use std::test {}
use lib::foldable {Foldable}

def multiply (x : I64) (y : I64) : I64 := x * y

#[test]
def test_foldr_sum : Bool :=
  let res : I64 := Foldable.foldr (fn x acc => x + acc) 0 [1, 2, 3] in
  res == 6

#[test]
def test_foldr_product : Bool :=
  let res : I64 := Foldable.foldr multiply 1 [2, 3, 4] in
  res == 24

#[test]
def test_foldr_concat : Bool :=
  let res : String := Foldable.foldr (fn a acc => String.concat a acc) "" ["a", "b"] in
  res == "ab"

#[test]
def test_foldr_empty : Bool :=
  Foldable.foldr (fn x acc => x + acc) 0 [] == 0

#[test]
def test_foldr_option_some : Bool :=
  Foldable.foldr (fn x acc => x + acc) 0 (some 42) == 42

#[test]
def test_foldr_option_none : Bool :=
  Foldable.foldr (fn x acc => x + acc) 0 none == 0

#[test]
def test_foldl_sum : Bool :=
  Foldable.foldl (fn acc x => acc + x) 0 [1, 2, 3] == 6

#[test]
def test_foldl_option_some : Bool :=
  Foldable.foldl (fn acc x => acc + x) 0 (some 42) == 42

#[test]
def test_foldl_option_none : Bool :=
  Foldable.foldl (fn acc x => acc + x) 0 none == 0

#[test]
def test_foldr_foldl_equiv : Bool :=
  let fr : I64 := Foldable.foldr (fn x acc => x + acc) 0 [1, 2, 3] in
  let fl : I64 := Foldable.foldl (fn acc x => acc + x) 0 [1, 2, 3] in
  fr == fl