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from django.test import TestCase
from pint import Context, DimensionalityError
import quantityfield.fields as fields
import quantityfield.helper as helper
from quantityfield.units import ureg
class TestMatchingUnitDimensionsHelper(TestCase):
def test_valid_choices(self):
helper.check_matching_unit_dimension(ureg, "meter", ["mile", "foot", "cm"])
def test_invalid_choices(self):
with self.assertRaises(DimensionalityError):
helper.check_matching_unit_dimension(
ureg, "meter", ["mile", "foot", "cm", "kg"]
)
class TestEdgeCases(TestCase):
def test_fix_unit_registry(self):
field = fields.IntegerQuantityField("meter")
with self.assertRaises(ValueError):
field.fix_unit_registry(1)
def test_get_prep_value(self):
field = fields.IntegerQuantityField("meter")
with self.assertRaises(ValueError):
field.get_prep_value("foobar")
class TestContextHandling(TestCase):
"""Class to test ureg.context for compatible units as described in issue #99.
pint allows users to define a special context for unit conversions,
e.g. on earth a mass can directly be converted to a force given the
acceleration 'constant' on earth.
We will test the unit compatibility via the helper function for both
both context activated globally via ureg and within a with block. Finally
test the conversion integrated inside an IntegerQuantityField. Also the
negatives are tested: without the context, mass should not be accepted
as a matching unit for force.
"""
def setUp(self):
"""Setup a pint context in the UnitRegistry."""
# Define a context where mass is equated to force via earth's
# standard acceleration of gravity and vice versa
# (https://en.wikipedia.org/wiki/Standard_gravity)
self.context = Context("earth")
# mass -> force
self.context.add_transformation(
"[mass]", "[force]", lambda ureg, x: x * ureg.gravity
)
# force -> mass
self.context.add_transformation(
"[force]", "[mass]", lambda ureg, x: x / ureg.gravity
)
ureg.add_context(self.context)
def test_context_global(self):
"""Activate ureg.context globally and test conversion compatibility directly."""
# Activate context globally and test
ureg.enable_contexts("earth")
helper.check_matching_unit_dimension(ureg, "kg", ["newton", "kN", "ton"])
ureg.disable_contexts()
def test_context_with_block(self):
"""Activate ureg.context in with block and test conversion compatibility
directly."""
# Use context with the 'with' statement
with ureg.context("earth"):
helper.check_matching_unit_dimension(ureg, "kg", ["newton", "kN", "ton"])
def test_invalid_context(self):
"""Negative test: Conversion mass to force should fail without context."""
with self.assertRaises(DimensionalityError):
helper.check_matching_unit_dimension(ureg, "kg", ["newton", "kN", "ton"])
def test_field_w_context_global(self):
"""Negative test: Conversion mass to force should fail without context."""
ureg.enable_contexts("earth")
self.field = fields.IntegerQuantityField(
base_units="kg", unit_choices=["newton", "kN", "ton"]
)
ureg.disable_contexts()
def test_field_w_context_block(self):
"""Activate ureg.context globally and test conversion compatibility complete
Field."""
with ureg.context("earth"):
self.field = fields.IntegerQuantityField(
base_units="kg", unit_choices=["newton", "kN", "ton"]
)
def test_invalid_field_wo_context(self):
"""Negative test: Conversion mass to force should fail without context."""
with self.assertRaises(DimensionalityError):
self.field = fields.IntegerQuantityField(
base_units="kg", unit_choices=["newton", "kN", "ton"]
)
def tearDown(self):
"""Disable and remove the contexts to not interfere with other tests."""
# Clean up by disabling and removing the context
ureg.disable_contexts()
ureg.remove_context("earth")
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