Cleaned up and refactored ModelAdmin.formfield_for_dbfield:

* The new method uses an admin configuration option (`formfield_overrides`); this makes custom admin widgets especially easy.
  * Refactored what was left of `formfield_for_dbfield` into a handful of smaller methods so that it's easier to hook in and return custom fields where needed.
  * These `formfield_for_*` methods now pass around `request` so that you can easily modify fields based on request (as in #3987).

Fixes #8306, #3987, #9148.

Thanks to James Bennet for the original patch; Alex Gaynor and Brian Rosner also contributed.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@9760 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/regressiontests/admin_widgets/tests.py

@@ -0,0 +1,112 @@
+from django import forms
+from django.contrib import admin
+from django.contrib.admin import widgets
+from unittest import TestCase
+from django.test import TestCase as DjangoTestCase
+import models
+
+class AdminFormfieldForDBFieldTests(TestCase):
+    """
+    Tests for correct behavior of ModelAdmin.formfield_for_dbfield
+    """
+
+    def assertFormfield(self, model, fieldname, widgetclass, **admin_overrides):
+        """
+        Helper to call formfield_for_dbfield for a given model and field name
+        and verify that the returned formfield is appropriate.
+        """
+        # Override any settings on the model admin
+        class MyModelAdmin(admin.ModelAdmin): pass
+        for k in admin_overrides:
+            setattr(MyModelAdmin, k, admin_overrides[k])
+        
+        # Construct the admin, and ask it for a formfield
+        ma = MyModelAdmin(model, admin.site)
+        ff = ma.formfield_for_dbfield(model._meta.get_field(fieldname), request=None)
+        
+        # "unwrap" the widget wrapper, if needed
+        if isinstance(ff.widget, widgets.RelatedFieldWidgetWrapper):
+            widget = ff.widget.widget
+        else:
+            widget = ff.widget
+        
+        # Check that we got a field of the right type
+        self.assert_(
+            isinstance(widget, widgetclass), 
+            "Wrong widget for %s.%s: expected %s, got %s" % \
+                (model.__class__.__name__, fieldname, widgetclass, type(widget))
+        )
+            
+        # Return the formfield so that other tests can continue
+        return ff
+    
+    def testDateField(self):
+        self.assertFormfield(models.Event, 'date', widgets.AdminDateWidget)
+        
+    def testDateTimeField(self):
+        self.assertFormfield(models.Member, 'birthdate', widgets.AdminSplitDateTime)
+        
+    def testTimeField(self):
+        self.assertFormfield(models.Event, 'start_time', widgets.AdminTimeWidget)
+
+    def testTextField(self):
+        self.assertFormfield(models.Event, 'description', widgets.AdminTextareaWidget)
+    
+    def testURLField(self):
+        self.assertFormfield(models.Event, 'link', widgets.AdminURLFieldWidget)
+
+    def testIntegerField(self):
+        self.assertFormfield(models.Event, 'min_age', widgets.AdminIntegerFieldWidget)
+        
+    def testCharField(self):
+        self.assertFormfield(models.Member, 'name', widgets.AdminTextInputWidget)
+        
+    def testFileField(self):
+        self.assertFormfield(models.Album, 'cover_art', widgets.AdminFileWidget)
+        
+    def testForeignKey(self):
+        self.assertFormfield(models.Event, 'band', forms.Select)
+        
+    def testRawIDForeignKey(self):
+        self.assertFormfield(models.Event, 'band', widgets.ForeignKeyRawIdWidget,
+                             raw_id_fields=['band'])
+    
+    def testRadioFieldsForeignKey(self):
+        ff = self.assertFormfield(models.Event, 'band', widgets.AdminRadioSelect, 
+                                  radio_fields={'band':admin.VERTICAL})
+        self.assertEqual(ff.empty_label, None)
+        
+    def testManyToMany(self):
+        self.assertFormfield(models.Band, 'members', forms.SelectMultiple)
+    
+    def testRawIDManyTOMany(self):
+        self.assertFormfield(models.Band, 'members', widgets.ManyToManyRawIdWidget,
+                             raw_id_fields=['members'])
+    
+    def testFilteredManyToMany(self):
+        self.assertFormfield(models.Band, 'members', widgets.FilteredSelectMultiple,
+                             filter_vertical=['members'])
+    
+    def testFormfieldOverrides(self):
+        self.assertFormfield(models.Event, 'date', forms.TextInput, 
+                             formfield_overrides={'widget': forms.TextInput})
+                             
+    def testFieldWithChoices(self):
+        self.assertFormfield(models.Member, 'gender', forms.Select)
+        
+    def testChoicesWithRadioFields(self):
+        self.assertFormfield(models.Member, 'gender', widgets.AdminRadioSelect, 
+                             radio_fields={'gender':admin.VERTICAL})
+
+
+class AdminFormfieldForDBFieldWithRequestTests(DjangoTestCase):
+    fixtures = ["admin-widgets-users.xml"]
+    
+    def testFilterChoicesByRequestUser(self):
+        """
+        Ensure the user can only see their own cars in the foreign key dropdown.
+        """
+        self.client.login(username="super", password="secret")
+        response = self.client.get("/widget_admin/admin_widgets/cartire/add/")
+        self.assert_("BMW M3" not in response.content)
+        self.assert_("Volkswagon Passat" in response.content)