79 lines
2.1 KiB
Python
79 lines
2.1 KiB
Python
"""
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Tests for the order_with_respect_to Meta attribute.
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"""
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from django.db import models
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class Question(models.Model):
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text = models.CharField(max_length=200)
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class Answer(models.Model):
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text = models.CharField(max_length=200)
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question = models.ForeignKey(Question)
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class Meta:
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order_with_respect_to = 'question'
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def __unicode__(self):
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return unicode(self.text)
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__test__ = {'API_TESTS': """
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>>> q1 = Question(text="Which Beatle starts with the letter 'R'?")
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>>> q1.save()
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>>> q2 = Question(text="What is your name?")
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>>> q2.save()
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>>> Answer(text="John", question=q1).save()
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>>> Answer(text="Jonno",question=q2).save()
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>>> Answer(text="Paul", question=q1).save()
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>>> Answer(text="Paulo", question=q2).save()
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>>> Answer(text="George", question=q1).save()
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>>> Answer(text="Ringo", question=q1).save()
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The answers will always be ordered in the order they were inserted.
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>>> q1.answer_set.all()
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[<Answer: John>, <Answer: Paul>, <Answer: George>, <Answer: Ringo>]
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We can retrieve the answers related to a particular object, in the order
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they were created, once we have a particular object.
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>>> a1 = Answer.objects.filter(question=q1)[0]
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>>> a1
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<Answer: John>
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>>> a2 = a1.get_next_in_order()
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>>> a2
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<Answer: Paul>
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>>> a4 = list(Answer.objects.filter(question=q1))[-1]
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>>> a4
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<Answer: Ringo>
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>>> a4.get_previous_in_order()
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<Answer: George>
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Determining (and setting) the ordering for a particular item is also possible.
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>>> id_list = [o.pk for o in q1.answer_set.all()]
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>>> a2.question.get_answer_order() == id_list
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True
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>>> a5 = Answer(text="Number five", question=q1)
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>>> a5.save()
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It doesn't matter which answer we use to check the order, it will always be the same.
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>>> a2.question.get_answer_order() == a5.question.get_answer_order()
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True
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The ordering can be altered:
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>>> id_list = [o.pk for o in q1.answer_set.all()]
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>>> x = id_list.pop()
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>>> id_list.insert(-1, x)
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>>> a5.question.get_answer_order() == id_list
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False
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>>> a5.question.set_answer_order(id_list)
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>>> q1.answer_set.all()
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[<Answer: John>, <Answer: Paul>, <Answer: George>, <Answer: Number five>, <Answer: Ringo>]
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"""
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}
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