How is EK9 fuzzing different from AFL or libFuzzer?

  1. Compiler fuzzing (-fuzz): stress-test the compiler itself.
  2. Mutation testing (-fuzzmutate): assess test quality.
  3. Test generation (-fuzztest): create edge-case tests.

  EK9 fuzzing: for EK9 projects, always use the built-in tools.
  AFL/libFuzzer: for C/C++ libraries or when testing binary interfaces.
  Both: complementary approaches for different layers of the stack.

defines module qa.fuzzingandmutation.fuzzvsafl

  <?-
    Demonstrates type-aware code that a byte-level fuzzer
    would struggle with but EK9 source-level fuzzing handles
    naturally. The type system ensures generated inputs are meaningful.
  -?>

  defines type

    Priority
      Low
      Normal
      High
      Critical

  defines class

    Task
      taskName as String: String()
      taskPriority as Priority: Priority()
      completed as Boolean: false

      Task()
        ->
          initialName as String
          initialPriority as Priority
        this.taskName :=? initialName
        this.taskPriority :=? initialPriority

      complete()
        this.completed: true

      isComplete() as pure
        <- done as Boolean: this.completed

      priority() as pure
        <- rtn as Priority: this.taskPriority

      operator $ as pure
        <- rtn as String: `${this.taskName} [${this.taskPriority}]`

      default operator ?

  defines function

    countByPriority() as pure
      ->
        tasks as List of Task
        targetPriority as Priority
      <- count as Integer: 0

      for task in tasks
        if task.priority() == targetPriority
          count: count + 1

  defines program

    FuzzVsAflDemo()
      stdout <- Stdout()

      tasks <- List() of Task
      tasks += Task("Write docs", Priority.Low)
      tasks += Task("Fix login", Priority.Critical)
      tasks += Task("Add tests", Priority.High)
      tasks += Task("Update deps", Priority.Normal)
      tasks += Task("Review PR", Priority.High)

      for task in tasks
        stdout.println($task)

      highCount <- countByPriority(tasks, Priority.High)
      criticalCount <- countByPriority(tasks, Priority.Critical)
      stdout.println(`High priority: ${highCount}`)
      stdout.println(`Critical: ${criticalCount}`)