'The background color formatting attribute, L{A.bg}, emits the VT102
control sequence to set the selected background color when flattened.'

def test_background(self):

    self.assertEqual(text.assembleFormattedText(A.normal[(A.bg.red['Hello,    '], A.bg.green['world!'])]), '\x1b[41mHello,    \x1b[42mworld!')
