Type-safe test fixture generation with a composable, declarative API for building complex object graphs, nested overrides, sealed/enum/null handling, annotation-driven auto-registration, and testing-framework integration.
Kofixture is a Kotlin Multiplatform library for generating type-safe test fixtures. It removes boilerplate from test setup with a composable, declarative API for producing arbitrarily complex object graphs — including nested types, enums, sealed hierarchies, and nullables.
| Artifact | Targets | Description |
|---|---|---|
kofixture-core |
JVM, JS, Native | Core fixture generation engine |
kofixture-kotest-arb |
JVM, JS, Native | Kotest Arb<T> integration |
kofixture-kotest |
JVM, JS, Native | Kotest spec base classes and lifecycle listener |
kofixture-ksp |
JVM | KSP processor — auto-generates fixture registrations |
1. Annotate a companion object to generate a fixture module:
// src/test/kotlin/com/example/Fixtures.kt
@Kofixture(packages = ["com.example"])
object FixturesKSP generates a fixtures property containing all generators for User, Address, etc.
2. Write tests using a spec base class:
class UserTest : KofixtureFunSpec({
val user by sample<User> { name = "Alice" }
val profile by sample<Profile> {
user { name = "Bob" }
user { name { arbitrary { "Bob" } } }
address { city = "Warsaw" }
}
test("overrides name") { user.name shouldBe "Alice" }
test("overrides nested type") { profile.user.name shouldBe "Bob" }
}) {
override val fixtureModules = listOf(fixtures)
}Nested overrides support const values plus Generator/Arb lambdas on child fields.
Delegates (sample<T>, generator<T>, arb<T>) are resolved fresh per test via property delegation.
val registry = buildRegistry {
register<String> { Generator { random -> "str-${random.nextInt(100_000)}" } }
register<User> { User(next<String>(), next<Int>()) }
}
val user: User = registry.sample()
val named: User = registry.sample { name = "Alice" }// build.gradle.kts
testImplementation("io.github.kofixture:kofixture-core:0.1.2")
// + Kotest integration (pick one or both)
testImplementation("io.github.kofixture:kofixture-kotest-arb:0.1.2")
testImplementation("io.github.kofixture:kofixture-kotest:0.1.2")
// + KSP processor (auto-generates fixture modules from annotated objects)
kspTest("io.github.kofixture:kofixture-ksp:0.1.2")// settings.gradle.kts
pluginManagement {
plugins {
id("com.google.devtools.ksp") version "2.3.6"
}
}Artifacts are published to Maven Central — no extra repository configuration needed.
See CONTRIBUTING.md. License: Apache-2.0.
Kofixture is a Kotlin Multiplatform library for generating type-safe test fixtures. It removes boilerplate from test setup with a composable, declarative API for producing arbitrarily complex object graphs — including nested types, enums, sealed hierarchies, and nullables.
| Artifact | Targets | Description |
|---|---|---|
kofixture-core |
JVM, JS, Native | Core fixture generation engine |
kofixture-kotest-arb |
JVM, JS, Native | Kotest Arb<T> integration |
kofixture-kotest |
JVM, JS, Native | Kotest spec base classes and lifecycle listener |
kofixture-ksp |
JVM | KSP processor — auto-generates fixture registrations |
1. Annotate a companion object to generate a fixture module:
// src/test/kotlin/com/example/Fixtures.kt
@Kofixture(packages = ["com.example"])
object FixturesKSP generates a fixtures property containing all generators for User, Address, etc.
2. Write tests using a spec base class:
class UserTest : KofixtureFunSpec({
val user by sample<User> { name = "Alice" }
val profile by sample<Profile> {
user { name = "Bob" }
user { name { arbitrary { "Bob" } } }
address { city = "Warsaw" }
}
test("overrides name") { user.name shouldBe "Alice" }
test("overrides nested type") { profile.user.name shouldBe "Bob" }
}) {
override val fixtureModules = listOf(fixtures)
}Nested overrides support const values plus Generator/Arb lambdas on child fields.
Delegates (sample<T>, generator<T>, arb<T>) are resolved fresh per test via property delegation.
val registry = buildRegistry {
register<String> { Generator { random -> "str-${random.nextInt(100_000)}" } }
register<User> { User(next<String>(), next<Int>()) }
}
val user: User = registry.sample()
val named: User = registry.sample { name = "Alice" }// build.gradle.kts
testImplementation("io.github.kofixture:kofixture-core:0.1.2")
// + Kotest integration (pick one or both)
testImplementation("io.github.kofixture:kofixture-kotest-arb:0.1.2")
testImplementation("io.github.kofixture:kofixture-kotest:0.1.2")
// + KSP processor (auto-generates fixture modules from annotated objects)
kspTest("io.github.kofixture:kofixture-ksp:0.1.2")// settings.gradle.kts
pluginManagement {
plugins {
id("com.google.devtools.ksp") version "2.3.6"
}
}Artifacts are published to Maven Central — no extra repository configuration needed.
See CONTRIBUTING.md. License: Apache-2.0.