tests: fix DeprecationWarning: invalid escape sequence \w

Author: blueyed

tests/test_fixtures.py

@@ -578,7 +578,7 @@ class Migration(migrations.Migration):
                 ('password', models.CharField(max_length=128, verbose_name='password')),
                 ('last_login', models.DateTimeField(null=True, verbose_name='last login', blank=True)),
                 ('is_superuser', models.BooleanField(default=False, help_text='Designates that this user has all permissions without explicitly assigning them.', verbose_name='superuser status')),
-                ('username', models.CharField(error_messages={'unique': 'A user with that username already exists.'}, max_length=30, validators=[django.core.validators.RegexValidator('^[\\w.@+-]+$', 'Enter a valid username. This value may contain only letters, numbers and @/./+/-/_ characters.', 'invalid')], help_text='Required. 30 characters or fewer. Letters, digits and @/./+/-/_ only.', unique=True, verbose_name='username')),
+                ('username', models.CharField(error_messages={'unique': 'A user with that username already exists.'}, max_length=30, validators=[django.core.validators.RegexValidator(r'^[\\w.@+-]+$', 'Enter a valid username. This value may contain only letters, numbers and @/./+/-/_ characters.', 'invalid')], help_text='Required. 30 characters or fewer. Letters, digits and @/./+/-/_ only.', unique=True, verbose_name='username')),
                 ('first_name', models.CharField(max_length=30, verbose_name='first name', blank=True)),
                 ('last_name', models.CharField(max_length=30, verbose_name='last name', blank=True)),
                 ('email', models.EmailField(max_length=254, verbose_name='email address', blank=True)),