def test_twa_90_degrees_heel():
r""" Boat at 90° heel."""
with pytest.raises(ValueError):
true_wind_angle(apparent_wind_speed=10.,
apparent_wind_angle=75.,
boatspeed=3.,
heel_angle=90.)
def test_twa_opposite_heel_angles():
r"""Opposite heel angles should result in the same true wind angle"""
twa_heeled_40_degrees = true_wind_angle(apparent_wind_speed=10.,
apparent_wind_angle=120.,
boatspeed=3.,
heel_angle=40.)
twa_counterheeled_40_degrees = true_wind_angle(apparent_wind_speed=10.,
apparent_wind_angle=120.,
boatspeed=3.,
heel_angle=-40.)
assert twa_heeled_40_degrees == twa_counterheeled_40_degrees
def test_twa_known_values_going_backwards():
r"""Known values going backwards."""
twa_backwards_reaching_same_speed_as_tws = \
true_wind_angle(apparent_wind_speed=10. * math.sqrt(2.),
apparent_wind_angle=135.,
boatspeed=-10.)
expected_value, atol = 90., 1e-6
assert expected_value - atol <= twa_backwards_reaching_same_speed_as_tws <= expected_value + atol
# Head to wind, going backwards at the same speed as true_wind_speed
twa_head_to_wind_no_true = true_wind_angle(apparent_wind_speed=0.,
apparent_wind_angle=0.,
boatspeed=-10.)
expected_value, atol = 0., 1e-6
assert expected_value - atol <= twa_head_to_wind_no_true <= expected_value + atol
def test_twa_known_values():
r"""Known values."""
twa_reaching_same_speed_as_tws = \
true_wind_angle(apparent_wind_speed=10. * math.sqrt(2.),
apparent_wind_angle=45.,
boatspeed=10.)
expected_value, atol = 90., 1e-6
assert expected_value - atol <= twa_reaching_same_speed_as_tws <= expected_value + atol
def test_twa_zero_boatspeed_awa():
r"""At zero speed, the true wind angle
and the apparent wind angle should be equal"""
twa_zero_boatspeed_1 = true_wind_angle(apparent_wind_speed=10.,
apparent_wind_angle=45.,
boatspeed=0.)
assert twa_zero_boatspeed_1 == 45.
twa_zero_boatspeed_2 = true_wind_angle(apparent_wind_speed=10.,
apparent_wind_angle=-165.,
boatspeed=0.)
expected_value, atol = -165., 1e-6
assert expected_value - atol <= twa_zero_boatspeed_2 <= expected_value + atol
twa_zero_boatspeed_3 = true_wind_angle(apparent_wind_speed=10.,
apparent_wind_angle=90.,
boatspeed=0.)
assert twa_zero_boatspeed_3 == 90.
def test_twa_awa_gt_180():
r"""Apparent wind angle higher than 180, should raise a ValueError"""
with pytest.raises(ValueError):
true_wind_angle(apparent_wind_speed=1.,
apparent_wind_angle=181.,
boatspeed=0.)
def test_twa_awa_lt_minus180():
r"""Apparent wind angle lower than -180, should raise a ValueError"""
with pytest.raises(ValueError):
true_wind_angle(apparent_wind_speed=1.,
apparent_wind_angle=-181.,
boatspeed=0.)
def test_twa_negative_aws():
r"""Negative apparent wind speed, should raise a ValueError"""
with pytest.raises(ValueError):
true_wind_angle(apparent_wind_speed=-1.,
apparent_wind_angle=45.,
boatspeed=0.)