diff --git a/wagtail/tests/testapp/migrations/0020_customdocument.py b/wagtail/tests/testapp/migrations/0020_customdocument.py
new file mode 100644
index 000000000..397b8e264
--- /dev/null
+++ b/wagtail/tests/testapp/migrations/0020_customdocument.py
@@ -0,0 +1,40 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.6 on 2017-04-12 18:00
+from __future__ import unicode_literals
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+import taggit.managers
+import wagtail.wagtailcore.models
+import wagtail.wagtailsearch.index
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('taggit', '0002_auto_20150616_2121'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('wagtailcore', '0032_add_bulk_delete_page_permission'),
+        ('tests', '0019_richtextfieldwithfeaturespage'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='CustomDocument',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('title', models.CharField(max_length=255, verbose_name='title')),
+                ('file', models.FileField(upload_to='documents', verbose_name='file')),
+                ('created_at', models.DateTimeField(auto_now_add=True, verbose_name='created at')),
+                ('collection', models.ForeignKey(default=wagtail.wagtailcore.models.get_root_collection_id, on_delete=django.db.models.deletion.CASCADE, related_name='+', to='wagtailcore.Collection', verbose_name='collection')),
+                ('tags', taggit.managers.TaggableManager(blank=True, help_text=None, through='taggit.TaggedItem', to='taggit.Tag', verbose_name='tags')),
+                ('uploaded_by_user', models.ForeignKey(blank=True, editable=False, null=True, on_delete=django.db.models.deletion.SET_NULL, to=settings.AUTH_USER_MODEL, verbose_name='uploaded by user')),
+            ],
+            options={
+                'abstract': False,
+                'verbose_name': 'document',
+            },
+            bases=(wagtail.wagtailsearch.index.Indexed, models.Model),
+        ),
+    ]
diff --git a/wagtail/tests/testapp/models.py b/wagtail/tests/testapp/models.py
index dc62f00fd..9a5853251 100644
--- a/wagtail/tests/testapp/models.py
+++ b/wagtail/tests/testapp/models.py
@@ -30,6 +30,7 @@ from wagtail.wagtailcore.blocks import CharBlock, RichTextBlock
 from wagtail.wagtailcore.fields import RichTextField, StreamField
 from wagtail.wagtailcore.models import Orderable, Page, PageManager
 from wagtail.wagtaildocs.edit_handlers import DocumentChooserPanel
+from wagtail.wagtaildocs.models import AbstractDocument, Document
 from wagtail.wagtailforms.models import AbstractEmailForm, AbstractFormField, AbstractFormSubmission
 from wagtail.wagtailimages.blocks import ImageChooserBlock
 from wagtail.wagtailimages.edit_handlers import ImageChooserPanel
@@ -673,6 +674,10 @@ class CustomRendition(AbstractRendition):
         )
 
 
+class CustomDocument(AbstractDocument):
+    admin_form_fields = Document.admin_form_fields
+
+
 class StreamModel(models.Model):
     body = StreamField([
         ('text', CharBlock()),
diff --git a/wagtail/wagtaildocs/signal_handlers.py b/wagtail/wagtaildocs/signal_handlers.py
index 2c69c6802..55969a1cb 100644
--- a/wagtail/wagtaildocs/signal_handlers.py
+++ b/wagtail/wagtaildocs/signal_handlers.py
@@ -4,7 +4,7 @@ from django import VERSION as DJANGO_VERSION
 from django.db import transaction
 from django.db.models.signals import post_delete
 
-from wagtail.wagtaildocs.models import Document
+from wagtail.wagtaildocs.models import get_document_model
 
 
 TRANSACTION_ON_COMMIT_AVAILABLE = (1, 8) < DJANGO_VERSION[:2]
@@ -22,4 +22,5 @@ def post_delete_file_cleanup(instance, **kwargs):
 
 
 def register_signal_handlers():
+    Document = get_document_model()
     post_delete.connect(post_delete_file_cleanup, sender=Document)
diff --git a/wagtail/wagtaildocs/tests/test_models.py b/wagtail/wagtaildocs/tests/test_models.py
index d195a3b99..1e03b264d 100644
--- a/wagtail/wagtaildocs/tests/test_models.py
+++ b/wagtail/wagtaildocs/tests/test_models.py
@@ -7,6 +7,7 @@ from django.contrib.auth.models import Group, Permission
 from django.core.files.base import ContentFile
 from django.db import transaction
 from django.test import TestCase, TransactionTestCase
+from django.test.utils import override_settings
 
 from wagtail.wagtailcore.models import Collection, GroupCollectionPermission
 from wagtail.wagtaildocs import models, signal_handlers
@@ -152,3 +153,27 @@ class TestFilesDeletedForDefaultModels(TransactionTestCase):
             self.assertTrue(document.file.storage.exists(document.file.name))
             document.delete()
         self.assertFalse(document.file.storage.exists(document.file.name))
+
+
+@override_settings(WAGTAILDOCS_DOCUMENT_MODEL='tests.CustomDocument')
+class TestFilesDeletedForCustomModels(TestFilesDeletedForDefaultModels):
+    def setUp(self):
+        # Required to create root collection because the TransactionTestCase
+        # does not make initial data loaded in migrations available and
+        # serialized_rollback=True causes other problems in the test suite.
+        # ref: https://docs.djangoproject.com/en/1.10/topics/testing/overview/#rollback-emulation
+        Collection.objects.get_or_create(
+            name="Root",
+            path='0001',
+            depth=1,
+            numchild=0,
+        )
+
+        #: Sadly signal receivers only get connected when starting django.
+        #: We will re-attach them here to mimic the django startup behavior
+        #: and get the signals connected to our custom model..
+        signal_handlers.register_signal_handlers()
+
+    def test_document_model(self):
+        cls = get_document_model()
+        self.assertEqual('%s.%s' % (cls._meta.app_label, cls.__name__), 'tests.CustomDocument')