chore: Add test to verify workflow reconnection logic (#1692)

Signed-off-by: Javier Aliaga <javier@diagrid.io>

Author: javier-aliaga

durabletask-client/src/test/java/io/dapr/durabletask/DurableTaskGrpcWorkerReconnectTest.java

@@ -0,0 +1,205 @@
+/*
+ * Copyright 2026 The Dapr Authors
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.dapr.durabletask;
+
+import io.dapr.durabletask.implementation.protobuf.OrchestratorService;
+import io.dapr.durabletask.implementation.protobuf.TaskHubSidecarServiceGrpc;
+import io.grpc.ManagedChannel;
+import io.grpc.Server;
+import io.grpc.Status;
+import io.grpc.inprocess.InProcessChannelBuilder;
+import io.grpc.inprocess.InProcessServerBuilder;
+import io.grpc.stub.StreamObserver;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * Tests that DurableTaskGrpcWorker auto-heals (reconnects) when the gRPC
+ * connection to the sidecar drops with UNAVAILABLE or CANCELLED status.
+ *
+ * @see <a href="https://github.com/dapr/java-sdk/issues/1652">Issue #1652</a>
+ */
+class DurableTaskGrpcWorkerReconnectTest {
+
+  private DurableTaskGrpcWorker worker;
+  private Server server;
+  private ManagedChannel channel;
+
+  @AfterEach
+  void tearDown() throws Exception {
+    if (worker != null) {
+      worker.close();
+    }
+    if (channel != null) {
+      channel.shutdownNow().awaitTermination(5, TimeUnit.SECONDS);
+    }
+    if (server != null) {
+      server.shutdownNow().awaitTermination(5, TimeUnit.SECONDS);
+    }
+  }
+
+  @Test
+  void workerReconnectsAfterUnavailableError() throws Exception {
+    int requiredCalls = 3;
+    CountDownLatch latch = new CountDownLatch(requiredCalls);
+    AtomicInteger callCount = new AtomicInteger(0);
+
+    String serverName = InProcessServerBuilder.generateName();
+    server = InProcessServerBuilder.forName(serverName)
+        .directExecutor()
+        .addService(new TaskHubSidecarServiceGrpc.TaskHubSidecarServiceImplBase() {
+          @Override
+          public void getWorkItems(
+              OrchestratorService.GetWorkItemsRequest request,
+              StreamObserver<OrchestratorService.WorkItem> responseObserver) {
+            callCount.incrementAndGet();
+            latch.countDown();
+            // Simulate sidecar being unavailable
+            responseObserver.onError(Status.UNAVAILABLE
+                .withDescription("Sidecar is unavailable")
+                .asRuntimeException());
+          }
+        })
+        .build()
+        .start();
+
+    channel = InProcessChannelBuilder.forName(serverName).directExecutor().build();
+
+    worker = new DurableTaskGrpcWorkerBuilder()
+        .grpcChannel(channel)
+        .build();
+    worker.start();
+
+    // The worker should retry multiple times after UNAVAILABLE errors.
+    // With a 5-second retry delay, we wait long enough for at least 3 attempts.
+    boolean reached = latch.await(30, TimeUnit.SECONDS);
+    assertTrue(reached,
+        "Expected at least " + requiredCalls + " getWorkItems calls (reconnect attempts), but got " + callCount.get());
+  }
+
+  @Test
+  void workerReconnectsAfterCancelledError() throws Exception {
+    int requiredCalls = 2;
+    CountDownLatch latch = new CountDownLatch(requiredCalls);
+    AtomicInteger callCount = new AtomicInteger(0);
+
+    String serverName = InProcessServerBuilder.generateName();
+    server = InProcessServerBuilder.forName(serverName)
+        .directExecutor()
+        .addService(new TaskHubSidecarServiceGrpc.TaskHubSidecarServiceImplBase() {
+          @Override
+          public void getWorkItems(
+              OrchestratorService.GetWorkItemsRequest request,
+              StreamObserver<OrchestratorService.WorkItem> responseObserver) {
+            callCount.incrementAndGet();
+            latch.countDown();
+            // Simulate connection cancelled (e.g., sidecar restart)
+            responseObserver.onError(Status.CANCELLED
+                .withDescription("Connection cancelled")
+                .asRuntimeException());
+          }
+        })
+        .build()
+        .start();
+
+    channel = InProcessChannelBuilder.forName(serverName).directExecutor().build();
+
+    worker = new DurableTaskGrpcWorkerBuilder()
+        .grpcChannel(channel)
+        .build();
+    worker.start();
+
+    boolean reached = latch.await(30, TimeUnit.SECONDS);
+    assertTrue(reached,
+        "Expected at least " + requiredCalls + " getWorkItems calls after CANCELLED, but got " + callCount.get());
+  }
+
+  @Test
+  void workerReconnectsAfterStreamEndsNormally() throws Exception {
+    int requiredCalls = 2;
+    CountDownLatch latch = new CountDownLatch(requiredCalls);
+    AtomicInteger callCount = new AtomicInteger(0);
+
+    String serverName = InProcessServerBuilder.generateName();
+    server = InProcessServerBuilder.forName(serverName)
+        .directExecutor()
+        .addService(new TaskHubSidecarServiceGrpc.TaskHubSidecarServiceImplBase() {
+          @Override
+          public void getWorkItems(
+              OrchestratorService.GetWorkItemsRequest request,
+              StreamObserver<OrchestratorService.WorkItem> responseObserver) {
+            callCount.incrementAndGet();
+            latch.countDown();
+            // Simulate stream ending normally (server completes without sending items)
+            responseObserver.onCompleted();
+          }
+        })
+        .build()
+        .start();
+
+    channel = InProcessChannelBuilder.forName(serverName).directExecutor().build();
+
+    worker = new DurableTaskGrpcWorkerBuilder()
+        .grpcChannel(channel)
+        .build();
+    worker.start();
+
+    // When the stream ends normally, the outer while(true) loop should
+    // re-establish the stream immediately (no 5s delay for normal completion).
+    boolean reached = latch.await(10, TimeUnit.SECONDS);
+    assertTrue(reached,
+        "Expected at least " + requiredCalls + " getWorkItems calls after normal stream end, but got " + callCount.get());
+  }
+
+  @Test
+  void workerStopsCleanlyOnClose() throws Exception {
+    CountDownLatch firstCallLatch = new CountDownLatch(1);
+
+    String serverName = InProcessServerBuilder.generateName();
+    server = InProcessServerBuilder.forName(serverName)
+        .directExecutor()
+        .addService(new TaskHubSidecarServiceGrpc.TaskHubSidecarServiceImplBase() {
+          @Override
+          public void getWorkItems(
+              OrchestratorService.GetWorkItemsRequest request,
+              StreamObserver<OrchestratorService.WorkItem> responseObserver) {
+            firstCallLatch.countDown();
+            // Keep stream open (simulate connected state)
+            // The worker should be interrupted by close()
+          }
+        })
+        .build()
+        .start();
+
+    channel = InProcessChannelBuilder.forName(serverName).directExecutor().build();
+
+    worker = new DurableTaskGrpcWorkerBuilder()
+        .grpcChannel(channel)
+        .build();
+    worker.start();
+
+    // Wait for the worker to connect
+    assertTrue(firstCallLatch.await(10, TimeUnit.SECONDS), "Worker should have connected");
+
+    // Close should stop the worker cleanly without hanging
+    worker.close();
+    worker = null; // prevent double-close in tearDown
+  }
+}