How do I generate test cases with -fuzztest in EK9?

  ek9 -fuzztest source.ek9 output.ek9

  Functions: parameter types, return types, and purity.
  Classes: constructors, operators, and public methods.
  Records: constructors and operators.
  Enumerations: values and constrained ranges.

  Integer: 0, 1, -1, MAX, MIN, boundary values.
  Float: 0.0, -0.0, very small, very large, boundary values.
  String: empty, single char, very long, special characters.
  Boolean: true, false.
  Collections: empty, single item, many items.

  -n 200          Generate at most 200 candidates (default 200).
  -seed 42        Reproducible test generation.
  -overwrite      Replace existing output file.

defines module qa.fuzzingandmutation.generatetests

  <?-
    Source code that would be analysed by -fuzztest.
    The generator would harvest these functions and create
    @Test programs exercising edge-case inputs.
  -?>

  defines function

    <?-
      Test generator would try: 0, 1, -1, MAX, MIN.
      Edge case: negative numbers should return false.
    -?>
    isPrime()
      -> candidate as Integer
      <- prime as Boolean: false

      two <- 2
      if candidate >= two
        divisor <- two
        foundDivisor <- false
        while divisor * divisor <= candidate and not foundDivisor
          zero <- 0
          if candidate mod divisor == zero
            foundDivisor: true
          divisor: divisor + 1
        prime: not foundDivisor

    <?-
      Test generator would try: empty string, single char,
      already uppercase, mixed case.
    -?>
    isAllUpperCase()
      -> text as String
      <- allUpper as Boolean: false

      if text?
        upper <- text.upperCase()
        allUpper: text == upper

  defines program

    GenerateTestsDemo()
      stdout <- Stdout()

      for candidate in [1, 2, 3, 4, 5, 17, 20, 97]
        stdout.println(`${candidate} prime: ${isPrime(candidate)}`)

      for word in ["HELLO", "Hello", "world", "EK9"]
        stdout.println(`${word} all upper: ${isAllUpperCase(word)}`)