Made m2m fields form help_text munging specific to admin widgets.

Refs #9321 and follow-up to e80de93af6.

tests/admin_widgets/tests.py

@@ -19,6 +19,7 @@ from django.core.files.uploadedfile import SimpleUploadedFile
 from django.db.models import CharField, DateField
 from django.test import TestCase as DjangoTestCase
 from django.test import override_settings
+from django.utils import six
 from django.utils import translation
 
 from . import models
@@ -168,6 +169,17 @@ class AdminFormfieldForDBFieldTests(TestCase):
     def testInheritance(self):
         self.assertFormfield(models.Album, 'backside_art', widgets.AdminFileWidget)
 
+    def test_m2m_widgets(self):
+        """m2m fields help text as it applies to admin app (#9321)."""
+        class AdvisorAdmin(admin.ModelAdmin):
+            filter_vertical = ['companies']
+
+        self.assertFormfield(models.Advisor, 'companies', widgets.FilteredSelectMultiple,
+                             filter_vertical=['companies'])
+        ma = AdvisorAdmin(models.Advisor, admin.site)
+        f = ma.formfield_for_dbfield(models.Advisor._meta.get_field('companies'), request=None)
+        self.assertEqual(six.text_type(f.help_text), 'Hold down "Control", or "Command" on a Mac, to select more than one.')
+
 
 @override_settings(PASSWORD_HASHERS=('django.contrib.auth.hashers.SHA1PasswordHasher',))
 class AdminFormfieldForDBFieldWithRequestTests(DjangoTestCase):