def test_cgs_equivalent():
"""
Get cgs equivalent to some unit.
"""
from dimensionful.dimensions import mass_density
from dimensionful.units import get_conversion_factor
Msun_cgs = 1.98892e33
Mpc_cgs = 3.08568e24
u1 = Unit("Msun * Mpc**-3")
u2 = Unit("g * cm**-3")
u3 = u1.get_cgs_equivalent()
assert u2.expr == u3.expr
assert u2 == u3
assert equal_sigfigs(u1.cgs_value, Msun_cgs / Mpc_cgs ** 3, 8)
assert u2.cgs_value == 1
assert u3.cgs_value == 1
assert u1.dimensions == mass_density
assert u2.dimensions == mass_density
assert u3.dimensions == mass_density
assert equal_sigfigs(get_conversion_factor(u1, u3), Msun_cgs / Mpc_cgs ** 3, 8)
def test_get_in_cgs():
"""
Get cosmological density quantity in cgs.
"""
u1 = Unit("Msun * Mpc**-3")
u2 = Unit("g * cm**-3")
q1 = Quantity(1.47721e11, u1)
q2 = q1.get_in_cgs()
assert equal_sigfigs(q2.data, 1e-29, required_precision)
assert q2.units == u2
def test_convert_to_cgs():
"""
Convert a cosmological density quantity to cgs.
"""
u1 = Unit("Msun * Mpc**-3")
u2 = Unit("g * cm**-3")
q1 = Quantity(1.47721e11, "Msun * Mpc**-3")
assert q1.units == u1
q1.convert_to_cgs()
assert equal_sigfigs(q1.data, 1e-29, required_precision)
assert q1.units == u2
def test_convert_to():
"""
Convert a density quantity from cgs to cosmological units.
"""
u1 = Unit("g * cm**-3")
u2 = Unit("Msun * Mpc**-3")
q1 = Quantity(1e-29, u1)
assert q1.units == u1
q1.convert_to(u2)
assert equal_sigfigs(q1.data, 1.47721e11, required_precision)
assert q1.units == u2
