chore: Add tests for ClientTaskManager

client/base/src/main/java/io/a2a/client/ClientTaskManager.java

@@ -115,10 +115,7 @@ public Task saveTaskEvent(TaskArtifactUpdateEvent taskArtifactUpdateEvent) {
      */
     public Task updateWithMessage(Message message, Task task) {
         Task.Builder taskBuilder = Task.builder(task);
-        List<Message> history = task.history();
-        if (history == null) {
-            history = new ArrayList<>();
-        }
+        List<Message> history = new ArrayList<>(task.history());
         if (task.status().message() != null) {
             history.add(task.status().message());
             taskBuilder.status(new TaskStatus(task.status().state(), null, task.status().timestamp()));

client/base/src/test/java/io/a2a/client/ClientTaskManagerTest.java

@@ -0,0 +1,323 @@
+package io.a2a.client;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import io.a2a.spec.A2AClientInvalidArgsError;
+import io.a2a.spec.A2AClientInvalidStateError;
+import io.a2a.spec.Artifact;
+import io.a2a.spec.Message;
+import io.a2a.spec.Task;
+import io.a2a.spec.TaskArtifactUpdateEvent;
+import io.a2a.spec.TaskState;
+import io.a2a.spec.TaskStatus;
+import io.a2a.spec.TaskStatusUpdateEvent;
+import io.a2a.spec.TextPart;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class ClientTaskManagerTest {
+
+    private ClientTaskManager taskManager;
+    private Task sampleTask;
+    private Message sampleMessage;
+
+    @BeforeEach
+    public void setUp() {
+        taskManager = new ClientTaskManager();
+
+        sampleTask = Task.builder()
+                .id("task123")
+                .contextId("context456")
+                .status(new TaskStatus(TaskState.WORKING))
+                .build();
+
+        sampleMessage = Message.builder()
+                .messageId("msg1")
+                .role(Message.Role.USER)
+                .parts(Collections.singletonList(new TextPart("Hello")))
+                .build();
+    }
+
+    @Test
+    public void testGetCurrentTaskNoTaskRaisesError() {
+        A2AClientInvalidStateError exception = assertThrows(
+                A2AClientInvalidStateError.class,
+                () -> taskManager.getCurrentTask()
+        );
+        assertTrue(exception.getMessage().contains("No current task"));
+    }
+
+    @Test
+    public void testSaveTaskEventWithTask() throws Exception {
+        Task result = taskManager.saveTaskEvent(sampleTask);
+
+        assertEquals(sampleTask, taskManager.getCurrentTask());
+        assertEquals(sampleTask, result);
+    }
+
+    @Test
+    public void testSaveTaskEventWithTaskAlreadySetRaisesError() throws Exception {
+        taskManager.saveTaskEvent(sampleTask);
+
+        A2AClientInvalidArgsError exception = assertThrows(
+                A2AClientInvalidArgsError.class,
+                () -> taskManager.saveTaskEvent(sampleTask)
+        );
+        assertTrue(exception.getMessage().contains("Task is already set, create new manager for new tasks."));
+    }
+
+    @Test
+    public void testSaveTaskEventWithStatusUpdate() throws Exception {
+        taskManager.saveTaskEvent(sampleTask);
+
+        TaskStatusUpdateEvent statusUpdate = TaskStatusUpdateEvent.builder()
+                .taskId(sampleTask.id())
+                .contextId(sampleTask.contextId())
+                .status(new TaskStatus(TaskState.COMPLETED, sampleMessage, null))
+                .build();
+
+        Task updatedTask = taskManager.saveTaskEvent(statusUpdate);
+
+        assertEquals(TaskState.COMPLETED, updatedTask.status().state());
+        assertNotNull(updatedTask.history());
+        assertEquals(1, updatedTask.history().size());
+        assertEquals(sampleMessage, updatedTask.history().get(0));
+    }
+
+    @Test
+    public void testSaveTaskEventWithStatusUpdateAndMetadata() throws Exception {
+        taskManager.saveTaskEvent(sampleTask);
+
+        Map<String, Object> metadata = new HashMap<>();
+        metadata.put("key1", "value1");
+        metadata.put("key2", 42);
+
+        TaskStatusUpdateEvent statusUpdate = TaskStatusUpdateEvent.builder()
+                .taskId(sampleTask.id())
+                .contextId(sampleTask.contextId())
+                .status(new TaskStatus(TaskState.WORKING))
