def test_geo_float_rounding(self):
"""
By default, the :py:module:`decimal` module uses the 'round-half-even'
algorithm for rounding numbers.
Since the rounding method can be set in a global context for the
:py:module:`decimal` module, we want to make sure the
:py:function:`openquake.shapes.geo_float` is unaffected context
changes.
"""
decimal.getcontext().rounding = decimal.ROUND_FLOOR
# changing the decimal context rounding should not affect the behavior
# of geo_float
self.assertEqual(-121.0000001, shapes.geo_float(-121.00000009))
# reset the global context so we don't potentially screw up other tests
decimal.getcontext().rounding = decimal.ROUND_HALF_EVEN
def test_geo_float(self):
"""
This test exercises the :py:function:`openquake.shapes.geo_float`
function.
Basically, the function should take any float number and round it to a
fixed number of decimal places (for example, 7 places). The rounding
method used is the default for the :py:module:`decimal` module, which
is ROUND_HALF_EVEN.
For more information on 'half-even' rounding, there is a good
explanation here:
http://www.diycalculator.com/popup-m-round.shtml#A5
"""
in_values = (29.000000000000004, -121.00000009, -121.00000001, 121.00000005, 121.00000006)
out_values = (29.0, -121.0000001, -121.0, 121.0, 121.0000001)
for i, val in enumerate(in_values):
self.assertEqual(out_values[i], shapes.geo_float(in_values[i]))
