(module $test_module
  ;;; An enumeration
  (typename $test_errno
    (enum (@witx tag u16)
    ;;; Operation succeeded.
    $success

    ;;; A guest error occurred
    $guest_error

    ;;; Something else went wrong
    $some_other_error
    )
  )

  ;;; A boolean alias
  (typename $test_bool bool)

  ;;; A u32 alias
  (typename $test_medium_int u32)

  ;;; A u64 alias
  (typename $test_big_int u64)

  ;;; Some constants for a type
  (@witx const $test_big_int $zero 0)
  (@witx const $test_big_int $a_hundred 100)
  (@witx const $test_big_int $a_big_value 0xff00000000000000)
  (@witx const $test_big_int $a_bigger_value 0xffffffffffffffff)

  ;;; Some constants for another type, these are smaller and won't be encoded as hex
  (@witx const $test_medium_int $zero 0)
  (@witx const $test_medium_int $one 1)
  (@witx const $test_medium_int $two 2)
  (@witx const $test_medium_int $three 3)

  ;;; Flags
  (typename $test_big_flags (record (field $a bool) (field $b bool) (field $c bool) (field $d bool)))

  ;;; A structure
  (typename $test_struct (record (field $a_boolean bool) (field $a_byte u8) (field $a_string string)))

  ;;; A tuple
  (typename $test_tuple (tuple $test_bool $test_medium_int $test_big_int))

  ;;; A string
  (typename $test_string string)

  ;;; An output buffer
  (typename $test_output_buffer (out-buffer u16))

  ;;; An input buffer
  (typename $test_input_buffer (in-buffer u16))

  ;;; A tagged union
  (typename $test_tagged_union (variant (@witx tag u16) (case $first_choice u8) (case $second_choice string) (case $third_choice f32) (case $empty_choice)))

  ;;; This function returns multiple values
  (@interface func (export "a_function_that_returns_multiple_values")
    (param $some_parameter u64)
    (param $some_other_parameter string)
    (result $error (expected (tuple $test_medium_int $test_big_int) (error $test_errno)))
  )

  ;;; This function returns an actual tuple (expanded into multiple values)
  (@interface func (export "a_function_that_returns_an_actual_tuple")
    (param $some_parameter u64)
    (result $error (expected $test_tuple (error $test_errno)))
  )

  ;;; This function returns nothing
  (@interface func (export "a_function_that_returns_nothing")
    (param $some_parameter u64)
    (result $error (expected (error $test_errno)))
  )

  ;;; This function gets a string
  (@interface func (export "a_function_that_gets_a_string")
    (param $str string)
    (result $error (expected $test_bool (error $test_errno)))
  )

  ;;; This function return a tagged union
  (@interface func (export "a_function_that_returns_a_tagged_union")
    (param $str $test_string)
    (result $error (expected $test_tagged_union (error $test_errno)))
  )

  ;;; This function gets and returns a string
  (@interface func (export "a_function_that_gets_and_returns_a_string")
    (param $str $test_string)
    (result $error (expected $test_string (error $test_errno)))
  )
)