v4 wdio-mocha-framework behaves incorrectly when using ".only"

Hey, I’m running into a few issues when using wdio cli to run Mocha tests:

1. When .only is appended to a describe, Webdriver seems to ignore it and incorrectly continues to run all test suites in the spec file.
2. When .only is appended to an it test case, it correctly becomes the only test case to run, but suffers from a different problem: it runs asynchronously instead of synchronously.

For example, the code below has two identical tests, but one is sync and the other is async. When the suite is run, Test 1 passes and Test 2 fails. When Test 1 is appended with .only, it fails. When Test 2 is appended with .only, it passes.

describe('sanity tests', function () {
    it('Test 1: sync google search', function (done) {
        browser.url('https://www.google.com');
        browser.setValue('input[type="text"]', 'test search string');
        browser.click('button[type="submit"]');
        browser.pause(1000);
        assert.equal(browser.getTitle(), 'test search string - Google Search', "Search title is incorrect");
    });

    it('Test 2: async google search', function (done) {
        browser.url('https://www.google.com')
            .setValue('input[type="text"]', 'test search string')
            .click('button[type="submit"]')
            .pause(1000)
            .getTitle(function(err, title) {
                assert.equal(browser.title, 'test search string - Google Search', "Search title is incorrect");
            })
            .call(done);
    });
});

Node modules being used:

    "mocha": "2.4.5",
    "selenium-standalone": "4.9.0",
    "wdio-mocha-framework": "0.2.11",
    "webdriverio": "4.0.3"

[christian-bromann]

Just fyi: describe.only won’t work because each spec file runs in its own child process and doesn’t know about other files. We will introduce a global grep/fgrep option with #1247

[albertogasparin]

FYI, I’ve implemented a “quick and dirty” solution to support it (I prefer a slower bootstrap than having my entire suite running because I forgot .only is not working as it should):

// wdio.conf.js
function getTestFiles(filesPattern) {
  let glob = require('glob');
  let fs = require('fs');
  let files = glob.sync(filesPattern, { cache: true });
  let singleSpec;
  files.some((f) => fs.readFileSync(f).indexOf('describe.only') >= 0 && (singleSpec = f));
  return singleSpec || filesPattern;
}

let config = {
  specs: [
    getTestFiles('./tests/**/*.spec.js'),
  ],
  //...
};