diff --git a/testing/install_external_dependencies.sh b/testing/install_external_dependencies.sh
index d6c07368b9d..a120d6174dc 100755
--- a/testing/install_external_dependencies.sh
+++ b/testing/install_external_dependencies.sh
@@ -44,6 +44,6 @@ if [[ -n "$PYTHON" ]] ; then
   conda update -q conda
   conda info -a
   conda config --add channels conda-forge
-  conda install -q matplotlib pandasql ipython=5.4.1 jupyter_client ipykernel matplotlib bokeh=0.12.10
+  conda install -q matplotlib=2.1.2 pandasql ipython=5.4.1 jupyter_client ipykernel matplotlib bokeh=0.12.10
   pip install -q grpcio ggplot bkzep==0.4.0
 fi
diff --git a/zeppelin-zengine/src/test/java/org/apache/zeppelin/interpreter/mock/MockInterpreter1.java b/zeppelin-zengine/src/test/java/org/apache/zeppelin/interpreter/mock/MockInterpreter1.java
index a533c12913e..500c4f72094 100644
--- a/zeppelin-zengine/src/test/java/org/apache/zeppelin/interpreter/mock/MockInterpreter1.java
+++ b/zeppelin-zengine/src/test/java/org/apache/zeppelin/interpreter/mock/MockInterpreter1.java
@@ -24,18 +24,27 @@
 import org.apache.zeppelin.scheduler.Scheduler;
 import org.apache.zeppelin.scheduler.SchedulerFactory;
 
+import java.lang.management.ManagementFactory;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
+import java.util.concurrent.atomic.AtomicInteger;
 
 public class MockInterpreter1 extends Interpreter {
 
+	private static AtomicInteger IdGenerator = new AtomicInteger();
+
+	private int object_id;
+	private String pid;
 	Map<String, Object> vars = new HashMap<>();
 
 	public MockInterpreter1(Properties property) {
 		super(property);
+		this.object_id = IdGenerator.getAndIncrement();
+		this.pid = ManagementFactory.getRuntimeMXBean().getName().split("@")[0];
 	}
+
 	boolean open;
 
 
@@ -60,7 +69,7 @@ public InterpreterResult interpret(String st, InterpreterContext context) {
 
 		if ("getId".equals(st)) {
 			// get unique id of this interpreter instance
-			result = new InterpreterResult(InterpreterResult.Code.SUCCESS, "" + this.hashCode());
+			result = new InterpreterResult(InterpreterResult.Code.SUCCESS, "" + this.object_id + "-" + this.pid);
 		} else if (st.startsWith("sleep")) {
 			try {
 				Thread.sleep(Integer.parseInt(st.split(" ")[1]));
diff --git a/zeppelin-zengine/src/test/java/org/apache/zeppelin/notebook/NotebookTest.java b/zeppelin-zengine/src/test/java/org/apache/zeppelin/notebook/NotebookTest.java
index 122395cc611..ee04291be5b 100644
--- a/zeppelin-zengine/src/test/java/org/apache/zeppelin/notebook/NotebookTest.java
+++ b/zeppelin-zengine/src/test/java/org/apache/zeppelin/notebook/NotebookTest.java
@@ -44,6 +44,10 @@
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
+import org.junit.runner.JUnitCore;
+import org.junit.runner.Request;
+import org.junit.runner.Result;
+import org.mockito.internal.runners.JUnit44RunnerImpl;
 import org.quartz.SchedulerException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -1450,4 +1454,5 @@ public void afterStatusChange(Job job, Status before, Status after) {
   private interface StatusChangedListener {
     void onStatusChanged(Job job, Status before, Status after);
   }
+
 }