Unit Testing JSON Serialization with @JsonTest

Overview

Provides patterns for unit testing JSON serialization and deserialization using Spring's @JsonTest and Jackson. Covers POJO mapping, custom serializers, field name mappings, nested objects, date/time formatting, and polymorphic types.

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