[1.7.x] Used migration framework in GIS test tearDown

Backport of 48c4ea414 from master.

django/contrib/gis/db/backends/postgis/schema.py

@@ -10,6 +10,7 @@ class PostGISSchemaEditor(DatabaseSchemaEditor):
     sql_drop_geometry_column = "SELECT DropGeometryColumn(%(table)s, %(column)s)"
     sql_alter_geometry_column_not_null = "ALTER TABLE %(table)s ALTER COLUMN %(column)s SET NOT NULL"
     sql_add_spatial_index = "CREATE INDEX %(index)s ON %(table)s USING %(index_type)s (%(column)s %(ops)s)"
+    sql_clear_geometry_columns = "DELETE FROM geometry_columns WHERE f_table_name = %(table)s"
 
     def __init__(self, *args, **kwargs):
         super(PostGISSchemaEditor, self).__init__(*args, **kwargs)
@@ -46,7 +47,7 @@ class PostGISSchemaEditor(DatabaseSchemaEditor):
                     self.sql_alter_geometry_column_not_null % {
                         "table": self.quote_name(model._meta.db_table),
                         "column": self.quote_name(field.column),
-                    },
+                    }
                 )
 
         if field.spatial_index:
@@ -83,6 +84,12 @@ class PostGISSchemaEditor(DatabaseSchemaEditor):
             self.execute(sql)
         self.geometry_sql = []
 
+    def delete_model(self, model):
+        super(PostGISSchemaEditor, self).delete_model(model)
+        self.execute(self.sql_clear_geometry_columns % {
+            "table": self.geo_quote_name(model._meta.db_table),
+        })
+
     def add_field(self, model, field):
         super(PostGISSchemaEditor, self).add_field(model, field)
         # Create geometry columns

django/contrib/gis/tests/gis_migrations/test_operations.py

@@ -6,7 +6,6 @@ from django.contrib.gis.tests.utils import HAS_SPATIAL_DB
 from django.db import connection, migrations, models
 from django.db.migrations.migration import Migration
 from django.db.migrations.state import ProjectState
-from django.db.utils import DatabaseError
 from django.test import TransactionTestCase
 
 if HAS_SPATIAL_DB:
@@ -24,15 +23,7 @@ class OperationTests(TransactionTestCase):
 
     def tearDown(self):
         # Delete table after testing
-        with connection.cursor() as cursor:
-            try:
-                cursor.execute("DROP TABLE %s" % connection.ops.quote_name("gis_neighborhood"))
-            except DatabaseError:
-                pass
-            else:
-                if HAS_GEOMETRY_COLUMNS:
-                    cursor.execute("DELETE FROM geometry_columns WHERE %s = %%s" % (
-                        GeometryColumns.table_name_col(),), ["gis_neighborhood"])
+        self.apply_operations('gis', self.current_state, [migrations.DeleteModel("Neighborhood")])
         super(OperationTests, self).tearDown()
 
     def get_table_description(self, table):
@@ -84,6 +75,7 @@ class OperationTests(TransactionTestCase):
                 GeometryColumns.objects.filter(**{GeometryColumns.table_name_col(): "gis_neighborhood"}).count(),
                 2
             )
+        self.current_state = new_state
 
     def test_remove_gis_field(self):
         """
@@ -103,3 +95,4 @@ class OperationTests(TransactionTestCase):
                 GeometryColumns.objects.filter(**{GeometryColumns.table_name_col(): "gis_neighborhood"}).count(),
                 0
             )
+        self.current_state = new_state