Fixed #18271 -- Changed stage at which TransactionTestCase flushes DB tables.

Previously, the flush was done before the test case execution and now
it is performed after it.

Other changes to the testing infrastructure include:

* TransactionTestCase now doesn't reset autoincrement sequences either
  (previous behavior can achieved by using `reset_sequences`.)
  With this, no implicit such reset is performed by any of the provided
  TestCase classes.

* New ordering of test cases: All unittest tes cases are run first and
  doctests are run at the end.

THse changes could be backward-incompatible with test cases that relied
on some kind of state being preserved between tests. Please read the
relevant sections of the release notes and testing documentation for
further details.

Thanks Andreas Pelme for the initial patch. Karen Tracey and Anssi
Kääriäinen for the feedback and Anssi for reviewing.

This also fixes #12408.

1 files changed, 19 insertions, 15 deletions

diff --git a/django/db/backends/postgresql_psycopg2/operations.py b/django/db/backends/postgresql_psycopg2/operations.py
index e93a15512b..40fe629110 100644
--- a/django/db/backends/postgresql_psycopg2/operations.py
+++ b/django/db/backends/postgresql_psycopg2/operations.py
@@ -85,25 +85,29 @@ class DatabaseOperations(BaseDatabaseOperations):
                 (style.SQL_KEYWORD('TRUNCATE'),
                     style.SQL_FIELD(', '.join([self.quote_name(table) for table in tables]))
             )]
-
-            # 'ALTER SEQUENCE sequence_name RESTART WITH 1;'... style SQL statements
-            # to reset sequence indices
-            for sequence_info in sequences:
-                table_name = sequence_info['table']
-                column_name = sequence_info['column']
-                if not (column_name and len(column_name) > 0):
-                    # This will be the case if it's an m2m using an autogenerated
-                    # intermediate table (see BaseDatabaseIntrospection.sequence_list)
-                    column_name = 'id'
-                sql.append("%s setval(pg_get_serial_sequence('%s','%s'), 1, false);" % \
-                    (style.SQL_KEYWORD('SELECT'),
-                    style.SQL_TABLE(self.quote_name(table_name)),
-                    style.SQL_FIELD(column_name))
-                )
+            sql.extend(self.sequence_reset_by_name_sql(style, sequences))
             return sql
         else:
             return []
 
+    def sequence_reset_by_name_sql(self, style, sequences):
+        # 'ALTER SEQUENCE sequence_name RESTART WITH 1;'... style SQL statements
+        # to reset sequence indices
+        sql = []
+        for sequence_info in sequences:
+            table_name = sequence_info['table']
+            column_name = sequence_info['column']
+            if not (column_name and len(column_name) > 0):
+                # This will be the case if it's an m2m using an autogenerated
+                # intermediate table (see BaseDatabaseIntrospection.sequence_list)
+                column_name = 'id'
+            sql.append("%s setval(pg_get_serial_sequence('%s','%s'), 1, false);" % \
+                (style.SQL_KEYWORD('SELECT'),
+                style.SQL_TABLE(self.quote_name(table_name)),
+                style.SQL_FIELD(column_name))
+            )
+        return sql
+
     def tablespace_sql(self, tablespace, inline=False):
         if inline:
             return "USING INDEX TABLESPACE %s" % self.quote_name(tablespace)