AggregateSpec

Base class for writing aggregate specification tests using a domain-specific language (DSL).

AggregateSpec provides a declarative way to define comprehensive test scenarios for domain aggregates using the Given/When/Expect pattern. It leverages JUnit 5's dynamic test capabilities to generate multiple test cases from a single specification, including branching scenarios via forks.

This class is designed for behavior-driven development (BDD) style testing of aggregates, allowing complex state transitions and command validations to be expressed fluently.

Key features:

• Declarative test definition using DSL

• Support for branching test scenarios with forks

• Automatic generation of dynamic JUnit 5 tests

• Type-safe aggregate testing with generics

• Integration with dependency injection for mocking services

Example usage:

class CartSpec : AggregateSpec<Cart, CartState>({
    on {
        val addCartItem = AddCartItem(productId = "item1", quantity = 1)
        givenOwnerId("owner123")
        whenCommand(addCartItem) {
            expectNoError()
            expectEventType(CartItemAdded::class)
            expectState { items.assert().hasSize(1) }

            fork("Remove Item") {
                val removeCommand = RemoveCartItem(productIds = setOf("item1"))
                whenCommand(removeCommand) {
                    expectEventType(CartItemRemoved::class)
                    expectState { items.assert().isEmpty() }
                }
            }
        }
    }
})

Parameters