text: from django.contrib.gis import admin
  from django.contrib.gis.geos import Point
  from django.test import TestCase, override_settings
  from django.test.utils import patch_logger
  
  from .admin import UnmodifiableAdmin
  from .models import City, site
  
  
  @override_settings(ROOT_URLCONF='django.contrib.gis.tests.geoadmin.urls')
  class GeoAdminTest(TestCase):
  
      def test_ensure_geographic_media(self):
          geoadmin = site._registry[City]
          admin_js = geoadmin.media.render_js()
          self.assertTrue(any(geoadmin.openlayers_url in js for js in admin_js))
  
      def test_olmap_OSM_rendering(self):
          delete_all_btn = """<a href="javascript:geodjango_point.clearFeatures()">Delete all Features</a>"""
  
          original_geoadmin = site._registry[City]
          params = original_geoadmin.get_map_widget(City._meta.get_field('point')).params
          result = original_geoadmin.get_map_widget(City._meta.get_field('point'))(
          ).render('point', Point(-79.460734, 40.18476), params)
          self.assertIn(
              """geodjango_point.layers.base = new OpenLayers.Layer.OSM("OpenStreetMap (Mapnik)");""",
              result)
  
          self.assertIn(delete_all_btn, result)
  
          site.unregister(City)
          site.register(City, UnmodifiableAdmin)
          try:
              geoadmin = site._registry[City]
              params = geoadmin.get_map_widget(City._meta.get_field('point')).params
              result = geoadmin.get_map_widget(City._meta.get_field('point'))(
              ).render('point', Point(-79.460734, 40.18476), params)
  
              self.assertNotIn(delete_all_btn, result)
          finally:
              site.unregister(City)
              site.register(City, original_geoadmin.__class__)
  
      def test_olmap_WMS_rendering(self):
          geoadmin = admin.GeoModelAdmin(City, site)
          result = geoadmin.get_map_widget(City._meta.get_field('point'))(
          ).render('point', Point(-79.460734, 40.18476))
          self.assertIn(
              """geodjango_point.layers.base = new OpenLayers.Layer.WMS("OpenLayers WMS", """
              """"http://vmap0.tiles.osgeo.org/wms/vmap0", {layers: 'basic', format: 'image/jpeg'});""",
              result)
  
      def test_olwidget_has_changed(self):
          """
          Changes are accurately noticed by OpenLayersWidget.
          """
          geoadmin = site._registry[City]
          form = geoadmin.get_changelist_form(None)()
          has_changed = form.fields['point'].has_changed
  
          initial = Point(13.4197458572965953, 52.5194108501149799, srid=4326)
          data_same = "SRID=3857;POINT(1493879.2754093995 6894592.019687599)"
          data_almost_same = "SRID=3857;POINT(1493879.2754093990 6894592.019687590)"
          data_changed = "SRID=3857;POINT(1493884.0527237 6894593.8111804)"
  
          self.assertTrue(has_changed(None, data_changed))
          self.assertTrue(has_changed(initial, ""))
          self.assertFalse(has_changed(None, ""))
          self.assertFalse(has_changed(initial, data_same))
          self.assertFalse(has_changed(initial, data_almost_same))
          self.assertTrue(has_changed(initial, data_changed))
  
      def test_olwidget_empty_string(self):
          geoadmin = site._registry[City]
          form = geoadmin.get_changelist_form(None)({'point': ''})
          with patch_logger('django.contrib.gis', 'error') as logger_calls:
              output = str(form['point'])
          self.assertInHTML(
              '<textarea id="id_point" class="vWKTField required" cols="150"'
              ' rows="10" name="point"></textarea>',
              output
          )
          self.assertEqual(logger_calls, [])
  
      def test_olwidget_invalid_string(self):
          geoadmin = site._registry[City]
          form = geoadmin.get_changelist_form(None)({'point': 'INVALID()'})
          with patch_logger('django.contrib.gis', 'error') as logger_calls:
              output = str(form['point'])
          self.assertInHTML(
              '<textarea id="id_point" class="vWKTField required" cols="150"'
              ' rows="10" name="point"></textarea>',
              output
          )
          self.assertEqual(len(logger_calls), 1)
          self.assertEqual(
              logger_calls[0],
              "Error creating geometry from value 'INVALID()' (String input "
              "unrecognized as WKT EWKT, and HEXEWKB.)"
          )
  