Chore: organize tests

tests/fields/test_alias_fields.py

@@ -2,8 +2,8 @@ import unittest
 from datetime import date
 
 from clickhouse_orm.database import Database
-from clickhouse_orm.engines import *
+from clickhouse_orm.engines import MergeTree
-from clickhouse_orm.fields import *
+from clickhouse_orm.fields import DateField, Int32Field, StringField
 from clickhouse_orm.funcs import F
 from clickhouse_orm.models import NO_VALUE, Model
 
@@ -67,7 +67,7 @@ class ModelWithAliasFields(Model):
     date_field = DateField()
     str_field = StringField()
 
-    alias_str = StringField(alias=u"str_field")
+    alias_str = StringField(alias="str_field")
     alias_int = Int32Field(alias="int_field")
     alias_date = DateField(alias="date_field")
     alias_func = Int32Field(alias=F.toYYYYMM(date_field))