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453 lines
13 KiB
TypeScript
453 lines
13 KiB
TypeScript
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
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// This module is browser compatible.
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// Copyright 2019 Allain Lalonde. All rights reserved. ISC License.
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// Copyright (c) Meta Platforms, Inc. and affiliates.
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// The documentation is extracted from https://github.com/jestjs/jest/blob/main/website/versioned_docs/version-29.7/ExpectAPI.md
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// and updated for the Deno ecosystem.
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import type {
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Expected,
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ExtendMatchResult,
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Matcher,
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MatcherContext,
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MatcherKey,
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Matchers,
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} from "./_types.ts";
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import { AssertionError } from "@std/assert/assertion-error";
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import {
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addCustomEqualityTesters,
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getCustomEqualityTesters,
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} from "./_custom_equality_tester.ts";
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import { equal } from "./_equal.ts";
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import { getExtendMatchers, setExtendMatchers } from "./_extend.ts";
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import {
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toBe,
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toBeCloseTo,
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toBeDefined,
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toBeFalsy,
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toBeGreaterThan,
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toBeGreaterThanOrEqual,
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toBeInstanceOf,
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toBeLessThan,
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toBeLessThanOrEqual,
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toBeNaN,
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toBeNull,
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toBeTruthy,
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toBeUndefined,
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toContain,
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toContainEqual,
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toEqual,
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toHaveBeenCalled,
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toHaveBeenCalledTimes,
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toHaveBeenCalledWith,
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toHaveBeenLastCalledWith,
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toHaveBeenNthCalledWith,
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toHaveLastReturnedWith,
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toHaveLength,
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toHaveNthReturnedWith,
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toHaveProperty,
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toHaveReturned,
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toHaveReturnedTimes,
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toHaveReturnedWith,
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toMatch,
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toMatchObject,
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toStrictEqual,
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toThrow,
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} from "./_matchers.ts";
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import { addSerializer } from "./_snapshot_serializer.ts";
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import { isPromiseLike } from "./_utils.ts";
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import * as asymmetricMatchers from "./_asymmetric_matchers.ts";
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import type { Tester } from "./_types.ts";
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import type { SnapshotPlugin } from "./_types.ts";
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export type { AnyConstructor, Async, Expected } from "./_types.ts";
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const matchers: Record<MatcherKey, Matcher> = {
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lastCalledWith: toHaveBeenLastCalledWith,
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lastReturnedWith: toHaveLastReturnedWith,
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nthCalledWith: toHaveBeenNthCalledWith,
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nthReturnedWith: toHaveNthReturnedWith,
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toBeCalled: toHaveBeenCalled,
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toBeCalledTimes: toHaveBeenCalledTimes,
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toBeCalledWith: toHaveBeenCalledWith,
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toBeCloseTo,
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toBeDefined,
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toBeFalsy,
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toBeGreaterThanOrEqual,
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toBeGreaterThan,
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toBeInstanceOf,
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toBeLessThanOrEqual,
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toBeLessThan,
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toBeNaN,
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toBeNull,
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toBeTruthy,
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toBeUndefined,
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toBe,
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toContainEqual,
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toContain,
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toEqual,
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toHaveBeenCalledTimes,
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toHaveBeenCalledWith,
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toHaveBeenCalled,
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toHaveBeenLastCalledWith,
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toHaveBeenNthCalledWith,
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toHaveLength,
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toHaveLastReturnedWith,
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toHaveNthReturnedWith,
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toHaveProperty,
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toHaveReturnedTimes,
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toHaveReturnedWith,
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toHaveReturned,
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toMatchObject,
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toMatch,
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toReturn: toHaveReturned,
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toReturnTimes: toHaveReturnedTimes,
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toReturnWith: toHaveReturnedWith,
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toStrictEqual,
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toThrow,
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};
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/**
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* **Note:** the documentation for this module is taken from [Jest](https://github.com/jestjs/jest/blob/main/website/versioned_docs/version-29.7/ExpectAPI.md)
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* and the examples are updated for Deno.
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*
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* The `expect` function is used to test a value. You will use `expect` along with a
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* "matcher" function to assert something about a value.
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*
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* @example Usage
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* ```ts no-assert
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* import { expect } from "@std/expect";
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*
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* function bestLaCroixFlavor(): string {
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* return "grapefruit";
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* }
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*
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* Deno.test("the best flavor is grapefruit", () => {
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* expect(bestLaCroixFlavor()).toBe("grapefruit");
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* });
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* ```
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*
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* In this case, `toBe` is the matcher function. There are a lot of different
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* matcher functions, documented in the main module description.
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*
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* The argument to `expect` should be the value that your code produces, and any
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* argument to the matcher should be the correct value. If you mix them up, your
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* tests will still work, but the error messages on failing tests will look
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* strange.
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*
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* @param value - The value to perform assertions on.
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* @param customMessage - An optional custom message to include in the assertion error.
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* @returns An expected object that can be used to chain matchers.
