drop.test.ts

import type { Tests } from "@vangware/test";
import type { ReadOnlyArray } from "@vangware/types";
import { drop } from "../src/drop.js";
import { iterableToArray } from "../src/iterableToArray.js";
import { asyncIterateArray } from "./utils.js";

const drop2 = drop(2);
const dropNone = drop(0);
const dropAll = drop(Infinity);

export default [
	{
		given: "an iterable of numbers and a drop 2 function",
		must: "return iterable without the first 2 elements",
		received: () => iterableToArray(drop2([0, 1, 2, 3, 4])),
		wanted: () => [2, 3, 4],
	},
	{
		given: "an iterable of numbers and a drop 0 function",
		must: "return iterable with all its elements",
		received: () => iterableToArray(dropNone([0, 1, 2, 3, 4])),
		wanted: () => [0, 1, 2, 3, 4],
	},
	{
		given: "an iterable of numbers and a drop all function",
		must: "return empty iterable",
		received: () => iterableToArray(dropAll([0, 1, 2, 3, 4])),
		wanted: () => [],
	},
	{
		given: "an async iterable of numbers and a drop 2 function",
		must: "return iterable without the first 2 elements",
		received: () =>
			iterableToArray(drop2(asyncIterateArray([0, 1, 2, 3, 4]))),
		wanted: () => [2, 3, 4],
	},
	{
		given: "an async iterable of numbers and a drop 0 function",
		must: "return iterable with all its elements",
		received: () =>
			iterableToArray(dropNone(asyncIterateArray([0, 1, 2, 3, 4]))),
		wanted: () => [0, 1, 2, 3, 4],
	},
	{
		given: "an async iterable of numbers and a drop all function",
		must: "return empty iterable",
		received: () =>
			iterableToArray(dropAll(asyncIterateArray([0, 1, 2, 3, 4]))),
		wanted: () => [],
	},
] satisfies Tests<ReadOnlyArray<number>>;