unit-test-json-serialization

Unit testing JSON serialization and deserialization with Spring's @JsonTest and Jackson.

giuseppe-trisciuoglio/developer-kit|Updated Apr 8, 2026

Works with

Claude CodeCursorClineWindsurfCodexGoose

What it does

Covers serialization/deserialization of POJOs, custom serializers/deserializers, field name mappings with @JsonProperty , and null handling using JacksonTester for type-safe assertions
Includes patterns for testing nested objects, lists, date/time formatting, and polymorphic types with @JsonTypeInfo
Provides Maven and Gradle setup, best practices for avoiding circular references and null inclusio

Repository

giuseppe-trisciuoglio/developer-kit

Last updated

Apr 8, 2026

Installation Guide

Select your AI agent

How to use unit-test-json-serialization on Cursor

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Prerequisites

Before installing skills in Cursor, ensure your development environment meets these requirements:

›Cursor installed and configured on your machine
›Node.js 16+ with npm — verify with node --version
›Active project directory where you want to add unit-test-json-serialization

Run the install command

Execute the skills CLI command in your project's root directory to begin installation:

$npx skills add https://github.com/giuseppe-trisciuoglio/developer-kit --skill unit-test-json-serialization

Fetches unit-test-json-serialization from giuseppe-trisciuoglio/developer-kit and configures it for Cursor.

Select Cursor when prompted

The CLI shows a list of agents. Use arrow keys and space to select Cursor:

◆ Which agents do you want to install to?

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│ ── Universal (.agents/skills) ────────────────

│ · Cline · Codex · Goose · Windsurf

│ ●Cursor(selected)

│ · Cursor · Aider · Continue

Verify installation

Confirm successful installation by checking the skill directory location:

.cursor/skills/unit-test-json-serialization

Restart Cursor to activate unit-test-json-serialization. Access via /unit-test-json-serialization in your agent's command palette.

⚠

Security Notice

We perform automated surface-level scans (Gen AI Scanner, Socket, Snyk) during installation. These checks detect common vulnerabilities but do not guarantee complete security. Always review skill source code and verify the publisher's reputation before production use.

Skills execute code in your environment. Always review source, verify the publisher, and test in isolation before production.

›View source on GitHub ›Skills CLI docs ›About Cursor ›What are agent skills?

Documentation

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Use Cases

Task Automation & Efficiency

Automate repetitive workflows and reduce manual effort

Example

Generate reports, summarize documents, draft communications

✓

Save 3-5 hours per week on routine tasks

Knowledge Enhancement

Learn new skills, understand complex topics, get expert guidance

Example

Explain concepts, provide examples, suggest learning resources

✓

Accelerate learning and skill development by 2x

Quality Improvement

Enhance output quality through reviews, suggestions, and refinements

Example

Review drafts, suggest improvements, catch errors

✓

Improve work quality by 30-40% with less effort

When to Use

Testing JSON serialization/deserialization of DTOs

Verifying custom Jackson serializers/deserializers

Validating @JsonProperty, @JsonIgnore, and field name mappings

Testing date/time format handling (LocalDateTime, Date)

Testing null handling and missing fields

Testing polymorphic type deserialization

Instructions

Annotate test class with @JsonTest → Enables JacksonTester auto-configuration

Autowire JacksonTester for target type → Provides type-safe JSON assertions

Test serialization → Call json.write(object) and assert JSON paths with extractingJsonPath*

Test deserialization → Call json.parse(json) or json.parseObject(json) and assert object state

Validate round-trip → Serialize, then deserialize, verify same data (if object is properly comparable)

Test edge cases → Null values, missing fields, empty collections, invalid JSON

Add validation checkpoints: After each assertion, verify the test fails meaningfully with wrong data

Examples

Maven Setup

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

Gradle Setup

dependencies { implementation("org.springframework.boot:spring-boot-starter-json") testImplementation("org.springframework.boot:spring-boot-starter-test") }

Basic Serialization and Deserialization

@JsonTest class UserDtoJsonTest { @Autowired private JacksonTester<UserDto> json; @Test void shouldSerializeUserToJson() throws Exception { UserDto user = new UserDto(1L, "Alice", "[email protected]", 25); JsonContent<UserDto> result = json.write(user); result .extractingJsonPathNumberValue("$.id").isEqualTo(1) .extractingJsonPathStringValue("$.name").isEqualTo("Alice") .extractingJsonPathStringValue("$.email").isEqualTo("[email protected]") .extractingJsonPathNumberValue("$.age").isEqualTo(25); } @Test void shouldDeserializeJsonToUser() throws Exception { String json_content = "{\"id\":1,\"name\":\"Alice\",\"email\":\"[email protected]\",\"age\":25}"; UserDto user = json.parse(json_content).getObject(); assertThat(user.getId()).isEqualTo(1L); assertThat(user.getName()).isEqualTo("Alice"); assertThat(user.getEmail()).isEqualTo("[email protected]"); assertThat(user.getAge()).isEqualTo(25); } @Test void shouldHandleNullFields() throws Exception { String json_content = "{\"id\":1,\"name\":null,\"email\":\"[email protected]\"}"; UserDto user = json.parse(json_content).getObject(); assertThat(user.getName()).isNull(); } }

Custom JSON Properties

public class Order { @JsonProperty("order_id") private Long id; @JsonProperty("total_amount") private BigDecimal amount; @JsonIgnore private String internalNote; } @JsonTest class OrderJsonTest { @Autowired private JacksonTester<Order> json; @Test void shouldMapJsonPropertyNames() throws Exception { String json_content = "{\"order_id\":123,\"total_amount\":99.99}"; Order order = json.parse(json_content).getObject(); assertThat(order.getId()).isEqualTo(123L); assertThat(order.getAmount()).isEqualByComparingTo(new BigDecimal("99.99")); } @Test void shouldIgnoreJsonIgnoreFields() throws Exception { Order order = new Order(123L, new BigDecimal("99.99")); order.setInternalNote("Secret"); assertThat(json.write(order).json).doesNotContain("internalNote"); } }

Nested Objects

public class Product { private Long id; private String name; private Category category; private List<Review> reviews; } @JsonTest class ProductJsonTest { @Autowired

unit-test-json-serialization

What it does

Category

Repository

Last updated

Installation Guide

How to use unit-test-json-serialization on Cursor

Prerequisites

Run the install command

Select Cursor when prompted

Verify installation

Security Notice

Documentation

List & Monetize Your Skill

Use Cases

Task Automation & Efficiency

Knowledge Enhancement

Quality Improvement

Install Skill

Unit Testing JSON Serialization with @JsonTest

Overview

When to Use

Instructions

Examples

Maven Setup

Gradle Setup

Basic Serialization and Deserialization

Custom JSON Properties

Nested Objects

Implementation Guide

Best Practices

When to Use This

Learning Path

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Reviews

Discussion

Unit Testing JSON Serialization with `@JsonTest`

`Implementation Guide`

`Best Practices`

`When to Use This`

`Learning Path`

`Related Skills`

`Reviews`

`Discussion`