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# encoding: utf8
import operator
from django.test import TestCase
from django.db.migrations.optimizer import MigrationOptimizer
from django.db import migrations
from django.db import models
class OptimizerTests(TestCase):
"""
Tests the migration autodetector.
"""
def optimize(self, operations):
"""
Handy shortcut for getting results + number of loops
"""
optimizer = MigrationOptimizer()
return optimizer.optimize(operations), optimizer._iterations
def assertOptimizesTo(self, operations, expected, exact=None, less_than=None):
result, iterations = self.optimize(operations)
self.assertEqual(expected, result)
if exact is not None and iterations != exact:
raise self.failureException("Optimization did not take exactly %s iterations (it took %s)" % (exact, iterations))
if less_than is not None and iterations >= less_than:
raise self.failureException("Optimization did not take less than %s iterations (it took %s)" % (less_than, iterations))
def test_operation_equality(self):
"""
Tests the equality operator on lists of operations.
If this is broken, then the optimizer will get stuck in an
infinite loop, so it's kind of important.
"""
self.assertEqual(
[migrations.DeleteModel("Test")],
[migrations.DeleteModel("Test")],
)
self.assertEqual(
[migrations.CreateModel("Test", [("name", models.CharField(max_length=255))])],
[migrations.CreateModel("Test", [("name", models.CharField(max_length=255))])],
)
self.assertNotEqual(
[migrations.CreateModel("Test", [("name", models.CharField(max_length=255))])],
[migrations.CreateModel("Test", [("name", models.CharField(max_length=100))])],
)
self.assertEqual(
[migrations.AddField("Test", "name", models.CharField(max_length=255))],
[migrations.AddField("Test", "name", models.CharField(max_length=255))],
)
self.assertNotEqual(
[migrations.AddField("Test", "name", models.CharField(max_length=255))],
[migrations.AddField("Test", "name", models.CharField(max_length=100))],
)
self.assertNotEqual(
[migrations.AddField("Test", "name", models.CharField(max_length=255))],
[migrations.AlterField("Test", "name", models.CharField(max_length=255))],
)
def test_single(self):
"""
Tests that the optimizer does nothing on a single operation,
and that it does it in just one pass.
"""
self.assertOptimizesTo(
[migrations.DeleteModel("Foo")],
[migrations.DeleteModel("Foo")],
exact = 1,
)
def test_create_delete_model(self):
"""
CreateModel and DeleteModel should collapse into nothing.
"""
self.assertOptimizesTo(
[
migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
migrations.DeleteModel("Foo"),
],
[],
)
def test_create_alter_delete_model(self):
"""
CreateModel, AlterModelTable, AlterUniqueTogether, and DeleteModel should collapse into nothing.
"""
self.assertOptimizesTo(
[
migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
migrations.AlterModelTable("Foo", "woohoo"),
migrations.AlterUniqueTogether("Foo", [["a", "b"]]),
migrations.DeleteModel("Foo"),
],
[],
)
def test_optimize_through_create(self):
"""
We should be able to optimize away create/delete through a create or delete
of a different model, but only if the create operation does not mention the model
at all.
"""
# These should work
self.assertOptimizesTo(
[
migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
migrations.CreateModel("Bar", [("size", models.IntegerField())]),
migrations.DeleteModel("Foo"),
],
[
migrations.CreateModel("Bar", [("size", models.IntegerField())]),
],
)
self.assertOptimizesTo(
[
migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
migrations.CreateModel("Bar", [("size", models.IntegerField())]),
migrations.DeleteModel("Bar"),
migrations.DeleteModel("Foo"),
],
[],
)
self.assertOptimizesTo(
[
migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
migrations.CreateModel("Bar", [("size", models.IntegerField())]),
migrations.DeleteModel("Foo"),
migrations.DeleteModel("Bar"),
],
[],
)
# This should not work - FK should block it
self.assertOptimizesTo(
[
migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
migrations.CreateModel("Bar", [("other", models.ForeignKey("testapp.Foo"))]),
migrations.DeleteModel("Foo"),
],
[
migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
migrations.CreateModel("Bar", [("other", models.ForeignKey("testapp.Foo"))]),
migrations.DeleteModel("Foo"),
],
)
# This should not work - bases should block it
self.assertOptimizesTo(
[
migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
migrations.CreateModel("Bar", [("size", models.IntegerField())], bases=("testapp.Foo", )),
migrations.DeleteModel("Foo"),
],
[
migrations.CreateModel("Foo", [("name", models.CharField(max_length=255))]),
migrations.CreateModel("Bar", [("size", models.IntegerField())], bases=("testapp.Foo", )),
migrations.DeleteModel("Foo"),
],
)
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