dimensional test of derived dimensions

[schymans]

The below should not give an error, as the dimensions of energy are compatible with mass * length ** 2 / second ** 2:

from sympy import S, exp
from sympy.physics.units import energy, length, mass, time, Quantity
u = Quantity("u")
v = Quantity("v")
u.set_dimension(energy)
v.set_dimension(mass*length**2/time**2)
Quantity._collect_factor_and_dimension(1 - (u/v))

returns
ValueError: Dimension of "-u/v" is energy*time**2/(length**2*mass), but it should be 1

[schymans]

Same problem also occurs with check_dimensions:

from sympy import S, exp
from sympy.physics.units import energy, length, mass, time, Quantity
from sympy.physics.units.systems.si import dimsys_SI, SI
from sympy.physics.units.util import convert_to, check_dimensions
u = Quantity("u")
v = Quantity("v")
SI.set_quantity_dimension(u, energy)
SI.set_quantity_dimension(v, mass*length**2/time**2)
check_dimensions(1 - (u/v))

returns
ValueError: addends have incompatible dimensions

[schymans]

And maybe a more straightforward example:

from sympy.physics.units import joule, kilogram, meter, second
from sympy.physics.units.util import check_dimensions
check_dimensions(1 - (kilogram*meter**2/second**2) / joule)

returns
ValueError: addends have incompatible dimensions