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unit-test-mapper-converter SKILL.md skillA

unit-test-mapper-converter from giuseppe-trisciuoglio/developer-kit is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

Install it, pinned

mdr add giuseppe-trisciuoglio/developer-kit/unit-test-mapper-converter@git:20260324.a02e282

Pins git:20260324.a02e282 in mdr.lock. Pin the fingerprint instead.

Audit grade: A, 17 of 17 checks passed
Kind: SKILL.md skill
Repository: giuseppe-trisciuoglio/developer-kit
Path: plugins/developer-kit-java/skills/unit-test-mapper-converter/SKILL.md
Versions recorded: 5
Latest version: git:20260324.a02e282, committed Mar 24, 2026
First version recorded: Feb 7, 2026
Size: 4,961 bytes
Repository stars: 367
License: MIT

Provides patterns for unit testing mappers, converters, and bean mappings. Validates entity-to-DTO and model transformation logic in isolation. Generates executable mapping tests with MapStruct and custom converter test coverage. Use when writing mapping tests, converter tests, entity mapping tests, or ensuring correct data transformation between DTOs and domain objects.

Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.

What the file says

# Unit Testing Mappers and Converters

## Overview

Provides patterns for unit testing MapStruct mappers and custom converter classes. Covers field mapping accuracy, null handling, type conversions, nested object transformations, bidirectional mapping, enum mapping, and partial updates.

## When to Use

- Writing mapping tests for MapStruct mapper implementations
- Testing custom entity-to-DTO converters and bean mappings
- Validating nested object mapping and collection transformations

## Instructions

### 1. Validate Generated Mapper Classes
Before testing, verify generated mapper classes exist:
```bash
# Maven
ls target/generated-sources/

# Gradle
ls build/generated/sources/
```

**If generated classes are missing:**
1. Run `mvn compile` (Maven) or `./gradlew compileJava` (Gradle)
2. Check that the MapStruct annotation processor is configured
3. Verify `@Mapper` interfaces are in a compiled source set

### 2. Test Null Handling
```java
assertThat(mapper.toDto(null)).isNull();
```
Configure `nullValueMappingStrategy` in mapper if null should return empty/default.

**If null tests fail:**
1. Add `nullValueMappingStrategy = NullValueMappingStrategy.RETURN_NULL` to `@Mapper`
…

Read the whole file at its exact version.

How to install

The exact contents, by fingerprint

mdr add giuseppe-trisciuoglio/developer-kit/unit-test-mapper-converter@sha256:2f9f1b8f91b3932b

The line at the top of this page pins the label git:20260324.a02e282, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.

Badge

[![mdr](https://markdownregistry.com/badge/art_v3hrtzo6ypttjuqn.svg)](https://markdownregistry.com/a/art_v3hrtzo6ypttjuqn)

5 badge image fetches in 30 days. What the badge shows.

Versions

The registry has recorded 5 versions of this file, between Feb 7, 2026 and Mar 24, 2026, about one every 11 days.

version	committed	commit	size	audit
git:20260324.a02e282 latest	2026-03-24	a02e282	4,961 B	A	view · diff
git:20260316.91dc3c4	2026-03-16	91dc3c4	13,158 B	A	view · diff
git:20260223.c6d4db1	2026-02-23	c6d4db1	13,146 B	A	view · diff
v1.0.1	2026-02-08	147afce	13,238 B	A	view · diff
v1.0.1	2026-02-07	1a732c7	11,571 B	A	view

Audit of the latest version

A 17 of 17 checks passed. Fixed automatic checks with no AI involved, so the same checks give the same answer every run.

pass: Frontmatter block present
pass: Frontmatter declares a name
pass: Frontmatter declares a description
pass: Size between 200 bytes and 200 KB (4961 bytes)
pass: No zero-width or bidi control characters
pass: No instruction hidden inside an HTML comment
pass: No link to an exfiltration or paste host
pass: No credential-shaped string
pass: No instruction to send local credentials anywhere
pass: No text hidden with inline styles
pass: No prompt-injection phrasing
pass: No curl or wget piped into a shell
pass: No recursive delete of root, home or parent
pass: No instruction to read or print local credentials
pass: No base64 blob over 200 characters
pass: No link to a raw IP address
pass: No script tag

Source

GitHub

giuseppe-trisciuoglio/developer-kit · 367 stars · license MIT · pushed 2026-09-10 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_v3hrtzo6ypttjuqn
GET https://markdownregistry.com/api/v1/resolve?ref=giuseppe-trisciuoglio/developer-kit/unit-test-mapper-converter
GET https://markdownregistry.com/api/v1/blob/2f9f1b8f91b3932b3feda6df421ec542835688dbc18bf54aaa4de3f211b4cc12

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Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.

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