describe('changeLanguage', () => {
      it('it should keep changeLanguage call in order', () => {
        const instance = i18next.createInstance();
        const makeLang = (lan, delay) => ({
          delay,
          value: {
            foo: `${lan}`,
          },
        });
        const langMap = {
          en: makeLang('en', 100),
          zh: makeLang('zh', 500),
          es: makeLang('es', 300),
          jp: makeLang('jp', 200),
        };

        return new Promise(resolve => {
          instance
            .use({
              type: 'backend',
              read: function(language, namespace, callback) {
                const lang = langMap[language];

                setTimeout(() => {
                  callback(null, lang.value);
                }, lang.delay);
              },
            })
            .init(
              {
                fallbackLng: 'en',
              },
              (err, t) => {
                resolve(
                  Promise.all([
                    instance.changeLanguage('en'),
                    instance.changeLanguage('zh'),
                    instance.changeLanguage('jp'),
                    instance.changeLanguage('es'),
                  ]).then(() => {
                    expect(t('foo')).to.equal('es');
                  }),
                );
              },
            );
        });
      });
    });