test(samples): prevent failure in nightly run by adding retry (#392)

Fixes #381  ☕️

Author: munkhuushmgl

vision/snippets/pom.xml

@@ -63,6 +63,13 @@
       <version>4.13.2</version>
       <scope>test</scope>
     </dependency>
+    <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>com.google.truth</groupId>
       <artifactId>truth</artifactId>

vision/snippets/src/test/java/com/example/vision/DetectIT.java

@@ -23,11 +23,13 @@
 import com.google.cloud.storage.Storage;
 import com.google.cloud.storage.Storage.BlobListOption;
 import com.google.cloud.storage.StorageOptions;
+import com.google.cloud.testing.junit4.MultipleAttemptsRule;
 import java.io.ByteArrayOutputStream;
 import java.io.PrintStream;
 import java.util.UUID;
 import org.junit.After;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -58,6 +60,9 @@ public void tearDown() {
     System.setOut(originalPrintStream);
   }
 
+  @Rule
+  public MultipleAttemptsRule multipleAttemptsRule = new MultipleAttemptsRule(3);
+  
   @Test
   public void testDocumentText() throws Exception {
     // Act