chore: added retry for flaky test (#391)

* chore: added retry for flaky test

* lint

* added missing dependency

Author: munkhuushmgl

dialogflow/snippets/pom.xml

@@ -44,6 +44,15 @@
     </dependency>
     <!-- [END dialogflow_install_with_bom] -->
 
+    <dependency>
+      <groupId>com.google.cloud</groupId>
+      <artifactId>google-cloud-core</artifactId>
+      <version>1.94.0</version>
+      <scope>test</scope>
+      <classifier>tests</classifier>
+    </dependency>
+
+
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>

dialogflow/snippets/src/test/java/com/example/dialogflow/CreateDocumentTest.java

@@ -23,13 +23,15 @@
 import com.google.cloud.dialogflow.v2beta1.KnowledgeBase;
 import com.google.cloud.dialogflow.v2beta1.KnowledgeBasesClient;
 import com.google.cloud.dialogflow.v2beta1.ProjectName;
+import com.google.cloud.testing.junit4.MultipleAttemptsRule;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.PrintStream;
 import java.util.UUID;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.BeforeClass;
+import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -84,6 +86,9 @@ public void tearDown() throws IOException {
     System.setOut(null);
   }
 
+  @Rule
+  public MultipleAttemptsRule multipleAttemptsRule = new MultipleAttemptsRule(3);
+
   @Test
   public void testCreateDocument() throws Exception {
     DocumentManagement.createDocument(