function expectInput(browser, expected) {
    browser.execute(expected => {
        return window.app.manager.input.inputEditorView.state.doc.toString();
    }, [expected], function({value}) {
        if (expected instanceof RegExp) {
            browser.expect(value).match(expected);
        } else {
            browser.expect(value).to.be.equal(expected);
        }
    });
}
@function
Tests whether the input matches a given value

@param {Browser} browser - Nightwatch client
@param {string|RegExp} expected - The expected input value