ActorCore provides a straightforward testing framework to build reliable and maintainable applications. This guide covers how to write effective tests for your actor-based services.

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Setup

To set up testing with ActorCore:

# Install Vitest
npm install -D vitest

# Run tests
npm test

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Basic Testing Setup

ActorCore includes a test helper called setupTest that configures a test environment with in-memory drivers for your actors. This allows for fast, isolated tests without external dependencies.

import { test, expect } from "vitest";
import { setupTest } from "actor-core/test";
import { app } from "../src/index";

test("my actor test", async (test) => {
  const { client } = await setupTest(test, app);
  
  // Now you can interact with your actor through the client
  const myActor = await client.myActor.get();
  
  // Test your actor's functionality
  await myActor.someAction();
  
  // Make assertions
  const result = await myActor.getState();
  expect(result).toEqual("updated");
});

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Testing Actor State

The test framework uses in-memory drivers that persist state within each test, allowing you to verify that your actor correctly maintains state between operations.

import { test, expect } from "vitest";
import { setupTest } from "actor-core/test";
import { app } from "../src/index";

test("actor should persist state", async (test) => {
  const { client } = await setupTest(test, app);
  const counter = await client.counter.get();
  
  // Initial state
  expect(await counter.getCount()).toBe(0);
  
  // Modify state
  await counter.increment();
  
  // Verify state was updated
  expect(await counter.getCount()).toBe(1);
});

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Testing Events

For actors that emit events, you can verify events are correctly triggered by subscribing to them:

import { test, expect, vi } from "vitest";
import { setupTest } from "actor-core/test";
import { app } from "../src/index";

test("actor should emit events", async (test) => {
  const { client } = await setupTest(test, app);
  const chatRoom = await client.chatRoom.get();
  
  // Set up event handler with a mock function
  const mockHandler = vi.fn();
  chatRoom.on("newMessage", mockHandler);
  
  // Trigger the event
  await chatRoom.sendMessage("testUser", "Hello world");
  
  // Wait for the event to be emitted
  await vi.waitFor(() => {
    expect(mockHandler).toHaveBeenCalledWith("testUser", "Hello world");
  });
});

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Testing Schedules

ActorCore’s schedule functionality can be tested using Vitest’s time manipulation utilities:

import { test, expect, vi } from "vitest";
import { setupTest } from "actor-core/test";
import { app } from "../src/index";

test("scheduled tasks should execute", async (test) => {
  // setupTest automatically configures vi.useFakeTimers()
  const { client } = await setupTest(test, app);
  const scheduler = await client.scheduler.get();
  
  // Set up a scheduled task
  await scheduler.scheduleTask("reminder", 60000); // 1 minute in the future
  
  // Fast-forward time by 1 minute
  await vi.advanceTimersByTimeAsync(60000);
  
  // Verify the scheduled task executed
  expect(await scheduler.getCompletedTasks()).toContain("reminder");
});

The setupTest function automatically calls vi.useFakeTimers(), allowing you to control time in your tests with functions like vi.advanceTimersByTimeAsync(). This makes it possible to test scheduled operations without waiting for real time to pass.

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Best Practices

  1. Isolate tests: Each test should run independently, avoiding shared state.
  2. Test edge cases: Verify how your actor handles invalid inputs, concurrent operations, and error conditions.
  3. Mock time: Use Vitest’s timer mocks for testing scheduled operations.
  4. Use realistic data: Test with data that resembles production scenarios.

ActorCore’s testing framework automatically handles server setup and teardown, so you can focus on writing effective tests for your business logic.