Use django's test case that works with database correctry without the need to flush transactions manually. Removed some workarounds that were used before

boards/tests.py

@@ -1,5 +1,5 b''
 # coding=utf-8
-from django.utils.unittest import TestCase
+from django.test import TestCase
 from django.test.client import Client
 import time
 
@@ -47,8 +47,6 b' class BoardTests(TestCase):'
 
         self.assertFalse(Post.objects.exists(post_id))
 
-    # Authentication tests
-
     def test_get_thread(self):
         opening_post = self._create_post()
 
@@ -92,8 +90,6 b' class BoardTests(TestCase):'
         captcha_enabled = settings.ENABLE_CAPTCHA
         settings.ENABLE_CAPTCHA = False
 
-        Post.objects.all().delete()
-
         client = Client()
 
         valid_tags = u'tag1 tag_2 тег_3'
@@ -136,9 +132,6 b' class BoardTests(TestCase):'
     def test_404(self):
         """Test receiving error 404 when opening a non-existent page"""
 
-        Post.objects.all().delete()
-        Tag.objects.all().delete()
-
         tag_name = u'test_tag'
         tag = Tag.objects.create(name=tag_name)
         client = Client()