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|
import gleam/should
import gleam/iterator
import gleam/list
// a |> from_list |> to_list == a
pub fn to_from_list_test() {
let test = fn(subject) {
subject
|> iterator.from_list
|> iterator.to_list
|> should.equal(subject)
}
test([])
test([1])
test([1, 2])
test([1, 2, 4, 8])
}
// a |> from_list |> take(n) == a |> list.take(_, n)
pub fn take_test() {
let test = fn(n, subject) {
subject
|> iterator.from_list
|> iterator.take(n)
|> should.equal(list.take(subject, n))
}
test(0, [])
test(1, [])
test(-1, [])
test(0, [0])
test(1, [0])
test(-1, [0])
test(0, [0, 1, 2, 3, 4])
test(1, [0, 1, 2, 3, 4])
test(2, [0, 1, 2, 3, 4])
test(22, [0, 1, 2, 3, 4])
}
// a |> from_list |> fold(a, f) == a |> list.fold(_, a, f)
pub fn fold_test() {
let test = fn(subject, acc, f) {
subject
|> iterator.from_list
|> iterator.fold(acc, f)
|> should.equal(list.fold(subject, acc, f))
}
let f = fn(e, acc) { [e, ..acc] }
test([], [], f)
test([1], [], f)
test([1, 2, 3], [], f)
test([1, 2, 3, 4, 5, 6, 7, 8], [], f)
}
// a |> from_list |> map(f) |> to_list == a |> list.map(_, f)
pub fn map_test() {
let test = fn(subject, f) {
subject
|> iterator.from_list
|> iterator.map(f)
|> iterator.to_list
|> should.equal(list.map(subject, f))
}
let f = fn(e) { e * 2 }
test([], f)
test([1], f)
test([1, 2, 3], f)
test([1, 2, 3, 4, 5, 6, 7, 8], f)
}
// a |> from_list |> filter(f) |> to_list == a |> list.filter(_, f)
pub fn filter_test() {
let test = fn(subject, f) {
subject
|> iterator.from_list
|> iterator.filter(f)
|> iterator.to_list
|> should.equal(list.filter(subject, f))
}
let even = fn(x) { x % 2 == 0 }
test([], even)
test([1], even)
test([1, 2], even)
test([1, 2, 3], even)
test([1, 2, 3, 4], even)
test([1, 2, 3, 4, 5], even)
test([1, 2, 3, 4, 5, 6], even)
}
pub fn repeat_test() {
1
|> iterator.repeat
|> iterator.take(5)
|> should.equal([1, 1, 1, 1, 1])
}
pub fn cycle_test() {
[1, 2, 3]
|> iterator.from_list
|> iterator.cycle
|> iterator.take(9)
|> should.equal([1, 2, 3, 1, 2, 3, 1, 2, 3])
}
pub fn unfold_test() {
iterator.unfold(2, fn(acc) { iterator.Next(acc, acc * 2) })
|> iterator.take(5)
|> should.equal([2, 4, 8, 16, 32])
iterator.unfold(2, fn(_) { iterator.Done })
|> iterator.take(5)
|> should.equal([])
fn(n) {
case n {
0 -> iterator.Done
n -> iterator.Next(element: n, accumulator: n - 1)
}
}
|> iterator.unfold(from: 5)
|> iterator.to_list
|> should.equal([5, 4, 3, 2, 1])
}
pub fn range_test() {
let test = fn(a, b, expected) {
iterator.range(a, b)
|> iterator.to_list
|> should.equal(expected)
}
test(0, 0, [])
test(1, 1, [])
test(-1, -1, [])
test(0, 1, [0])
test(0, 5, [0, 1, 2, 3, 4])
test(1, -5, [1, 0, -1, -2, -3, -4])
}
pub fn drop_test() {
iterator.range(0, 10)
|> iterator.drop(5)
|> iterator.to_list
|> should.equal([5, 6, 7, 8, 9])
}
|
