         </dependency>
-        <!--TODO remove log4j if possible-->
-        <dependency>
-            <groupId>log4j</groupId>
-            <artifactId>log4j</artifactId>
-            <version>1.2.17</version>
-            <scope>test</scope>
-        </dependency>
         <dependency>
             <groupId>commons-configuration</groupId>
             <artifactId>commons-configuration</artifactId>
@@ -201,6 +198,12 @@
             <artifactId>guava</artifactId>
             <version>${guava.version}</version>
         </dependency>
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-classic</artifactId>
+            <version>1.2.3</version>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-all</artifactId>

src/test/java/com/amazon/janusgraph/TestCiHeartbeat.java

@@ -15,79 +15,58 @@
 
 package com.amazon.janusgraph;
 
-import static org.mockito.Mockito.times;
-import static org.mockito.Mockito.verify;
-
-import org.apache.log4j.Appender;
-import org.apache.log4j.Level;
-import org.apache.log4j.Logger;
-import org.apache.log4j.spi.LoggingEvent;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.read.ListAppender;
+import com.amazon.janusgraph.testutils.HeartbeatTimerTask;
+import com.amazon.janusgraph.testutils.LoggerTestUtil;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TestName;
 import org.junit.runner.RunWith;
-import org.mockito.ArgumentCaptor;
-import org.mockito.Captor;
-import org.mockito.Mock;
 import org.mockito.runners.MockitoJUnitRunner;
 
 import com.amazon.janusgraph.testutils.CiHeartbeat;
 
 /**
- *
- * @author Johan Jacobs
+ * Refer to https://www.baeldung.com/logback
+ * @author Minghui Tang
  *
  */
 @RunWith(MockitoJUnitRunner.class)
 public class TestCiHeartbeat {
-
     @Rule
     public final TestName testName = new TestName();
 
-    @Mock
-    private Appender mockAppender;
-    @Captor
-    private ArgumentCaptor<LoggingEvent> captorLoggingEvent;
+    private ListAppender<ILoggingEvent> ciHeartbeatListAppender;
+    private ListAppender<ILoggingEvent> heartbeatTimerListAppender;
+    private CiHeartbeat ciHeartbeat;
 
     @Before
     public void setup() {
+        ciHeartbeatListAppender = LoggerTestUtil.getListAppenderForClass(CiHeartbeat.class);
+        heartbeatTimerListAppender = LoggerTestUtil.getListAppenderForClass(HeartbeatTimerTask.class);
 
-        final Logger root = Logger.getRootLogger();
-        root.addAppender(mockAppender);
-        root.setLevel(Level.WARN);
+        ciHeartbeat = new CiHeartbeat(500, 3);
     }
 
     @Test
-    public void testHeartbeatConsoleOutput() throws InterruptedException {
-
-        final CiHeartbeat ciHeartbeat = new CiHeartbeat(500, 3);
+    public void testHeartbeatConsoleOutput() throws InterruptedException{
+        // given
 
+        // when
         ciHeartbeat.startHeartbeat(testName.getMethodName());
 
         Thread.sleep(2000);
 
         ciHeartbeat.stopHeartbeat();
 
-        verify(mockAppender, times(6)).doAppend(captorLoggingEvent.capture());
-
-        final LoggingEvent unitTestStartEvent = captorLoggingEvent.getAllValues().get(0);
-        Assert.assertEquals("Heartbeat - [started] - testHeartbeatConsoleOutput - 0ms", unitTestStartEvent.getMessage());
-
-        final LoggingEvent heartbeatOneEvent = captorLoggingEvent.getAllValues().get(1);
-        Assert.assertTrue(heartbeatOneEvent.getMessage().toString().contains("Heartbeat - [1] - testHeartbeatConsoleOutput - "));
-
-        final LoggingEvent heartbeatTwoEvent = captorLoggingEvent.getAllValues().get(2);
-        Assert.assertTrue(heartbeatTwoEvent.getMessage().toString().contains("Heartbeat - [2] - testHeartbeatConsoleOutput - "));
-
-        final LoggingEvent heartbeatThreeEvent = captorLoggingEvent.getAllValues().get(3);
-        Assert.assertTrue(heartbeatThreeEvent.getMessage().toString().contains("Heartbeat - [3] - testHeartbeatConsoleOutput - "));
-
-        final LoggingEvent heartbeatfourEvent = captorLoggingEvent.getAllValues().get(4);
-        Assert.assertTrue(heartbeatfourEvent.getMessage().toString().contains("Heartbeat - [4] - testHeartbeatConsoleOutput - "));
-
-        final LoggingEvent unitTestEndEvent = captorLoggingEvent.getAllValues().get(5);
-        Assert.assertTrue(unitTestEndEvent.getMessage().toString().contains("Heartbeat - [finished] - testHeartbeatConsoleOutput - "));
+        // then
+        Assert.assertEquals(ciHeartbeatListAppender.list.get(0).getFormattedMessage(), "Heartbeat - [started] - testHeartbeatConsoleOutput - 0ms");
+        Assert.assertTrue(heartbeatTimerListAppender.list.get(0).getMessage().contains("Heartbeat - [1] - testHeartbeatConsoleOutput - "));
+        Assert.assertTrue(heartbeatTimerListAppender.list.get(1).getMessage().contains("Heartbeat - [2] - testHeartbeatConsoleOutput - "));
+        Assert.assertTrue(heartbeatTimerListAppender.list.get(2).getMessage().contains("Heartbeat - [3] - testHeartbeatConsoleOutput - "));
+        Assert.assertTrue(ciHeartbeatListAppender.list.get(1).getMessage().contains( "Heartbeat - [finished] - testHeartbeatConsoleOutput - "));
     }
 }

src/test/java/com/amazon/janusgraph/testutils/LoggerTestUtil.java

@@ -0,0 +1,19 @@
+package com.amazon.janusgraph.testutils;
+
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.read.ListAppender;
+import org.slf4j.LoggerFactory;
+
+public class LoggerTestUtil {
+    public static ListAppender<ILoggingEvent> getListAppenderForClass(Class clazz) {
+        Logger logger = (Logger) LoggerFactory.getLogger(clazz);
+
+        ListAppender<ILoggingEvent> loggingEventListAppender = new ListAppender<>();
+        loggingEventListAppender.start();
+
+        logger.addAppender(loggingEventListAppender);
+
+        return loggingEventListAppender;
+    }
+}

src/test/resources/logback.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>
+                %d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="info">
+        <appender-ref ref="CONSOLE"/>
+    </root>
+</configuration>