Unable to find field "username" that is not disabled (Capybara::ElementNotFound) - ruby

Question

I'm trying to test a simple login form using cucumber / rspec / capybara. But I'm having trouble detecting elements on the page and doing any sort of test.
Unable to find field "username" that is not disabled (Capybara::ElementNotFound)
Feature File
Feature: Login
Scenario: correct login credentials
Given I am on the admin_login page
When I fill in "username" with "thomas"
ENV
require 'capybara'
require 'rspec'
require 'capybara/cucumber'
require 'rack'
require_relative '../../config'
ENV['RACK_ENV'] = 'test'
Capybara.ignore_hidden_elements = false
Capybara.app = Sinatra::Application
class Sinatra::ApplicationWorld
include RSpec::Expectations
include RSpec::Matchers
include Capybara::DSL
end
World do
Sinatra::ApplicationWorld.new
end
WEB STEP
When /^(?:|I )fill in "([^\"]*)" with "([^\"]*)"(?: within "([^\"]*)")?$/ do |field, value, selector|
with_scope(selector) do
fill_in(field,visible: false, :with => value)
end
end
HTML
<div class="container">
<div class="row">
<div class="col-md-4 col-md-offset-4">
<div class="login-panel panel panel-default">
<div class="panel-heading">
<h3 class="panel-title">Please Sign In To Pied Piper</h3>
</div>
<div class="panel-body">
<form role="form" action="/admin/login" method="post" label="form">
<fieldset label ="form" >
<div class="form-group">
<input label="username" class="form-control" placeholder="username" name="username" id="username" type="text" value="<%= params[:username] %>" autofocus>
</div>
<div class="form-group">
<input class="form-control" placeholder="Password" name="password" type="password" value="<%= params[:password]%>">
</div>
<div class="checkbox">
<label>
<input name="remember" type="checkbox" value="Remember Me">Remember Me
</label>
</div>
<button type="submit"><a class="btn btn-lg btn-success btn-block">Login</a></button>
<button>Return to Main Site</button>
</fieldset>
</form>
</div>
</div>
</div>
</div>
</div>

Answer 1

I got the same problem with my rails appliction and the way I solved it was by giving an id to that field
<%= f.text_field :name, class: 'form-control',id:"name" %>