+                .metadata(metadata)
+                .build();
+
+        Task updatedTask = taskManager.saveTaskEvent(statusUpdate);
+
+        assertNotNull(updatedTask.metadata());
+        assertEquals("value1", updatedTask.metadata().get("key1"));
+        assertEquals(42, updatedTask.metadata().get("key2"));
+    }
+
+    @Test
+    public void testSaveTaskEventWithArtifactUpdate() throws Exception {
+        taskManager.saveTaskEvent(sampleTask);
+
+        Artifact artifact = Artifact.builder()
+                .artifactId("art1")
+                .parts(Collections.singletonList(new TextPart("artifact content")))
+                .build();
+
+        TaskArtifactUpdateEvent artifactUpdate = TaskArtifactUpdateEvent.builder()
+                .taskId(sampleTask.id())
+                .contextId(sampleTask.contextId())
+                .artifact(artifact)
+                .build();
+
+        Task updatedTask = taskManager.saveTaskEvent(artifactUpdate);
+
+        assertNotNull(updatedTask);
+        assertNotNull(updatedTask.artifacts());
+        assertEquals(1, updatedTask.artifacts().size());
+        assertEquals("art1", updatedTask.artifacts().get(0).artifactId());
+    }
+
+    @Test
+    public void testSaveTaskEventCreatesTaskIfNotExists() throws Exception {
+        TaskStatusUpdateEvent statusUpdate = TaskStatusUpdateEvent.builder()
+                .taskId("new_task")
+                .contextId("new_context")
+                .status(new TaskStatus(TaskState.WORKING))
+                .build();
+
+        Task updatedTask = taskManager.saveTaskEvent(statusUpdate);
+
+        assertNotNull(updatedTask);
+        assertEquals("new_task", updatedTask.id());
+        assertEquals("new_context", updatedTask.contextId());
+        assertEquals(TaskState.WORKING, updatedTask.status().state());
+    }
+
+    @Test
+    public void testSaveTaskEventCreatesTaskFromArtifactUpdateIfNotExists() {
+        Artifact artifact = Artifact.builder()
+                .artifactId("art1")
+                .parts(Collections.singletonList(new TextPart("artifact content")))
+                .build();
+
+        TaskArtifactUpdateEvent artifactUpdate = TaskArtifactUpdateEvent.builder()
+                .taskId("new_task_id")
+                .contextId("new_context_id")
+                .artifact(artifact)
+                .build();
+
+        Task updatedTask = taskManager.saveTaskEvent(artifactUpdate);
+
+        assertNotNull(updatedTask);
+        assertEquals("new_task_id", updatedTask.id());
+        assertEquals("new_context_id", updatedTask.contextId());
+        assertNotNull(updatedTask.artifacts());
+        assertEquals(1, updatedTask.artifacts().size());
+    }
+
+    @Test
+    public void testUpdateWithMessage() {
+        // Use a task with mutable history list initialized properly
+        Task taskWithHistory = Task.builder()
+                .id("task123")
+                .contextId("context456")
+                .status(new TaskStatus(TaskState.WORKING))
+                .build();
+
+        Task updatedTask = taskManager.updateWithMessage(sampleMessage, taskWithHistory);
+
+        assertNotNull(updatedTask.history());
+        assertEquals(1, updatedTask.history().size());
+        assertEquals(sampleMessage, updatedTask.history().get(0));
+    }
+
+    @Test
+    public void testUpdateWithMessageMovesStatusMessage() {
+        Message statusMessage = Message.builder()
+                .messageId("status_msg")
+                .role(Message.Role.AGENT)
+                .parts(Collections.singletonList(new TextPart("Status")))
+                .build();
+
+        Task taskWithStatusMessage = Task.builder()
+                .id("task123")
+                .contextId("context456")
+                .status(new TaskStatus(TaskState.WORKING, statusMessage, null))
+                .build();
+
+        Task updatedTask = taskManager.updateWithMessage(sampleMessage, taskWithStatusMessage);
+
+        assertNotNull(updatedTask.history());
+        assertEquals(2, updatedTask.history().size());
+        assertEquals(statusMessage, updatedTask.history().get(0));
+        assertEquals(sampleMessage, updatedTask.history().get(1));
+        assertNull(updatedTask.status().message());
+    }
+
+    @Test
