Remove duplication

django_migration_linter/__init__.py

@@ -13,3 +13,4 @@
 # limitations under the License.
 
 from .migration_linter import *  # noqa
+from .constants import *  # noqa

django_migration_linter/constants.py

@@ -0,0 +1,4 @@
+# Can be used to mark ignored migrations.
+# This is a noop for SQL. Comments would be better.
+# But comments are stripped by RunSQL
+IGNORE_MIGRATION = ("SELECT 'dml-ignore'", )

django_migration_linter/migration_linter.py

@@ -24,11 +24,6 @@ from .sql_analyser import analyse_sql_statements
 
 logger = logging.getLogger(__name__)
 
-# Can be used to mark ignored migrations.
-# This is a noop for SQL. Comments would be better.
-# But comments are stripped by RunSQL
-IGNORE_MIGRATION = ("SELECT 'dml-ignore'", )
-
 
 class MigrationLinter(object):
     MIGRATION_FOLDER_NAME = 'migrations'

django_migration_linter/sql_analyser.py

@@ -15,6 +15,8 @@
 import re
 import logging
 
+from django_migration_linter.constants import IGNORE_MIGRATION
+
 logger = logging.getLogger(__name__)
 
 
@@ -65,7 +67,7 @@ migration_tests = (
         'err_msg': ''
     }, {
         'code': 'IGNORED_MIGRATION',
-        'fn': lambda sql, **kw: re.search('dml-ignore', sql),
+        'fn': lambda sql, **kw: re.search(IGNORE_MIGRATION[0], sql),
         'err_msg': '',
     }
 )