'Regression test for https://aeon.stsci.edu/ssb/trac/pyfits/ticket/137, part 2
Ticket https://aeon.stsci.edu/ssb/trac/pyfits/ticket/137 also showed that in
float values like 0.001 the leading zero was unnecessarily being
stripped off when rewriting the header.  Though leading zeros should be
removed from integer values to prevent misinterpretation as octal by
python (for now PyFITS will still maintain the leading zeros if now
changes are made to the value, but will drop them if changes are made).'

def test_leading_zeros(self):

    c = fits.Card.fromstring('APERTURE=    +0.000000000000E+000')
    assert (str(c) == _pad('APERTURE=    +0.000000000000E+000'))
    assert (c.value == 0.0)
    c = fits.Card.fromstring('APERTURE=    0.000000000000E+000')
    assert (str(c) == _pad('APERTURE=    0.000000000000E+000'))
    assert (c.value == 0.0)
    c = fits.Card.fromstring('APERTURE=    017')
    assert (str(c) == _pad('APERTURE=    017'))
    assert (c.value == 17)
