text: import re
  from vispy.scene.shaders.parsing import re_identifier
  
  
  def test_identifier():
      assert(re.match('('+re_identifier+')', 'Ax2_d3__7').groups()[0]
             == 'Ax2_d3__7')
      assert(re.match('('+re_identifier+')', '_Ax2_d3__7').groups()[0]
             == '_Ax2_d3__7')
      assert(re.match(re_identifier, '7Ax2_d3__7') is None)
      assert(re.match('('+re_identifier+')', 'x,y').groups()[0] == 'x')
      assert(re.match('('+re_identifier+')', 'x y').groups()[0] == 'x')
  