created django_use_model marker for testing unmanaged models

Author: Jakub Owczarski

docs/helpers.rst

@@ -94,6 +94,32 @@ on what marks are and for notes on using_ them.
          client('some-url-with-invalid-template-vars')
 
 
+``pytest.mark.django_use_model`` - force model creation for unmanaged models
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. py:function:: pytest.mark.django_use_model(model)
+
+   :type model: django model or list of django models
+   :param model:
+     Model or models to be created, should be used only with models that
+     have ``Meta.managed = False``
+
+   This will create requested model(s) for the scope of the marker.
+   Allows testing of unmanaged models that are normally not created.
+
+   .. note::
+
+      To access database you still have to request access by using
+      ``pytest.mark.django_db``
+
+  Example usage::
+
+     @pytest.mark.django_db
+     @pytest.mark.django_use_model(Unmanaged)
+     def test_unmanaged():
+        assert Unmanaged.objects.count() >= 0
+
+
 Fixtures
 --------
 

pytest_django/plugin.py

@@ -168,6 +168,10 @@ def pytest_load_initial_conftests(early_config, parser, args):
         'the `urls` attribute of Django `TestCase` objects.  *modstr* is '
         'a string specifying the module of a URL config, e.g. '
         '"my_app.test_urls".')
+    early_config.addinivalue_line(
+        'markers',
+        'django_use_model(model): force model creation, '
+        'even for unmanaged models. Model(s) are deleted at the end of scope')
 
     options = parser.parse_known_args(args)
 
@@ -297,6 +301,48 @@ def _django_db_marker(request):
             request.getfuncargvalue('db')
 
 
+@pytest.fixture(autouse=True)
+def _django_use_model(request):
+    """Implement ``django_use_model`` marker.
+
+    Marker creates unmanaged models that normally aren't created.
+    Destroys it at the end of marked scope.
+
+    Note that you still need to use ``django_db`` marker before this one.
+    The test unit should be decorated:
+
+    @pytest.mark.django_db
+    @pytest.mark.django_use_model(model)
+
+    :model: ModelClass, one or many
+    """
+    marker = request.keywords.get('django_use_model', None)
+    if not marker:
+        return
+    from django.db import connection
+
+    model = request.getfuncargvalue('model')
+
+    if isinstance(model, (list, tuple)):
+        models = model
+    else:
+        models = (model,)
+
+    with contextlib.closing(connection.schema_editor()) as schema:
+        schema.deferred_sql = []
+        for model_class in models:
+            if not hasattr(model, '_meta'):
+                raise ValueError('"model" must be a valid model class')
+            schema.create_model(model_class)
+
+    def drop():
+        with contextlib.closing(connection.schema_editor()) as schema:
+            for model_class in models:
+                schema.delete_model(model_class)
+
+    request.addfinalizer(drop)
+
+
 @pytest.fixture(autouse=True, scope='class')
 def _django_setup_unittest(request, _django_cursor_wrapper):
     """Setup a django unittest, internal to pytest-django."""

pytest_django_test/app/models.py

@@ -3,3 +3,10 @@
 
 class Item(models.Model):
     name = models.CharField(max_length=100)
+
+
+class Unmanaged(models.Model):
+    name = models.CharField(max_length=100)
+
+    class Meta:
+        managed = False

tests/test_database.py

@@ -1,10 +1,10 @@
 from __future__ import with_statement
 
 import pytest
-from django.db import connection, transaction
+from django.db import connection, transaction, DatabaseError
 from django.test.testcases import connections_support_transactions
 
-from pytest_django_test.app.models import Item
+from pytest_django_test.app.models import Item, Unmanaged
 
 
 def noop_transactions():
@@ -164,6 +164,28 @@ def test_transactions_enabled(self):
         assert not noop_transactions()
 
 
+@pytest.mark.django_db
+class TestUseModel:
+    """Tests for django_use_model marker"""
+
+    def test_unmanaged_missing(self):
+        """Test that Unmanaged model is not created by default"""
+        with pytest.raises(DatabaseError):
+            # If table does not exists, django will raise DatabaseError
+            # but the message will depend on the backend.
+            # Probably nothing else can be asserted here.
+            Unmanaged.objects.exists()
+
+    @pytest.mark.django_use_model(Unmanaged)
+    def test_unmanaged_created(self):
+        """Make sure unmanaged models are created"""
+        assert Unmanaged.objects.count() == 0
+
+    def test_unmanaged_destroyed(self):
+        """Test that Unmanaged model was destroyed after last use"""
+        self.test_unmanaged_missing()
+
+
 def test_unittest_interaction(django_testdir):
     "Test that (non-Django) unittests cannot access the DB."