Fixed issue where build would break on django 1.6 due to different method of importing models

Author: Ross Mechanic

simple_history/tests/external/models/model1.py

@@ -0,0 +1,12 @@
+from __future__ import unicode_literals
+
+from django.db import models
+from simple_history.models import HistoricalRecords
+
+
+class AbstractExternal(models.Model):
+    history = HistoricalRecords(inherit=True)
+
+    class Meta:
+        abstract = True
+        app_label = 'external'

simple_history/tests/external/models/model2.py

@@ -10,11 +10,3 @@ class ExternalModel2(models.Model):
 
     class Meta:
         app_label = 'external'
-
-
-class AbstractExternal(models.Model):
-    history = HistoricalRecords(inherit=True)
-
-    class Meta:
-        abstract = True
-        app_label = 'external'

simple_history/tests/models.py

@@ -1,12 +1,30 @@
 from __future__ import unicode_literals
 
 from django.db import models
+from django import VERSION
 
 from simple_history.models import HistoricalRecords
 from simple_history import register
 
 from .custom_user.models import CustomUser as User
-from .external.models.model2 import AbstractExternal
+
+try:
+    from django.apps import apps
+except ImportError:  # Django < 1.7
+    from django.db.models import get_model
+else:
+    get_model = apps.get_model
+
+# 1.6 has different way of importing models
+if VERSION[:3] >= (1, 7, 0):
+    from .external.models.model1 import AbstractExternal
+else:
+    class AbstractExternal(models.Model):
+        history = HistoricalRecords(inherit=True)
+
+        class Meta:
+            abstract = True
+            app_label = 'external'
 
 
 class Poll(models.Model):