Improved test isolation of the admin tests and assigned custom admin sites to

prevent test order dependant failures.

This involves introducing usage of `TestCase.urls` and implementing proper
admin.py modules for some of the test apps.

Thanks Florian Apolloner for finding the issue and contributing the patch.

Refs #15294 (it solves these problems so the fix for that ticket we are going
to commit doesn't introduce obscure and hard to reproduce test failures when
running the Django test suite.)

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16856 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/regressiontests/admin_changelist/admin.py

@@ -0,0 +1,67 @@
+from django.core.paginator import Paginator
+from django.contrib import admin
+
+from models import (Child, Parent, Genre, Band, Musician, Group, Quartet,
+    Membership, ChordsMusician, ChordsBand, Invitation)
+
+site = admin.AdminSite(name="admin")
+
+class CustomPaginator(Paginator):
+    def __init__(self, queryset, page_size, orphans=0, allow_empty_first_page=True):
+        super(CustomPaginator, self).__init__(queryset, 5, orphans=2,
+            allow_empty_first_page=allow_empty_first_page)
+
+
+class ParentAdmin(admin.ModelAdmin):
+    list_filter = ['child__name']
+    search_fields = ['child__name']
+
+
+class ChildAdmin(admin.ModelAdmin):
+    list_display = ['name', 'parent']
+    list_per_page = 10
+
+    def queryset(self, request):
+        return super(ChildAdmin, self).queryset(request).select_related("parent__name")
+
+
+class CustomPaginationAdmin(ChildAdmin):
+    paginator = CustomPaginator
+
+
+class FilteredChildAdmin(admin.ModelAdmin):
+    list_display = ['name', 'parent']
+    list_per_page = 10
+
+    def queryset(self, request):
+        return super(FilteredChildAdmin, self).queryset(request).filter(
+            name__contains='filtered')
+
+
+class BandAdmin(admin.ModelAdmin):
+    list_filter = ['genres']
+
+
+class GroupAdmin(admin.ModelAdmin):
+    list_filter = ['members']
+
+
+class QuartetAdmin(admin.ModelAdmin):
+    list_filter = ['members']
+
+
+class ChordsBandAdmin(admin.ModelAdmin):
+    list_filter = ['members']
+
+
+class DynamicListDisplayChildAdmin(admin.ModelAdmin):
+    list_display = ('name', 'parent')
+
+    def get_list_display(self, request):
+        my_list_display = list(self.list_display)
+        if request.user.username == 'noparents':
+            my_list_display.remove('parent')
+
+        return my_list_display
+
+site.register(Child, DynamicListDisplayChildAdmin)