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Limitations

Known limitations and workarounds.

Current Limitations

❌ Data Classes as @Fake Targets

Data classes have compiler-generated implementations and can’t be faked.

Workaround: Use builders or copy() for test data.

Works as parameter/return types:

data class User(val id: String, val name: String)

@Fake  // ✅ This works
interface UserRepository {
    fun getUser(id: String): User  // ✅ Data class as return type
}

❌ Sealed Classes as @Fake Targets

Sealed hierarchies can’t be faked directly.

Workaround: Use exhaustive when-expressions or visitor patterns.

❌ Default Parameters in Interface Methods

Interfaces with default parameters are not yet supported.

Workaround: Use overloaded methods or remove defaults.

Reporting Issues

Found a limitation not listed here? Report it on GitHub.

Next Steps