django/tests/migrations/test_writer.py

# encoding: utf8
from __future__ import unicode_literals

import datetime
import os
import tokenize

from django.core.validators import RegexValidator, EmailValidator
from django.db import models, migrations
from django.db.migrations.writer import MigrationWriter, SettingsReference
from django.test import TestCase
from django.conf import settings
from django.utils import datetime_safe, six
from django.utils.deconstruct import deconstructible
from django.utils.translation import ugettext_lazy as _
from django.utils.timezone import get_default_timezone


class WriterTests(TestCase):
    """
    Tests the migration writer (makes migration files from Migration instances)
    """

    def safe_exec(self, string, value=None):
        l = {}
        try:
            exec(string, globals(), l)
        except Exception as e:
            if value:
                self.fail("Could not exec %r (from value %r): %s" % (string.strip(), value, e))
            else:
                self.fail("Could not exec %r: %s" % (string.strip(), e))
        return l

    def serialize_round_trip(self, value):
        string, imports = MigrationWriter.serialize(value)
        return self.safe_exec("%s\ntest_value_result = %s" % ("\n".join(imports), string), value)['test_value_result']

    def assertSerializedEqual(self, value):
        self.assertEqual(self.serialize_round_trip(value), value)

    def assertSerializedResultEqual(self, value, target):
        self.assertEqual(MigrationWriter.serialize(value), target)

    def assertSerializedFieldEqual(self, value):
        new_value = self.serialize_round_trip(value)
        self.assertEqual(value.__class__, new_value.__class__)
        self.assertEqual(value.max_length, new_value.max_length)
        self.assertEqual(value.null, new_value.null)
        self.assertEqual(value.unique, new_value.unique)

    def test_serialize(self):
        """
        Tests various different forms of the serializer.
        This does not care about formatting, just that the parsed result is
        correct, so we always exec() the result and check that.
        """
        # Basic values
        self.assertSerializedEqual(1)
        self.assertSerializedEqual(None)
        self.assertSerializedEqual(b"foobar")
        string, imports = MigrationWriter.serialize(b"foobar")
        self.assertEqual(string, "b'foobar'")
        self.assertSerializedEqual("föobár")
        string, imports = MigrationWriter.serialize("foobar")
        self.assertEqual(string, "'foobar'")
        self.assertSerializedEqual({1: 2})
        self.assertSerializedEqual(["a", 2, True, None])
        self.assertSerializedEqual(set([2, 3, "eighty"]))
        self.assertSerializedEqual({"lalalala": ["yeah", "no", "maybe"]})
        self.assertSerializedEqual(_('Hello'))
        # Functions
        with six.assertRaisesRegex(self, ValueError, 'Cannot serialize function: lambda'):
            self.assertSerializedEqual(lambda x: 42)
        self.assertSerializedEqual(models.SET_NULL)
        string, imports = MigrationWriter.serialize(models.SET(42))
        self.assertEqual(string, 'models.SET(42)')
        self.serialize_round_trip(models.SET(42))
        # Datetime stuff
        self.assertSerializedEqual(datetime.datetime.utcnow())
        self.assertSerializedEqual(datetime.datetime.utcnow)
        self.assertSerializedEqual(datetime.datetime.today())
        self.assertSerializedEqual(datetime.datetime.today)
        self.assertSerializedEqual(datetime.date.today())
        self.assertSerializedEqual(datetime.date.today)
        with self.assertRaises(ValueError):
            self.assertSerializedEqual(datetime.datetime(2012, 1, 1, 1, 1, tzinfo=get_default_timezone()))
        safe_date = datetime_safe.date(2014, 3, 31)
        string, imports = MigrationWriter.serialize(safe_date)
        self.assertEqual(string, repr(datetime.date(2014, 3, 31)))
        self.assertEqual(imports, {'import datetime'})
        safe_datetime = datetime_safe.datetime(2014, 3, 31, 16, 4, 31)
        string, imports = MigrationWriter.serialize(safe_datetime)
        self.assertEqual(string, repr(datetime.datetime(2014, 3, 31, 16, 4, 31)))
        self.assertEqual(imports, {'import datetime'})
        # Classes
        validator = RegexValidator(message="hello")
        string, imports = MigrationWriter.serialize(validator)
        self.assertEqual(string, "django.core.validators.RegexValidator(message='hello')")
        self.serialize_round_trip(validator)
        validator = EmailValidator(message="hello")  # Test with a subclass.
        string, imports = MigrationWriter.serialize(validator)
        self.assertEqual(string, "django.core.validators.EmailValidator(message='hello')")
        self.serialize_round_trip(validator)
        validator = deconstructible(path="custom.EmailValidator")(EmailValidator)(message="hello")
        string, imports = MigrationWriter.serialize(validator)
        self.assertEqual(string, "custom.EmailValidator(message='hello')")
        # Django fields
        self.assertSerializedFieldEqual(models.CharField(max_length=255))
        self.assertSerializedFieldEqual(models.TextField(null=True, blank=True))
        # Setting references
        self.assertSerializedEqual(SettingsReference(settings.AUTH_USER_MODEL, "AUTH_USER_MODEL"))
        self.assertSerializedResultEqual(
            SettingsReference("someapp.model", "AUTH_USER_MODEL"),
            (
                "settings.AUTH_USER_MODEL",
                set(["from django.conf import settings"]),
            )
        )
        self.assertSerializedResultEqual(
            ((x, x * x) for x in range(3)),
            (
                "((0, 0), (1, 1), (2, 4))",
                set(),
            )
        )