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*
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* @module
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*/
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export function expect(value: unknown, customMessage?: string): Expected {
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let isNot = false;
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let isPromised = false;
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const self: Expected = new Proxy<Expected>(<Expected> {}, {
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get(_, name) {
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if (name === "not") {
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isNot = !isNot;
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return self;
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}
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if (name === "resolves") {
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if (!isPromiseLike(value)) {
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throw new AssertionError("expected value must be Promiselike");
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}
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isPromised = true;
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return self;
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}
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if (name === "rejects") {
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if (!isPromiseLike(value)) {
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throw new AssertionError("expected value must be a PromiseLike");
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}
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value = value.then(
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(value) => {
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throw new AssertionError(
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`Promise did not reject. resolved to ${value}`,
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);
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},
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(err) => err,
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);
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isPromised = true;
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return self;
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}
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const extendMatchers: Matchers = getExtendMatchers();
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const allMatchers = {
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...extendMatchers,
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...matchers,
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};
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const matcher = allMatchers[name as MatcherKey] as Matcher;
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if (!matcher) {
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throw new TypeError(
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typeof name === "string"
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? `matcher not found: ${name}`
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: "matcher not found",
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);
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}
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return (...args: unknown[]) => {
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function applyMatcher(value: unknown, args: unknown[]) {
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const context: MatcherContext = {
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value,
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equal,
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isNot: false,
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customMessage,
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customTesters: getCustomEqualityTesters(),
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};
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if (isNot) {
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context.isNot = true;
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}
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if (name in extendMatchers) {
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const result = matcher(context, ...args) as ExtendMatchResult;
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if (context.isNot) {
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if (result.pass) {
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throw new AssertionError(result.message());
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}
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} else if (!result.pass) {
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throw new AssertionError(result.message());
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}
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} else {
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matcher(context, ...args);
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}
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}
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return isPromised
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? (value as Promise<unknown>).then((value: unknown) =>
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applyMatcher(value, args)
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)
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: applyMatcher(value, args);
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};
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},
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});
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return self;
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}
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/**
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* You can use `expect.addEqualityTesters` to add your own methods to test if two
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* objects are equal. For example, let's say you have a class in your code that
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* represents volume and can determine if two volumes using different units are
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* equal. You may want `toEqual` (and other equality matchers) to use this custom
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* equality method when comparing to Volume classes. You can add a custom equality
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* tester to have `toEqual` detect and apply custom logic when comparing Volume
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* classes:
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*
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* @example
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* ```ts
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* import { expect } from "@std/expect";
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*
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* class Volume {
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* public amount: number;
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* public unit: "L" | "mL";
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*
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* constructor(amount: number, unit: "L" | "mL") {
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* this.amount = amount;
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* this.unit = unit;
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* }
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*
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* toString() {
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* return `[Volume ${this.amount}${this.unit}]`;
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* }
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*
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* equals(other: Volume) {
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* if (this.unit === other.unit) {
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* return this.amount === other.amount;
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* } else if (this.unit === "L" && other.unit === "mL") {
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* return this.amount * 1000 === other.amount;
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* } else {
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* return this.amount === other.amount * 1000;
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* }
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* }
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* }
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*
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* function areVolumesEqual(a: Volume, b: Volume) {
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* const isAVolume = a instanceof Volume;
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* const isBVolume = b instanceof Volume;
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* if (isAVolume && isBVolume) {
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* return a.equals(b);
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* } else if (isAVolume === isBVolume) {
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* return undefined;
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* } else {
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* return false;
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* }
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* }
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*
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* expect.addEqualityTesters([areVolumesEqual]);
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*
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* Deno.test("are equal with different units", () => {
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* expect(new Volume(1, "L")).toEqual(new Volume(1000, "mL"));
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* });
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* ```
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*/
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expect.addEqualityTesters = addCustomEqualityTesters as (
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newTesters: Tester[],
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) => void;
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/**
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* It will be removed in 0.226.0. Use `expect.addEqualityTesters` instead.
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*
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* @deprecated (will be removed in 0.226.0) Use {@linkcode expect.addSnapshotSerializer} instead.
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*/
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expect.addSnapshotSerializers = addSerializer as (
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plugin: SnapshotPlugin,
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) => void;
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/**
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* This is a no-op right now. Don't use it.
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* Todo: support serialize plugin
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*/
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expect.addSnapshotSerializer = addSerializer as (
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plugin: SnapshotPlugin,
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) => void;
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/**
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* TODO: export appropriate types to define custom matchers.
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*/
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expect.extend = setExtendMatchers as (newExtendMatchers: Matchers) => void;
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/**
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* `expect.anything()` matches anything but `null` or `undefined`. You can use it
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* inside `toEqual` or `toHaveBeenCalledWith` instead of a literal value.
