Fixed #21702 -- get_model('app_label.ModelName').

Also added tests for get_model.

django/apps/registry.py

@@ -170,16 +170,22 @@ class Apps(object):
                 include_auto_created, include_deferred, include_swapped)))
         return result
 
-    def get_model(self, app_label, model_name):
+    def get_model(self, app_label, model_name=None):
         """
         Returns the model matching the given app_label and model_name.
 
+        As a shortcut, this function also accepts a single argument in the
+        form <app_label>.<model_name>.
+
         model_name is case-insensitive.
 
         Raises LookupError if no application exists with this label, or no
-        model exists with this name in the application.
+        model exists with this name in the application. Raises ValueError if
+        called with a single argument that doesn't contain exactly one dot.
         """
         self.check_ready()
+        if model_name is None:
+            app_label, model_name = app_label.split('.')
         return self.get_app_config(app_label).get_model(model_name.lower())
 
     def register_model(self, app_label, model):

docs/ref/applications.txt

@@ -274,5 +274,10 @@ Application registry
 .. method:: apps.get_model(app_label, model_name)
 
     Returns the :class:`~django.db.models.Model` with the given ``app_label``
-    and ``model_name``. Raises :exc:`~exceptions.LookupError` if no such
-    application or model exists. ``model_name`` is case-insensitive.
+    and ``model_name``. As a shortcut, this method also accepts a single
+    argument in the form ``app_label.model_name``. ``model_name`` is case-
+    insensitive.
+
+    Raises :exc:`~exceptions.LookupError` if no such application or model
+    exists. Raises :exc:`~exceptions.ValueError` when called with a single
+    argument that doesn't contain exactly one dot.

tests/apps/tests.py

@@ -6,6 +6,7 @@ from unittest import skipUnless
 
 from django.apps import apps
 from django.apps.registry import Apps
+from django.contrib.admin.models import LogEntry
 from django.core.exceptions import ImproperlyConfigured
 from django.db import models
 from django.test import TestCase, override_settings
@@ -99,7 +100,7 @@ class AppsTests(TestCase):
     @override_settings(INSTALLED_APPS=SOME_INSTALLED_APPS)
     def test_get_app_configs(self):
         """
-        Tests get_app_configs().
+        Tests apps.get_app_configs().
         """
         app_configs = apps.get_app_configs()
         self.assertListEqual(
@@ -109,7 +110,7 @@ class AppsTests(TestCase):
     @override_settings(INSTALLED_APPS=SOME_INSTALLED_APPS)
     def test_get_app_config(self):
         """
-        Tests get_app_config().
+        Tests apps.get_app_config().
         """
         app_config = apps.get_app_config('admin')
         self.assertEqual(app_config.name, 'django.contrib.admin')
@@ -122,11 +123,35 @@ class AppsTests(TestCase):
 
     @override_settings(INSTALLED_APPS=SOME_INSTALLED_APPS)
     def test_is_installed(self):
+        """
+        Tests apps.is_installed().
+        """
         self.assertTrue(apps.is_installed('django.contrib.admin'))
         self.assertTrue(apps.is_installed('django.contrib.auth'))
         self.assertTrue(apps.is_installed('django.contrib.staticfiles'))
         self.assertFalse(apps.is_installed('django.contrib.webdesign'))
 
+    @override_settings(INSTALLED_APPS=SOME_INSTALLED_APPS)
+    def test_get_model(self):
+        """
+        Tests apps.get_model().
+        """
+        self.assertEqual(apps.get_model('admin', 'LogEntry'), LogEntry)
+        with self.assertRaises(LookupError):
+            apps.get_model('admin', 'LogExit')
+
+        # App label is case-sensitive, Model name is case-insensitive.
+        self.assertEqual(apps.get_model('admin', 'loGentrY'), LogEntry)
+        with self.assertRaises(LookupError):
+            apps.get_model('Admin', 'LogEntry')
+
+        # A single argument is accepted.
+        self.assertEqual(apps.get_model('admin.LogEntry'), LogEntry)
+        with self.assertRaises(LookupError):
+            apps.get_model('admin.LogExit')
+        with self.assertRaises(ValueError):
+            apps.get_model('admin_LogEntry')
+
     @override_settings(INSTALLED_APPS=['apps.apps.RelabeledAppsConfig'])
     def test_relabeling(self):
         self.assertEqual(apps.get_app_config('relabeled').name, 'apps')