    def test_simple_migration(self):
        """
        Tests serializing a simple migration.
        """
        fields = {
            'charfield': models.DateTimeField(default=datetime.datetime.utcnow),
            'datetimefield': models.DateTimeField(default=datetime.datetime.utcnow),
        }

        options = {
            'verbose_name': 'My model',
            'verbose_name_plural': 'My models',
        }

        migration = type(str("Migration"), (migrations.Migration,), {
            "operations": [
                migrations.CreateModel("MyModel", tuple(fields.items()), options, (models.Model,)),
                migrations.CreateModel("MyModel2", tuple(fields.items()), bases=(models.Model,)),
                migrations.CreateModel(name="MyModel3", fields=tuple(fields.items()), options=options, bases=(models.Model,)),
                migrations.DeleteModel("MyModel"),
                migrations.AddField("OtherModel", "datetimefield", fields["datetimefield"]),
            ],
            "dependencies": [("testapp", "some_other_one")],
        })
        writer = MigrationWriter(migration)
        output = writer.as_string()
        # It should NOT be unicode.
        self.assertIsInstance(output, six.binary_type, "Migration as_string returned unicode")
        # We don't test the output formatting - that's too fragile.
        # Just make sure it runs for now, and that things look alright.
        result = self.safe_exec(output)
        self.assertIn("Migration", result)
        # In order to preserve compatibility with Python 3.2 unicode literals
        # prefix shouldn't be added to strings.
        tokens = tokenize.generate_tokens(six.StringIO(str(output)).readline)
        for token_type, token_source, (srow, scol), _, line in tokens:
            if token_type == tokenize.STRING:
                self.assertFalse(
                    token_source.startswith('u'),
                    "Unicode literal prefix found at %d:%d: %r" % (
                        srow, scol, line.strip()
                    )
                )

    def test_migration_path(self):
        test_apps = [
            'migrations.migrations_test_apps.normal',
            'migrations.migrations_test_apps.with_package_model',
        ]

        base_dir = os.path.dirname(os.path.dirname(__file__))

        for app in test_apps:
            with self.modify_settings(INSTALLED_APPS={'append': app}):
                migration = migrations.Migration('0001_initial', app.split('.')[-1])
                expected_path = os.path.join(base_dir, *(app.split('.') + ['migrations', '0001_initial.py']))
                writer = MigrationWriter(migration)
                self.assertEqual(writer.path, expected_path)