title: Pytest data fixture causing function uses no argument 'data' error
body: <p>I have a Python Selenium testing using at pytest fixture to pass login username and password from a spreadsheet into my test. I am using openpyxl to achieve this.</p>
  
  <p>My test is as follows:</p>
  
  <pre><code>from Base import InitiateDriver
  from Pages import LogIn
  import pytest
  from DataGenerate import DataGen
  import openpyxl
  
  
  @pytest.mark.parametrize('data', DataGen.data_generator())
  def test_new():
    browser = InitiateDriver.start_browser()
    login = LogIn.LogInClass(browser)
    login.enter_username(data[0])
    login.enter_password(data[1])
  </code></pre>
  
  <p>I have a DataGen.py file to get the test data from the spreadsheet here:</p>
  
  <pre><code>import openpyxl
  
  
  def data_generator():
    wk = openpyxl.load_workbook("/users/marklane/Automation/TestData.xlsx")
    sh = wk['login']
    r = sh.max_row
    li = []
    li1 = []
    for i in range(1, r + 1):
      li1 = []
      un = sh.cell(i, 1)
      up = sh.cell(i, 2)
      li1.insert(0, un.value)
      li1.insert(1, up.value)
      li.insert(i - 1, li1)
  
      print (li)
      return li
  </code></pre>
  
  <p>when running the test I get the following error:</p>
  
  <pre><code>latform darwin -- Python 2.7.10, pytest-4.3.0, py-1.8.0, pluggy-0.8.1
  rootdir: /Users/marklane/PycharmProjects/test, inifile:
  Tests/test_TC_001_ValidateRegistration.py:None 
  (Tests/test_TC_001_ValidateRegistration.py)
  In test_new: function uses no argument 'data'
  collected 0 items / 1 errors
  
  ==================================== ERRORS ====================================
  __________ ERROR collecting Tests/test_TC_001_ValidateRegistration.py __________
  
  In test_new: function uses no argument 'data'------------------------------- Captured stdout ----------------------- ---------[[u'marklane2001', u'Ipswichtow1!']]
  !!!!!!!!!!!!!!!!!!! Interrupted: 1 errors during collection !!!!!!!!!
  </code></pre>
  
  <p>As you can see from the error, the data is being found in the spreadsheet but it is not passing that back to 'data' in my selenium lines</p>