122 lines
4.1 KiB
Python
122 lines
4.1 KiB
Python
from unittest import TestCase
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from django.template import Context, Engine
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class CallableVariablesTests(TestCase):
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@classmethod
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def setUpClass(cls):
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cls.engine = Engine()
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super().setUpClass()
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def test_callable(self):
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class Doodad:
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def __init__(self, value):
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self.num_calls = 0
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self.value = value
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def __call__(self):
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self.num_calls += 1
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return {"the_value": self.value}
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my_doodad = Doodad(42)
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c = Context({"my_doodad": my_doodad})
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# We can't access ``my_doodad.value`` in the template, because
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# ``my_doodad.__call__`` will be invoked first, yielding a dictionary
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# without a key ``value``.
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t = self.engine.from_string("{{ my_doodad.value }}")
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self.assertEqual(t.render(c), "")
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# We can confirm that the doodad has been called
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self.assertEqual(my_doodad.num_calls, 1)
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# But we can access keys on the dict that's returned
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# by ``__call__``, instead.
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t = self.engine.from_string("{{ my_doodad.the_value }}")
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self.assertEqual(t.render(c), "42")
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self.assertEqual(my_doodad.num_calls, 2)
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def test_alters_data(self):
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class Doodad:
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alters_data = True
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def __init__(self, value):
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self.num_calls = 0
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self.value = value
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def __call__(self):
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self.num_calls += 1
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return {"the_value": self.value}
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my_doodad = Doodad(42)
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c = Context({"my_doodad": my_doodad})
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# Since ``my_doodad.alters_data`` is True, the template system will not
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# try to call our doodad but will use string_if_invalid
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t = self.engine.from_string("{{ my_doodad.value }}")
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self.assertEqual(t.render(c), "")
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t = self.engine.from_string("{{ my_doodad.the_value }}")
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self.assertEqual(t.render(c), "")
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# Double-check that the object was really never called during the
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# template rendering.
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self.assertEqual(my_doodad.num_calls, 0)
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def test_do_not_call(self):
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class Doodad:
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do_not_call_in_templates = True
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def __init__(self, value):
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self.num_calls = 0
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self.value = value
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def __call__(self):
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self.num_calls += 1
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return {"the_value": self.value}
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my_doodad = Doodad(42)
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c = Context({"my_doodad": my_doodad})
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# Since ``my_doodad.do_not_call_in_templates`` is True, the template
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# system will not try to call our doodad. We can access its attributes
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# as normal, and we don't have access to the dict that it returns when
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# called.
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t = self.engine.from_string("{{ my_doodad.value }}")
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self.assertEqual(t.render(c), "42")
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t = self.engine.from_string("{{ my_doodad.the_value }}")
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self.assertEqual(t.render(c), "")
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# Double-check that the object was really never called during the
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# template rendering.
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self.assertEqual(my_doodad.num_calls, 0)
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def test_do_not_call_and_alters_data(self):
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# If we combine ``alters_data`` and ``do_not_call_in_templates``, the
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# ``alters_data`` attribute will not make any difference in the
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# template system's behavior.
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class Doodad:
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do_not_call_in_templates = True
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alters_data = True
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def __init__(self, value):
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self.num_calls = 0
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self.value = value
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def __call__(self):
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self.num_calls += 1
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return {"the_value": self.value}
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my_doodad = Doodad(42)
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c = Context({"my_doodad": my_doodad})
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t = self.engine.from_string("{{ my_doodad.value }}")
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self.assertEqual(t.render(c), "42")
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t = self.engine.from_string("{{ my_doodad.the_value }}")
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self.assertEqual(t.render(c), "")
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# Double-check that the object was really never called during the
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# template rendering.
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self.assertEqual(my_doodad.num_calls, 0)
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