input: Write a function to format a given piece of text (input) with different options for font-style, size, and color. The function should return a formatted HTML string. If no options for font, size, or color are provided, the function should use "Times New Roman", '14px', and '#000000' as defaults, respectively.
  
  def format_text(text, font="Times New Roman", size='14px', color='#000000'):
      return "<span style='font-family: {}; font-size: {}; color: {};'>{}</span>".format(font, size, color, text)
  
  assert format_text('Lorem ipsum dolor sit amet, consectetur adipiscing elit.') == "<span style='font-family: Times New Roman; font-size: 14px; color: #000000;'>Lorem ipsum dolor sit amet, consectetur adipiscing elit.</span>"
  assert format_text('Test text', 'Arial', '18px', '#FF0000') == "<span style='font-family: Arial; font-size: 18px; color: #FF0000;'>Test text</span>"
  assert format_text('Sample sentence', 'Helvetica', '20px') == "<span style='font-family: Helvetica; font-size: 20px; color: #000000;'>Sample sentence</span>"
  assert format_text('Another example', color='#00FF00') == "<span style='font-family: Times New Roman; font-size: 14px; color: #00FF00;'>Another example</span>"
  assert format_text('Default settings') == "<span style='font-family: Times New Roman; font-size: 14px; color: #000000;'>Default settings</span>"
output: def format_text(text, font="Times New Roman", size='14px', color='#000000'):
      return "<span style='font-family: {}; font-size: {}; color: {};'>{}</span>".format(font, size, color, text)