def test_extend():
ms = UnitSystem((m, s), (c,))
Js = Unit(action)
mks = ms.extend((kg,), (Js,))
res = UnitSystem((m, s, kg), (c, Js))
assert set(mks._base_units) == set(res._base_units)
assert set(mks._units) == set(res._units)
def test_call():
A = Unit(current)
Js = Unit(action)
mksa = UnitSystem((m, kg, s, A), (Js,))
assert mksa(Js) == mksa.print_unit_base(Js)
assert mksa(Js.dim) == mksa._system(Js.dim)
q = Quantity(10, Js)
assert mksa(q) == "%g %s" % (q.factor, mksa(Js))
def test_get_unit():
ms = UnitSystem((m, s), (c,))
assert ms.get_unit("s") == s
assert ms.get_unit(s) == s
assert ms.get_unit(Unit(time)) == s
assert ms["s"] == ms.get_unit("s")
raises(KeyError, lambda: ms["g"])
def test_definition():
# want to test if the system can have several units of the same dimension
dm = Unit(m, factor=0.1)
base = (m, s)
base_dim = (m.dim, s.dim)
ms = UnitSystem(base, (c, dm), "MS", "MS system")
assert set(ms._base_units) == set(base)
assert set(ms._units) == set((m, s, c, dm))
#assert ms._units == DimensionSystem._sort_dims(base + (velocity,))
assert ms.name == "MS"
assert ms.descr == "MS system"
assert ms._system._base_dims == DimensionSystem.sort_dims(base_dim)
assert set(ms._system._dims) == set(base_dim + (velocity,))
action = Dimension(name="action", symbol="A", length=2, mass=1, time=-1)
energy = Dimension(name="energy", symbol="E", length=2, mass=1, time=-2)
velocity = Dimension(name="velocity", symbol="V", length=1, time=-1)
# derived dimensions
length = Dimension(name="length", symbol="L", length=1)
mass = Dimension(name="mass", symbol="M", mass=1)
time = Dimension(name="time", symbol="T", time=1)
acceleration = Dimension(name="acceleration", length=1, time=-2)
momentum = Dimension(name="momentum", mass=1, length=1, time=-1)
force = Dimension(name="force", symbol="F", mass=1, length=1, time=-2)
power = Dimension(name="power", length=2, mass=1, time=-3)
frequency = Dimension(name="frequency", symbol="f", time=-1)
dims = (length, mass, time, momentum, force, energy, power, frequency)
# dimension system
natural_dim = DimensionSystem(base=(action, energy, velocity),
dims=dims,
name="Natural system")
# base units
hbar = Constant(action, factor=1.05457266e-34, abbrev="hbar")
eV = Unit(energy, factor=1.60219e-19, abbrev="eV")
c = Constant(velocity, factor=299792458, abbrev="c")
units = prefix_unit(eV, PREFIXES)
# unit system
natural = UnitSystem(base=(hbar, eV, c), units=units, name="Natural system")
def test_is_consistent():
assert UnitSystem((m, s)).is_consistent is True
def test_dim():
dimsys = UnitSystem((m, kg, s), (c,))
assert dimsys.dim == 3
def test_print_unit_base():
A = Unit(current)
Js = Unit(action)
mksa = UnitSystem((m, kg, s, A), (Js,))
assert mksa.print_unit_base(Js) == "0.001 m^2 kg s^-2"
def test_str_repr():
assert str(UnitSystem((m, s), name="MS")) == "MS"
assert str(UnitSystem((m, s))) == "(m, s)"
assert (repr(UnitSystem((m, s))) == "<UnitSystem: (%s, %s)>"
% (m.abbrev_dim, s.abbrev_dim))
def test_error_definition():
raises(ValueError, lambda: UnitSystem((m, s, c)))