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| from sympy.physics.units import DimensionSystem, joule, second, ampere | |
| from sympy.core.numbers import Rational | |
| from sympy.core.singleton import S | |
| from sympy.physics.units.definitions import c, kg, m, s | |
| from sympy.physics.units.definitions.dimension_definitions import length, time | |
| from sympy.physics.units.quantities import Quantity | |
| from sympy.physics.units.unitsystem import UnitSystem | |
| from sympy.physics.units.util import convert_to | |
| def test_definition(): | |
| # want to test if the system can have several units of the same dimension | |
| dm = Quantity("dm") | |
| base = (m, s) | |
| # base_dim = (m.dimension, s.dimension) | |
| ms = UnitSystem(base, (c, dm), "MS", "MS system") | |
| ms.set_quantity_dimension(dm, length) | |
| ms.set_quantity_scale_factor(dm, Rational(1, 10)) | |
| assert set(ms._base_units) == set(base) | |
| assert set(ms._units) == {m, s, c, dm} | |
| # assert ms._units == DimensionSystem._sort_dims(base + (velocity,)) | |
| assert ms.name == "MS" | |
| assert ms.descr == "MS system" | |
| def test_str_repr(): | |
| assert str(UnitSystem((m, s), name="MS")) == "MS" | |
| assert str(UnitSystem((m, s))) == "UnitSystem((meter, second))" | |
| assert repr(UnitSystem((m, s))) == "<UnitSystem: (%s, %s)>" % (m, s) | |
| def test_convert_to(): | |
| A = Quantity("A") | |
| A.set_global_relative_scale_factor(S.One, ampere) | |
| Js = Quantity("Js") | |
| Js.set_global_relative_scale_factor(S.One, joule*second) | |
| mksa = UnitSystem((m, kg, s, A), (Js,)) | |
| assert convert_to(Js, mksa._base_units) == m**2*kg*s**-1/1000 | |
| def test_extend(): | |
| ms = UnitSystem((m, s), (c,)) | |
| Js = Quantity("Js") | |
| Js.set_global_relative_scale_factor(1, joule*second) | |
| 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_dim(): | |
| dimsys = UnitSystem((m, kg, s), (c,)) | |
| assert dimsys.dim == 3 | |
| def test_is_consistent(): | |
| dimension_system = DimensionSystem([length, time]) | |
| us = UnitSystem([m, s], dimension_system=dimension_system) | |
| assert us.is_consistent == True | |
| def test_get_units_non_prefixed(): | |
| from sympy.physics.units import volt, ohm | |
| unit_system = UnitSystem.get_unit_system("SI") | |
| units = unit_system.get_units_non_prefixed() | |
| for prefix in ["giga", "tera", "peta", "exa", "zetta", "yotta", "kilo", "hecto", "deca", "deci", "centi", "milli", "micro", "nano", "pico", "femto", "atto", "zepto", "yocto"]: | |
| for unit in units: | |
| assert isinstance(unit, Quantity), f"{unit} must be a Quantity, not {type(unit)}" | |
| assert not unit.is_prefixed, f"{unit} is marked as prefixed" | |
| assert not unit.is_physical_constant, f"{unit} is marked as physics constant" | |
| assert not unit.name.name.startswith(prefix), f"Unit {unit.name} has prefix {prefix}" | |
| assert volt in units | |
| assert ohm in units | |
| def test_derived_units_must_exist_in_unit_system(): | |
| for unit_system in UnitSystem._unit_systems.values(): | |
| for preferred_unit in unit_system.derived_units.values(): | |
| units = preferred_unit.atoms(Quantity) | |
| for unit in units: | |
| assert unit in unit_system._units, f"Unit {unit} is not in unit system {unit_system}" | |