element-web/test/test-utils/utilities.ts

/*
Copyright 2024 New Vector Ltd.
Copyright 2021 The Matrix.org Foundation C.I.C.

SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only
Please see LICENSE files in the repository root for full details.
*/

import EventEmitter from "events";

import { ActionPayload } from "../../src/dispatcher/payloads";
import defaultDispatcher from "../../src/dispatcher/dispatcher";
import { DispatcherAction } from "../../src/dispatcher/actions";
import Modal from "../../src/Modal";

export const emitPromise = (e: EventEmitter, k: string | symbol) => new Promise((r) => e.once(k, r));

/**
 * Waits for a certain payload to be dispatched.
 * @param waitForAction The action string to wait for or the callback which is invoked for every dispatch. If this returns true, stops waiting.
 * @param timeout The max time to wait before giving up and stop waiting. If 0, no timeout.
 * @param dispatcher The dispatcher to listen on.
 * @returns A promise which resolves when the callback returns true. Resolves with the payload that made it stop waiting.
 * Rejects when the timeout is reached.
 */
export function untilDispatch(
    waitForAction: DispatcherAction | ((payload: ActionPayload) => boolean),
    dispatcher = defaultDispatcher,
    timeout = 1000,
): Promise<ActionPayload> {
    const callerLine = new Error().stack!.toString().split("\n")[2];
    if (typeof waitForAction === "string") {
        const action = waitForAction;
        waitForAction = (payload) => {
            return payload.action === action;
        };
    }
    const callback = waitForAction as (payload: ActionPayload) => boolean;
    return new Promise((resolve, reject) => {
        let fulfilled = false;
        let timeoutId: number;
        // set a timeout handler if needed
        if (timeout > 0) {
            timeoutId = window.setTimeout(() => {
                if (!fulfilled) {
                    reject(new Error(`untilDispatch: timed out at ${callerLine}`));
                    fulfilled = true;
                }
            }, timeout);
        }
        // listen for dispatches
        const token = dispatcher.register((p: ActionPayload) => {
            const finishWaiting = callback(p);
            if (finishWaiting || fulfilled) {
                // wait until we're told or we timeout
                // if we haven't timed out, resolve now with the payload.
                if (!fulfilled) {
                    resolve(p);
                    fulfilled = true;
                }
                // cleanup
                dispatcher.unregister(token);
                if (timeoutId) {
                    clearTimeout(timeoutId);
                }
            }
        });
    });
}

/**
 * Waits for a certain event to be emitted.
 * @param emitter The EventEmitter to listen on.
 * @param eventName The event string to wait for.
 * @param check Optional function which is invoked when the event fires. If this returns true, stops waiting.
 * @param timeout The max time to wait before giving up and stop waiting. If 0, no timeout.
 * @returns A promise which resolves when the callback returns true or when the event is emitted if
 * no callback is provided. Rejects when the timeout is reached.
 */
export function untilEmission(
    emitter: EventEmitter,
    eventName: string,
    check?: (...args: any[]) => boolean,
    timeout = 1000,
): Promise<void> {
    const callerLine = new Error().stack!.toString().split("\n")[2];
    return new Promise((resolve, reject) => {
        let fulfilled = false;
        let timeoutId: number;
        // set a timeout handler if needed
        if (timeout > 0) {
            timeoutId = window.setTimeout(() => {
                if (!fulfilled) {
                    reject(new Error(`untilEmission: timed out at ${callerLine}`));
                    fulfilled = true;
                }
            }, timeout);
        }
        const callback = (...args: any[]) => {
            // if they supplied a check function, call it now. Bail if it returns false.
            if (check) {
                if (!check(...args)) {
                    return;
                }
            }
            // we didn't time out, resolve. Otherwise, we already rejected so don't resolve now.
            if (!fulfilled) {
                resolve();
                fulfilled = true;
            }
            // cleanup
            emitter.off(eventName, callback);
            if (timeoutId) {
                clearTimeout(timeoutId);
            }
        };
        // listen for emissions
        emitter.on(eventName, callback);
    });
}

export const flushPromises = async () => await new Promise<void>((resolve) => window.setTimeout(resolve));

// with jest's modern fake timers process.nextTick is also mocked,
// flushing promises in the normal way then waits for some advancement
// of the fake timers
// https://gist.github.com/apieceofbart/e6dea8d884d29cf88cdb54ef14ddbcc4?permalink_comment_id=4018174#gistcomment-4018174
export const flushPromisesWithFakeTimers = async (): Promise<void> => {
    const promise = new Promise((resolve) => process.nextTick(resolve));
    jest.advanceTimersByTime(1);
    await promise;
};