+    public void testUpdateWithMessagePreservesExistingHistory() {
+        Message existingMessage = Message.builder()
+                .messageId("existing_msg")
+                .role(Message.Role.USER)
+                .parts(Collections.singletonList(new TextPart("Existing")))
+                .build();
+
+        Task taskWithHistory = Task.builder()
+                .id("task123")
+                .contextId("context456")
+                .status(new TaskStatus(TaskState.WORKING))
+                .history(List.of(existingMessage))
+                .build();
+
+        Task updatedTask = taskManager.updateWithMessage(sampleMessage, taskWithHistory);
+
+        assertNotNull(updatedTask.history());
+        assertEquals(2, updatedTask.history().size());
+        assertEquals(existingMessage, updatedTask.history().get(0));
+        assertEquals(sampleMessage, updatedTask.history().get(1));
+    }
+
+    @Test
+    public void testSaveTaskEventMultipleStatusUpdates() throws Exception {
+        taskManager.saveTaskEvent(sampleTask);
+
+        // First status update
+        TaskStatusUpdateEvent statusUpdate1 = TaskStatusUpdateEvent.builder()
+                .taskId(sampleTask.id())
+                .contextId(sampleTask.contextId())
+                .status(new TaskStatus(TaskState.WORKING, sampleMessage, null))
+                .build();
+
+        Task updatedTask1 = taskManager.saveTaskEvent(statusUpdate1);
+        assertEquals(TaskState.WORKING, updatedTask1.status().state());
+        assertEquals(1, updatedTask1.history().size());
+
+        // Second status update
+        Message secondMessage = Message.builder()
+                .messageId("msg2")
+                .role(Message.Role.AGENT)
+                .parts(Collections.singletonList(new TextPart("Second message")))
+                .build();
+
+        TaskStatusUpdateEvent statusUpdate2 = TaskStatusUpdateEvent.builder()
+                .taskId(sampleTask.id())
+                .contextId(sampleTask.contextId())
+                .status(new TaskStatus(TaskState.COMPLETED, secondMessage, null))
+                .build();
+
+        Task updatedTask2 = taskManager.saveTaskEvent(statusUpdate2);
+        assertEquals(TaskState.COMPLETED, updatedTask2.status().state());
+        assertEquals(2, updatedTask2.history().size());
+    }
+
+    @Test
+    public void testSaveTaskEventMultipleArtifactUpdates() throws Exception {
+        taskManager.saveTaskEvent(sampleTask);
+
+        // First artifact update
+        Artifact artifact1 = Artifact.builder()
+                .artifactId("art1")
+                .parts(Collections.singletonList(new TextPart("First artifact")))
+                .build();
+
+        TaskArtifactUpdateEvent artifactUpdate1 = TaskArtifactUpdateEvent.builder()
+                .taskId(sampleTask.id())
+                .contextId(sampleTask.contextId())
+                .artifact(artifact1)
+                .build();
+
+        Task updatedTask1 = taskManager.saveTaskEvent(artifactUpdate1);
+        assertEquals(1, updatedTask1.artifacts().size());
+
+        // Second artifact update
+        Artifact artifact2 = Artifact.builder()
+                .artifactId("art2")
+                .parts(Collections.singletonList(new TextPart("Second artifact")))
+                .build();
+
+        TaskArtifactUpdateEvent artifactUpdate2 = TaskArtifactUpdateEvent.builder()
+                .taskId(sampleTask.id())
+                .contextId(sampleTask.contextId())
+                .artifact(artifact2)
+                .build();
+
+        Task updatedTask2 = taskManager.saveTaskEvent(artifactUpdate2);
+        assertEquals(2, updatedTask2.artifacts().size());
+    }
+
+    @Test
+    public void testSaveTaskEventWithEmptyContextId() throws Exception {
+        TaskStatusUpdateEvent statusUpdate = TaskStatusUpdateEvent.builder()
+                .taskId("task_with_empty_context")
+                .contextId("")
+                .status(new TaskStatus(TaskState.SUBMITTED))
+                .build();
+
+        Task updatedTask = taskManager.saveTaskEvent(statusUpdate);
+
+        assertNotNull(updatedTask);
+        assertEquals("task_with_empty_context", updatedTask.id());
+        assertEquals("", updatedTask.contextId());
+    }
+}