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*
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* @example
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* ```js
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* import { expect, fn } from "@std/expect";
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*
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* Deno.test("map calls its argument with a non-null argument", () => {
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* const mock = jest.fn();
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* [1].map((x) => mock(x));
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* expect(mock).toHaveBeenCalledWith(expect.anything());
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* });
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```
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*/
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expect.anything = asymmetricMatchers.anything as () => ReturnType<
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typeof asymmetricMatchers.anything
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>;
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/**
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* `expect.any(constructor)` matches anything that was created with the given
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* constructor or if it's a primitive that is of the passed type. You can use it
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* inside `toEqual` or `toHaveBeenCalledWith` instead of a literal value.
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*
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* @example
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* ```ts
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* import { expect } from "@std/expect";
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*
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* class Cat {}
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* Deno.test("expect.any()", () => {
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* expect(new Cat()).toEqual(expect.any(Cat));
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* expect("Hello").toEqual(expect.any(String));
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* expect(1).toEqual(expect.any(Number));
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* expect(() => {}).toEqual(expect.any(Function));
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* expect(false).toEqual(expect.any(Boolean));
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* expect(BigInt(1)).toEqual(expect.any(BigInt));
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* expect(Symbol("sym")).toEqual(expect.any(Symbol));
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* });
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* ```
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*/
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expect.any = asymmetricMatchers.any as (
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c: unknown,
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) => ReturnType<typeof asymmetricMatchers.any>;
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/**
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* `expect.arrayContaining(array)` matches a received array which contains all of
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* the elements in the expected array. That is, the expected array is a **subset**
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* of the received array. Therefore, it matches a received array which contains
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* elements that are **not** in the expected array.
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*
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* You can use it instead of a literal value:
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*
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* - in `toEqual` or `toHaveBeenCalledWith`
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* - to match a property in `objectContaining` or `toMatchObject`
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*
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* @example
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* ```ts
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* import { expect } from "@std/expect";
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*
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* Deno.test("expect.arrayContaining() with array of numbers", () => {
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* const arr = [1, 2, 3];
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* expect([1, 2, 3, 4]).toEqual(expect.arrayContaining(arr));
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* expect([4, 5, 6]).not.toEqual(expect.arrayContaining(arr));
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* expect([1, 2, 3]).toEqual(expect.arrayContaining(arr));
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* });
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* ```
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*/
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expect.arrayContaining = asymmetricMatchers.arrayContaining as (
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// deno-lint-ignore no-explicit-any
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c: any[],
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) => ReturnType<typeof asymmetricMatchers.arrayContaining>;
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/**
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* `expect.closeTo(number, numDigits?)` is useful when comparing floating point
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* numbers in object properties or array item. If you need to compare a number,
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* please use `.toBeCloseTo` instead.
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*
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* The optional `numDigits` argument limits the number of digits to check **after**
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* the decimal point. For the default value `2`, the test criterion is
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* `Math.abs(expected - received) < 0.005 (that is, 10 ** -2 / 2)`.
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*
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* @example
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* ```ts
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* import { expect } from "@std/expect";
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*
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* Deno.test("compare float in object properties", () => {
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* expect({
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* title: "0.1 + 0.2",
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* sum: 0.1 + 0.2,
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* }).toEqual({
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* title: "0.1 + 0.2",
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* sum: expect.closeTo(0.3, 5),
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* });
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* });
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* ```
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*/
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expect.closeTo = asymmetricMatchers.closeTo as (
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num: number,
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numDigits?: number,
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) => ReturnType<typeof asymmetricMatchers.closeTo>;
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/**
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* `expect.stringContaining(string)` matches the received value if it is a string
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* that contains the exact expected string.
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*
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* @example
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* ```ts
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* import { expect } from "@std/expect";
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*
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* Deno.test("expect.stringContaining() with strings", () => {
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* expect("https://deno.com/").toEqual(expect.stringContaining("deno"));
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* expect("function").toEqual(expect.stringContaining("func"));
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*
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* expect("Hello, World").not.toEqual(expect.stringContaining("hello"));
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* expect("foobar").not.toEqual(expect.stringContaining("bazz"));
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* });
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* ```
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*/
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expect.stringContaining = asymmetricMatchers.stringContaining as (
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str: string,
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) => ReturnType<typeof asymmetricMatchers.stringContaining>;
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/**
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* `expect.stringMatching(string | regexp)` matches the received value if it is a
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* string that matches the expected string or regular expression.
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*
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* You can use it instead of a literal value:
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*
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* - in `toEqual` or `toHaveBeenCalledWith`
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* - to match an element in `arrayContaining`
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* - to match a property in `objectContaining` (not available yet) or `toMatchObject`
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*
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* @example
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* ```ts
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* import { expect } from "@std/expect";
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*
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* Deno.test("example", () => {
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* expect("deno_std").toEqual(expect.stringMatching(/std/));
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* expect("0123456789").toEqual(expect.stringMatching(/\d+/));
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* expect("e").not.toEqual(expect.stringMatching(/\s/));
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* expect("queue").not.toEqual(expect.stringMatching(/en/));
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* });
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* ```
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*/
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expect.stringMatching = asymmetricMatchers.stringMatching as (
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pattern: string | RegExp,
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) => ReturnType<typeof asymmetricMatchers.stringMatching>;
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