Files
pear/tests/core/iterable.test.ts
2024-07-20 15:30:48 -05:00

89 lines
2.1 KiB
TypeScript

import {
fill, range, limit
} from "../../core/iterable.ts"
import { assertEquals, assert } from "https://deno.land/[email protected]/testing/asserts.ts"
Deno.test("fill, yield the same value every time", () => {
const count = 50_000
const item = "hi"
let i = 0
for (const el of fill(item, count)) {
assertEquals(el, item)
i++
}
assertEquals(i, count)
})
Deno.test("range: one arg", () => {
const iter = range(50_000)
for (let i = 0; i < 50_000; i++) {
const next = iter.next()
assertEquals(next.value, i)
}
assert(iter.next().done)
})
Deno.test("range: two args, positive", () => {
const iter = range(40, 50)
for (let i = 40; i < 50; i++) {
const next = iter.next()
assertEquals(next.value, i)
}
assert(iter.next().done)
})
Deno.test("range: two args, negative", () => {
const iter = range(50, 40)
for (let i = 50; i > 40; i--) {
const next = iter.next()
assertEquals(next.value, i)
}
assert(iter.next().done)
})
Deno.test("range: three args, positive", () => {
const iter = range(60, 80, 4)
for (let i = 60; i < 80; i += 4) {
const next = iter.next()
assertEquals(next.value, i)
}
assert(iter.next().done)
})
Deno.test("range: three args, negative", () => {
const iter = range(80, 60, 4)
for (let i = 80; i > 60; i -= 4) {
const next = iter.next()
assertEquals(next.value, i)
}
assert(iter.next().done)
})
Deno.test("limit: limits to the first n elements", () => {
const values: number[] = []
const truth = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181]
const count = truth.length
for (const value of limit(count, fibonacci())) {
values.push(value)
}
assertEquals(values.length, count)
truth.forEach((val, i) => {
assertEquals(values[i], val)
})
})
function* fibonacci() {
let back2 = 0
let back1 = 1
yield back2
yield back1
while (true) {
const sum = back2 + back1
back2 = back1
back1 = sum
yield sum
}
}