WATIR - 无法点击链接

Question

我有一个HTML页面，如下所示：

 <div>
      <div class="drawer">
         <div class="fill-layout">
            <div class="drawer-body">
               <div class="help-resources">
                  <div>
                    <ul class="help-resources-links">
                    <li><a href="/url1"><i class="book"></i>Book</a></li>
                    <li><a href="/url2"><i class="document"></i>Document</a></li>
                    <li><a href="/url3"><i class="form"></i>Form</a></li>

我想点击

<li><a href="/url1"><i class="book"></i>Book</a></li>

并查看是否在指定的文件路径中下载了书籍

我的代码如下：

require 'watir'
prefs = {
  download: {
   prompt_for_download: true,
   default_directory: '/Users/user.name/Downloads/watir-downloads'
 }
}

browser = Watir::Browser.start 'https://admin:password@website.com'

我尝试了很少的方法，但它们都不起作用

 1. browser.div(:class, "help-resources").link(:text, "Book").click

Output :
Traceback (most recent call last):
    10: from download.rb:18:in `<main>'
     9: from /usr/local/lib/ruby/gems/2.5.0/gems/watir-6.10.3/lib/watir/elements/element.rb:125:in `click'
     8: from /usr/local/lib/ruby/gems/2.5.0/gems/watir-6.10.3/lib/watir/elements/element.rb:657:in `element_call'
     7: from /usr/local/lib/ruby/gems/2.5.0/gems/watir-6.10.3/lib/watir/elements/element.rb:661:in `rescue in element_call'
     6: from /usr/local/lib/ruby/gems/2.5.0/gems/watir-6.10.3/lib/watir/elements/element.rb:661:in `count'
     5: from /usr/local/lib/ruby/gems/2.5.0/gems/watir-6.10.3/lib/watir/element_collection.rb:29:in `each'
     4: from /usr/local/lib/ruby/gems/2.5.0/gems/watir-6.10.3/lib/watir/element_collection.rb:70:in `to_a'
     3: from /usr/local/lib/ruby/gems/2.5.0/gems/watir-6.10.3/lib/watir/element_collection.rb:124:in `elements'
     2: from /usr/local/lib/ruby/gems/2.5.0/gems/watir-6.10.3/lib/watir/elements/element.rb:603:in `ensure_context'
     1: from /usr/local/lib/ruby/gems/2.5.0/gems/watir-6.10.3/lib/watir/elements/element.rb:578:in `assert_exists'
/usr/local/lib/ruby/gems/2.5.0/gems/watir-6.10.3/lib/watir/elements/element.rb:583:in `assert_element_found': 
unable to locate element: #<Watir::Div: located: false; {:class=>"help-resources", :tag_name=>"div"}> (Watir::Exception::UnknownObjectException)

 2. browser.ul(:class, 'help-resources-links').child.a(:text, 'Book').click

Output :
assert_element_found': unable to locate element: #<Watir::UList: located: false; {:class=>"help-resources", :tag_name=>"ul"}> (Watir::Exception::UnknownObjectException)

 3. if browser.div(:class, 'help-resources').child.a(:text, 'Book').exists?
        puts "in if block"
        browser.div(:class, 'help-resources'').a(:text, 'Book').click
    end
   Doesn't print "in if block" on terminal , code executes to completion