# unit-test-scheduled-async

A skill with ready patterns for unit testing Spring @Scheduled and @Async methods: JUnit 5, CompletableFuture, Awaitility, Mockito.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 3700 installs · ★ 363
- Author: giuseppe-trisciuoglio
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/giuseppe-trisciuoglio/developer-kit/tree/HEAD/plugins/developer-kit-java/skills/unit-test-scheduled-async/SKILL.md
- Updated: 2026-09-10
- HTML: https://affpapa.org/en/nevibecode/skills/unit-test-scheduled-async

## What it does

The skill covers unit testing Spring background tasks without waiting for real scheduler intervals. `@Async` and `@Scheduled` methods get called directly, since both annotations are ignored in unit tests and Spring's proxy is bypassed anyway. You check the `CompletableFuture` result with `get(timeout, unit)` and swap dependencies with `@Mock` and `@InjectMocks`.

Inside are five steps, from calling the method straight through to verifying exception paths, plus validation checkpoints and code samples: waiting for completion, race conditions on shared mutable state via Awaitility, execution counts, error handling in async chains. Full examples with Maven and Gradle dependencies live in `references/examples.md`.

The trap worth knowing: self-invocation. Call an `@Async` method from another method in the same class and the Spring proxy never fires, so the code runs synchronously. Your test passes, production breaks. `ThreadPoolTaskScheduler` also gives no ordering guarantee, so asserting task sequence is pointless. Always set a timeout in `atMost()` and in `get()` — a hung test takes the whole suite with it.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add giuseppe-trisciuoglio/developer-kit --skill unit-test-scheduled-async -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/unit-test-scheduled-async/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/unit-test-scheduled-async/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add giuseppe-trisciuoglio/developer-kit --skill unit-test-scheduled-async -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/unit-test-scheduled-async/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add giuseppe-trisciuoglio/developer-kit --skill unit-test-scheduled-async -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/unit-test-scheduled-async/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install giuseppe-trisciuoglio/developer-kit unit-test-scheduled-async
```

2. **Manually: put the files in place**
- File: `.github/skills/unit-test-scheduled-async/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add giuseppe-trisciuoglio/developer-kit --skill unit-test-scheduled-async -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/giuseppe-trisciuoglio/developer-kit --path plugins/developer-kit-java/skills/unit-test-scheduled-async
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/unit-test-scheduled-async/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add giuseppe-trisciuoglio/developer-kit --skill unit-test-scheduled-async -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/giuseppe-trisciuoglio/developer-kit/tree/HEAD/plugins/developer-kit-java/skills/unit-test-scheduled-async/SKILL.md

## When to use it
- test @Scheduled logic without waiting for the cron to fire
- assert a CompletableFuture result from an @Async method with a timeout
- wait for a race condition to settle via Awaitility
- count how many times a background task ran
- verify that an exception inside an async method wraps into ExecutionException

## Example prompts
- write a unit test for the @Async sendEmailAsync method and assert its CompletableFuture
- test the @Scheduled refreshCache method with a mocked repository
- help me test the race condition in BackgroundWorker with Awaitility

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 2bd063147f830f34.

BEGIN THIRD-PARTY FILE 2bd063147f830f34
```text
---
name: unit-test-scheduled-async
description: Provides patterns for unit testing Spring `@Scheduled` and `@Async` methods using JUnit 5, CompletableFuture, Awaitility, and Mockito. Covers mocking task execution and timing, verifying execution counts, testing cron expressions, validating retry behavior, and simulating thread pool behavior. Use when testing background tasks, cron jobs, periodic execution, scheduled tasks, or thread pool behavior.
allowed-tools: Read, Write, Bash, Glob, Grep
---

# Unit Testing `@Scheduled` and `@Async` Methods

## Overview

Patterns for unit testing Spring `@Scheduled` and `@Async` methods with JUnit 5. Test `CompletableFuture` results, use Awaitility for race conditions, mock scheduled task execution, and validate error handling — without waiting for real scheduling intervals.

## When to Use

- Testing `@Scheduled` method logic
- Testing `@Async` method behavior
- Verifying `CompletableFuture` results
- Testing async error handling
- Testing cron expression logic without waiting for actual scheduling
- Validating thread pool behavior and execution counts
- Testing background task logic in isolation

## Instructions

1. **Call `@Async` methods directly** — bypass Spring's async proxy; the annotation is irrelevant in unit tests
2. **Mock dependencies** with `@Mock` and `@InjectMocks` (Mockito)
3. **Wait for completion** — use `CompletableFuture.get(timeout, unit)` or `await().atMost(...).untilAsserted(...)`
4. **Call `@Scheduled` methods directly** — do not wait for cron/fixedRate; the annotation is ignored in unit tests
5. **Test exception paths** — verify `ExecutionException` wrapping on `CompletableFuture.get()`

**Validation checkpoints:**
- After `CompletableFuture.get()`, assert the returned value before verifying mock interactions
- If `ExecutionException` is thrown, check `.getCause()` to identify the root exception
- If Awaitility times out, increase `atMost()` duration or reduce `pollInterval()` until the condition is reachable
- After multiple task invocations, assert execution counts before `verify()` calls

## Examples
```
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First 2113 of 5851 bytes. © giuseppe-trisciuoglio · MIT · https://github.com/giuseppe-trisciuoglio/developer-kit/tree/HEAD/plugins/developer-kit-java/skills/unit-test-scheduled-async/SKILL.md

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