test(dialogflow): deflake and re-enable test cases in ITSystemTest (#13511)

Each of these test cases failed 7/30 times locally without these fixes.
With the fixes applied, tests pass without flakes in 100+ runs.

- detectIntentTest() flaked regularly if the intent created in setUp()
didn't have sufficient time to fully propagate before detectIntent() was
called in the test case. Poll until detectIntent() returns a non-empty
result before proceeding to assertion on the content.

- listContextsTest() flaked if a system context was encountered (see
https://docs.cloud.google.com/dialogflow/es/docs/reference/rest/v2beta1/projects.agent.environments.users.sessions.contexts/patch#path-parameters).
Adjust the flaky assertion to only look for the expected context while
tolerating others that happen to be present.

Fixes #10491

Author: whowes

java-dialogflow/google-cloud-dialogflow/pom.xml

@@ -87,6 +87,11 @@
       <artifactId>google-cloud-core</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.awaitility</groupId>
+      <artifactId>awaitility</artifactId>
+      <scope>test</scope>
+    </dependency>
     <!-- {x-generated-grpc-dependencies-start} -->
     <dependency>
       <groupId>com.google.api.grpc</groupId>

java-dialogflow/google-cloud-dialogflow/src/test/java/com/google/cloud/dialogflow/v2/it/ITSystemTest.java

@@ -15,7 +15,10 @@
  */
 package com.google.cloud.dialogflow.v2.it;
 
+import static com.google.common.collect.Streams.stream;
+import static org.awaitility.Awaitility.await;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 
 import com.google.cloud.ServiceOptions;
 import com.google.cloud.dialogflow.v2.Agent;
@@ -54,10 +57,10 @@
 import com.google.protobuf.Struct;
 import com.google.protobuf.Value;
 import java.io.IOException;
+import java.time.Duration;
 import java.util.UUID;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
-import org.junit.Ignore;
 import org.junit.Test;
 
 public class ITSystemTest {
@@ -259,7 +262,6 @@ public void getIntentTest() {
   }
 
   @Test
-  @Ignore("b/423958346")
   public void detectIntentTest() {
     QueryInput queryInput =
         QueryInput.newBuilder()
@@ -279,22 +281,28 @@ public void detectIntentTest() {
             .setSession(SESSION_NAME.toString())
             .setQueryInput(queryInput)
             .build();
-    DetectIntentResponse response = sessionsClient.detectIntent(request);
-    QueryResult result = response.getQueryResult();
-    assertEquals(EVENT_NAME, result.getQueryText());
-    assertEquals(ACTION_NAME, result.getAction());
-    assertEquals(DEFAULT_LANGUAGE_CODE, result.getLanguageCode());
-    assertEquals(intent.getDisplayName(), result.getIntent().getDisplayName());
+    await()
+        .atMost(Duration.ofSeconds(30))
+        .pollInterval(Duration.ofSeconds(2))
+        .untilAsserted(
+            () -> {
+              DetectIntentResponse response = sessionsClient.detectIntent(request);
+              QueryResult result = response.getQueryResult();
+              assertEquals(EVENT_NAME, result.getQueryText());
+              assertEquals(ACTION_NAME, result.getAction());
+              assertEquals(DEFAULT_LANGUAGE_CODE, result.getLanguageCode());
+              assertEquals(intent.getDisplayName(), result.getIntent().getDisplayName());
+            });
   }
 
   @Test
-  @Ignore("b/423958346")
   public void listContextsTest() {
     ListContextsRequest request =
         ListContextsRequest.newBuilder().setParent(SESSION_NAME.toString()).build();
-    for (Context actualContext : contextsClient.listContexts(request).iterateAll()) {
-      assertEquals(context.getName(), actualContext.getName());
-    }
+    boolean contextNameInActualContext =
+        stream(contextsClient.listContexts(request).iterateAll())
+            .anyMatch(actualContext -> context.getName().equals(actualContext.getName()));
+    assertTrue(contextNameInActualContext);
   }
 
   @Test