# unit-test-controller-layer

Generates isolated MockMvc unit tests for Spring REST controllers with Mockito. Helps verify HTTP status codes, payload validation, and JsonPath assertions.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 3800 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-controller-layer/SKILL.md
- Updated: 2026-09-10
- HTML: https://affpapa.org/en/nevibecode/skills/unit-test-controller-layer

## What it does

The skill provides patterns to test Spring `@RestController` and `@Controller` classes. It relies on `MockMvcBuilders.standaloneSetup` for isolation, combining `@Mock` services with `@InjectMocks` on the controller instance. The instructions cover GET, POST, PUT, and DELETE methods alongside custom headers, path variables, query parameters, and content negotiation.

When assertions fail, the debugging workflow suggests adding `.andDo(print())` to check the actual response against expectations before editing assertions. Projects must include `spring-boot-starter-test` in their Maven or Gradle configuration to compile these test files.

Because standalone MockMvc isolates the web layer with mocked dependencies, this skill validates HTTP-level handling rather than end-to-end business logic in your service beans.

## Install

### Claude Code (native platform)

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

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

### Codex

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

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

### Cursor

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

2. **Manually: put the files in place**
- File: `.cursor/skills/unit-test-controller-layer/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-controller-layer
```

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

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add giuseppe-trisciuoglio/developer-kit --skill unit-test-controller-layer -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-controller-layer
```

### Windsurf (Devin Desktop)

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

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add giuseppe-trisciuoglio/developer-kit --skill unit-test-controller-layer -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-controller-layer/SKILL.md

## When to use it
- generate isolated Spring MVC controller tests using standalone MockMvc setup
- assert response payloads and JSON structures with JsonPath expressions
- test HTTP 400 Bad Request responses on invalid request body payloads
- verify exception mapping to HTTP 404 or 500 error status codes

## Example prompts
- Write a standalone MockMvc unit test for UserController covering all status codes
- Generate a POST test with invalid payload asserting 400 Bad Request and print() on failure
- Add MockMvc assertions for response headers and query parameters in UserControllerTest

## 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: 67c279cf98f56c33.

BEGIN THIRD-PARTY FILE 67c279cf98f56c33
````text
---
name: unit-test-controller-layer
description: Provides patterns for unit testing REST controllers using MockMvc and @WebMvcTest. Generates controller tests that validates request/response mapping, validation, exception handling, and HTTP status codes. Use when testing web layer endpoints in isolation for API endpoint testing, Spring MVC tests, mock HTTP requests, or controller layer unit tests.
allowed-tools: Read, Write, Bash, Glob, Grep
---

# Unit Testing REST Controllers with MockMvc

## Overview

Provides patterns for unit testing `@RestController` and `@Controller` classes using MockMvc. Covers request/response handling, HTTP status codes, request parameter binding, validation, content negotiation, response headers, and exception handling with mocked service dependencies.

## When to Use

Use for: controller tests, API endpoint testing, Spring MVC tests, mock HTTP requests, unit testing web layer endpoints, verifying REST controllers in isolation.

## Instructions

1. **Setup standalone MockMvc**: `MockMvcBuilders.standaloneSetup(controller)` for isolated testing
2. **Mock service dependencies**: Use `@Mock` for all services, `@InjectMocks` for the controller
3. **Test HTTP methods**: GET, POST, PUT, PATCH, DELETE with correct status codes
4. **Validate responses**: JsonPath assertions for JSON, content matchers for body
5. **Test validation**: Send invalid input, verify 400 status with error details
6. **Test errors**: Verify 404, 400, 401, 403, 500 for appropriate conditions
7. **Validate headers**: Both request (Authorization) and response headers
8. **Test content negotiation**: Different Accept and Content-Type headers

### Validation Workflow

```
Run test → If fails: add .andDo(print()) → Check actual vs expected → Fix assertion
```

## Examples

### Maven / Gradle Dependencies

```xml
<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-test</artifactId>
  <scope>test</scope>
</dependency>
```

### Basic Pattern: GET Endpoint

```java
import static org.mockito.Mockito.*;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;

@ExtendWith(MockitoExtension.class)
class UserControllerTest {

  @Mock
  private UserService userService;

  @InjectMocks
  private UserController userController;
````
END THIRD-PARTY FILE 67c279cf98f56c33

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First 2403 of 7574 bytes. © giuseppe-trisciuoglio · MIT · https://github.com/giuseppe-trisciuoglio/developer-kit/tree/HEAD/plugins/developer-kit-java/skills/unit-test-controller-layer/SKILL.md

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---
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