# Automated testing

> Confidence at speed


Encore provides built-in testing tools that make it simple to test your application using a variety of test runners.

To run tests with Encore:

1. Configure the `test` command in your `package.json` to use the test runner of your choice.
2. Configure your test runner.
3. Run `encore test` from the CLI.

The `encore test` command automatically sets up all necessary infrastructure in test mode before running your tests.

<GitHubLink 
    href="https://github.com/encoredev/examples/tree/main/ts/uptime" 
    desc="Uptime monitoring app with API endpoint unit tests written in Vitest." 
/>

## Recommended Setup: Vitest

We recommend [Vitest](https://vitest.dev) as your test runner because it offers:
- Fast execution
- Native ESM and TypeScript support
- Jest API compatibility

### Setting up Vitest

1. Create `vite.config.ts` in your application's root directory:

```ts
/// <reference types="vitest" />
import { defineConfig } from "vite";
import path from "path";

export default defineConfig({
  resolve: {
    alias: {
      "~encore": path.resolve(__dirname, "./encore.gen"),
    },
  },
});
```

2. Update your `package.json` to include:

```json
{
  "scripts": {
    "test": "vitest"
  }
}
```

You're done! Now you can run your tests with `encore test`.

### Optional: IDE Integration

#### VS Code Setup

If using Vitest, follow these steps:
1. Install the official Vitest VS Code extension
2. Add to `.vscode/settings.json`:

```json
{
  "vitest.commandLine": "encore test"
}
```

As of Vitest plugin version 0.5 ([issue](https://github.com/vitest-dev/vscode/issues/306)), environment configuration requires an updated approach. The following configuration is required to ensure proper functionality:

Update `settings.json` to include:

```json
"vitest.nodeEnv": {
    // generated with `encore daemon env | grep ENCORE_RUNTIME_LIB | cut -d'=' -f2`
    "ENCORE_RUNTIME_LIB": "/opt/homebrew/Cellar/encore/1.44.5/libexec/runtimes/js/encore-runtime.node"
}
```

When running tests within VSCode, file-level parallel execution must be disabled. Update your `vite.config.ts` as follows:

```typescript
// File vite.config.ts
export default defineConfig({
  resolve: {
    alias: {
      "~encore": path.resolve(__dirname, "./encore.gen"),
    },
  },
  test: {
    fileParallelism: false,
  },
});
```

To improve the performance in CI, you can re-enable the parallel execution by overwriting the config in cli `encore test --fileParallelism=true`.

## Integration Testing Best Practices

Encore applications typically focus on integration tests rather than unit tests because:

- Encore eliminates most boilerplate code
- Your code primarily consists of business logic involving databases and inter-service API calls
- Integration tests better verify this type of functionality

### Test Environment Benefits

When running tests, Encore automatically:
- Sets up separate test databases
- Configures databases for optimal test performance by:
  - Skipping `fsync`
  - Using in-memory filesystems
  - Removing durability overhead

These optimizations make integration tests nearly as fast as unit tests.