/**
 * Call fn before calling componentDidUpdate on a react component instance, inst.
 * @param {React.Component} inst an instance of a React component.
 * @param {number} updates Number of updates to wait for. (Defaults to 1.)
 * @returns {Promise} promise that resolves when componentDidUpdate is called on
 *                    given component instance.
 */
export function waitForUpdate(inst: React.Component, updates = 1): Promise<void> {
    return new Promise<void>((resolve, reject) => {
        const cdu = inst.componentDidUpdate;

        console.log(`Waiting for ${updates} update(s)`);

        inst.componentDidUpdate = (prevProps, prevState, snapshot) => {
            updates--;
            console.log(`Got update, ${updates} remaining`);

            if (updates == 0) {
                inst.componentDidUpdate = cdu;
                resolve();
            }

            if (cdu) cdu(prevProps, prevState, snapshot);
        };
    });
}

/**
 * Advance jests fake timers and Date.now mock by ms
 * Useful for testing code using timeouts or intervals
 * that also checks timestamps
 */
export const advanceDateAndTime = (ms: number) => {
    jest.spyOn(global.Date, "now").mockReturnValue(Date.now() + ms);
    jest.advanceTimersByTime(ms);
};

/**
 * A horrible hack necessary to wait enough time to ensure any modal is shown after a
 * `Modal.createDialog(...)` call. We have to contend with the Modal code which renders
 * things asyncronhously and has weird sleeps which we should strive to remove.
 */
export const waitEnoughCyclesForModal = async ({
    useFakeTimers = false,
}: {
    useFakeTimers?: boolean;
} = {}): Promise<void> => {
    // XXX: Maybe in the future with Jest 29.5.0+, we could use `runAllTimersAsync` instead.
    const flushFunc = useFakeTimers ? flushPromisesWithFakeTimers : flushPromises;

    await flushFunc();
    await flushFunc();
    await flushFunc();
};

/**
 * A horrible hack necessary to make sure modals don't leak and pollute tests.
 * `@testing-library/react` automatic cleanup function does not pick up the async modal
 * rendering and the modals don't unmount when the component unmounts. We should strive
 * to fix this.
 */
export const clearAllModals = async (): Promise<void> => {
    // Prevent modals from leaking and polluting other tests
    let keepClosingModals = true;
    while (keepClosingModals) {
        keepClosingModals = Modal.closeCurrentModal();

        // Then wait for the screen to update (probably React rerender and async/await).
        // Important for tests using Jest fake timers to not get into an infinite loop
        // of removing the same modal because the promises don't flush otherwise.
        //
        // XXX: Maybe in the future with Jest 29.5.0+, we could use `runAllTimersAsync` instead.

        // this is called in some places where timers are not faked
        // which causes a lot of noise in the console
        // to make a hack even hackier check if timers are faked using a weird trick from github
        // then call the appropriate promise flusher
        // https://github.com/facebook/jest/issues/10555#issuecomment-1136466942
        const jestTimersFaked = setTimeout.name === "setTimeout";
        if (jestTimersFaked) {
            await flushPromisesWithFakeTimers();
        } else {
            await flushPromises();
        }
    }
};

/** Install a stub object at `navigator.mediaDevices` */
export function useMockMediaDevices(): void {
    // @ts-ignore assignment of a thing that isn't a `MediaDevices` to read-only property
    navigator["mediaDevices"] = {
        enumerateDevices: jest.fn().mockResolvedValue([]),
        getUserMedia: jest.fn(),
    };
}

/**
 * Clean up the JSDOM after each test.
 *
 * Registers `beforeEach` and `afterEach` functions which will deregister any event listeners and timers from the
 * `window` and `document` objects.
 *
 * Also clears out `localStorage` and `sessionStorage`.
 */
export function resetJsDomAfterEach(): void {
    // list of calls to run in afterEach
    const resetCalls: (() => void)[] = [];

    beforeEach(() => {
        // intercept `window.addEventListener` and `document.addEventListener`, and register 'removeEventListener' calls
        // for `afterEach`.
        for (const obj of [window, document]) {
            const originalFn = obj.addEventListener;
            obj.addEventListener = (...args: Parameters<Window["addEventListener"]>) => {
                originalFn.apply(obj, args);
                resetCalls.push(() => obj.removeEventListener(...args));
            };

            // also reset the intercept after the test
            resetCalls.push(() => {
                obj.addEventListener = originalFn;
            });
        }

        // intercept setTimeout and setInterval, and clear them at the end.
        //
        // *Don't* use jest.spyOn for this because it makes the DOM testing library think we are using fake timers.
        //
        ["setTimeout", "setInterval"].forEach((name) => {
            const originalFn = window[name as keyof Window];
            // @ts-ignore assignment to read-only property
            window[name] = (...args) => {
                const result = originalFn.apply(window, args);
                resetCalls.push(() => window.clearTimeout(result));
                return result;
            };
            resetCalls.push(() => {
                // @ts-ignore assignment to read-only property
                window[name] = originalFn;
            });
        });
    });

    afterEach(() => {
        // clean up event listeners, timers, etc.
        for (const call of resetCalls) {
            call();
        }
        resetCalls.splice(0);

        // other cleanup
        localStorage.clear();
        sessionStorage.clear();
    });
}