Add expect.arrayContaining()

expect/_array_containing_test.ts

@@ -0,0 +1,14 @@
+import { expect } from "./expect.ts";
+
+Deno.test("expect.arrayContaining() with array of numbers", () => {
+  const arr = [1, 2, 3];
+  expect([1, 2, 3, 4]).toEqual(expect.arrayContaining(arr));
+  expect([4, 5, 6]).not.toEqual(expect.arrayContaining(arr));
+  expect([1, 2, 3]).toEqual(expect.arrayContaining(arr));
+});
+
+Deno.test("expect.arrayContaining() with array of mixed types", () => {
+  const arr = [1, 2, "hello"];
+  expect([1, 2, 3, "hello", "bye"]).toEqual(expect.arrayContaining(arr));
+  expect([4, "bye"]).not.toEqual(expect.arrayContaining(arr));
+});

expect/_asymmetric_matchers.ts

@@ -1,3 +1,6 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+// deno-lint-ignore-file no-explicit-any
+
 abstract class AsymmetricMatcher<T> {
   constructor(
     protected value: T,
@@ -61,3 +64,16 @@ export class Any extends AsymmetricMatcher<any> {
 export function any(c: unknown): Any {
   return new Any(c);
 }
+
+export class ArrayContaining extends AsymmetricMatcher<any[]> {
+  constructor(arr: any[]) {
+    super(arr);
+  }
+  equals(other: any[]): boolean {
+    return this.value.every((e) => other.includes(e));
+  }
+}
+
+export function arrayContaining(c: any[]): ArrayContaining {
+  return new ArrayContaining(c);
+}

expect/_equal.ts

@@ -3,7 +3,7 @@
 // This file is copied from `std/assert`.
 
 import { EqualOptions } from "./_types.ts";
-import { Any, Anything } from "./_asymmetric_matchers.ts";
+import { Any, Anything, ArrayContaining } from "./_asymmetric_matchers.ts";
 
 function isKeyedCollection(x: unknown): x is Set<unknown> {
   return [Symbol.iterator, "size"].every((k) => k in (x as Set<unknown>));
@@ -59,6 +59,9 @@ export function equal(c: unknown, d: unknown, options?: EqualOptions): boolean {
     if (b instanceof Any) {
       return b.equals(a);
     }
+    if (b instanceof ArrayContaining && a instanceof Array) {
+      return b.equals(a);
+    }
     if (a instanceof Date && b instanceof Date) {
       const aTime = a.getTime();
       const bTime = b.getTime();

expect/expect.ts

@@ -47,7 +47,7 @@ import {
   toThrow,
 } from "./_matchers.ts";
 import { isPromiseLike } from "./_utils.ts";
-import { any, anything } from "./_asymmetric_matchers.ts";
+import { any, anything, arrayContaining } from "./_asymmetric_matchers.ts";
 
 const matchers: Record<MatcherKey, Matcher> = {
   lastCalledWith: toHaveBeenLastCalledWith,
@@ -171,3 +171,4 @@ export function expect(value: unknown, customMessage?: string): Expected {
 expect.addEqualityTesters = addCustomEqualityTesters;
 expect.anything = anything;
 expect.any = any;
+expect.arrayContaining = arrayContaining;