Features
Quick reference of all Fakt capabilities.
Supported Class Types
| Case | Example |
|---|
| Interfaces |
@Fake
interface UserRepository {
suspend fun getUser(id: String): User
}
|
| Abstract Classes |
@Fake
abstract class BaseService {
abstract fun start(): Boolean
}
|
| Open Classes |
@Fake
open class NetworkClient {
open suspend fun fetch(url: String): Result<String>
}
|
| Data Classes |
❌ Can't be faked
✅ Works as parameter/return types
|
| Sealed Classes |
❌ Can't be faked
✅ Works as parameter/return types
|
Type System
| Case | Example |
|---|
| Class-Level Generics |
val fake = fakeRepository<User> {
save { item -> Result.success(Unit) }
}
|
| Method-Level Generics |
fun <T, R> transform(input: T, mapper: (T) -> R): R
|
| Generic Constraints |
interface ComparableRepository<T : Comparable<T>> {
fun findMax(items: List<T>): T?
}
|
| Variance |
interface Producer<out T>
interface Consumer<in T>
|
| Nullable Types |
fun findUser(id: String): User? // Default: null
|
| Result Types |
fun save(): Result<Unit> // Default: Result.failure(...)
|
| Collections |
fun getAll(): List<User> // Default: emptyList()
|
Language Features
| Case | Example |
|---|
| Suspend Functions |
suspend fun fetch(): User // Works in runTest { }
|
| Properties (val) |
val apiUrl: String // fake.apiUrl + fake.apiUrlCallCount
|
| Properties (var) |
var theme: String // getThemeCallCount + setThemeCallCount
|
| Inheritance |
interface UserRepo : BaseRepo { ... } // Inherits parent methods
|
| Default Parameters |
fun log(msg: String, level: LogLevel = INFO)
|
Call Tracking
| Case | Example |
|---|
| StateFlow Counters |
fake.trackCallCount.value // Thread-safe Int counter
|
| Reactive Testing |
fake.trackCallCount.test { awaitItem() shouldBe 1 } // Turbine
|
| Property Tracking |
fake.getThemeCallCount
fake.setThemeCallCount
|
| Thread Safety |
All counters use `MutableStateFlow.update` for thread-safe operations.
|
Code Generation
| Case | Example |
|---|
| Factory Functions |
fakeUserRepository { getUser { id -> User(id, "Alice") } }
|
| Type-Safe DSL |
Compiler catches type errors at build time.
|
| Smart Defaults |
- String →
""
- Int →
0
- Boolean →
false
- List →
emptyList()
|
Multi-Module (Experimental)
| Case | Example |
|---|
| Collector Module |
fakt {
@OptIn(ExperimentalFaktMultiModule::class)
collectFakesFrom(projects.core.analytics)
}
|
| Consumer Module |
dependencies {
commonTest {
implementation(projects.core.analyticsFakes)
}
}
|
| Case | Example |
|---|
| All KMP Targets |
✅ JVM, Android, iOS, macOS, Linux, Windows, JS, WASM, watchOS, tvOS
|
| Single Platform |
✅ JVM-only, Android-only projects fully supported
|
Next Steps