gulp-cy-tests.js

const gulp = require("gulp");
const { spawn } = require("child_process");
const cypress = require("../gulp-cypress");

// hold onto the server process
let server;

function startServer(done) {
    server = spawn(process.argv[0], ["au", "watch", "---env", "stage"], {
        detached: true,
        stdio: "ignore"
    });

    server.unref();
    done();
}

function runCypress(done) {
    const spec = "test/cypress/integration/**/*.spec.ts";
    return gulp
        .src("/")
        .pipe(cypress({spec}))
        .on("error", error => handleError(error, done))
        .on("end", () => killServer(done));
}

function killServer(done) {
    server.kill();
    done();
}

function handleError(error, done) {
    server.kill();
    done(error);
}

const runTests = gulp.series(startServer, runCypress, killServer);

module.exports = {
    run: runTests
};

gulp-cypress.js

const es = require("event-stream");
const cypress = require("cypress");

module.exports = function (options) {
    // change as required
    const defaults = {
        reporter: "mocha-teamcity-reporter",
        browser: "chrome"
    };

    options = Object.assign(defaults, options || {});

    return es.through(() => { }, function () {
        const stream = this;

        cypress.run(options)
            .then(() => {
                stream.emit("end");
            })
            .catch(() => {
                stream.emit("error");
            });
    });
};