feat: import/export dashboards via cli (#5991)

* feat: import/export dashboards via cli

* style: fixed lint error

* test: added test for import and export util

* test: removing import test as it is causing integrity issues

Import is a wrapper around exist functionality so we can go ahead without a test or mock the actual db operation using https://docs.python.org/3/library/unittest.mock.html

And validate the wrapper operations only.

* test: remove test data file

* test: removed usage of reserved keyword id

tests/import_export_tests.py

@@ -10,7 +10,7 @@ import unittest
 
 from sqlalchemy.orm.session import make_transient
 
-from superset import db, utils
+from superset import dashboard_import_export_util, db, utils
 from superset.connectors.druid.models import (
     DruidColumn, DruidDatasource, DruidMetric,
 )
@@ -149,6 +149,9 @@ class ImportExportTests(SupersetTestCase):
         return db.session.query(SqlaTable).filter_by(
             table_name=name).first()
 
+    def get_num_dashboards(self):
+        return db.session.query(models.Dashboard).count()
+
     def assert_dash_equals(self, expected_dash, actual_dash,
                            check_position=True):
         self.assertEquals(expected_dash.slug, actual_dash.slug)
@@ -547,6 +550,34 @@ class ImportExportTests(SupersetTestCase):
         self.assert_datasource_equals(
             copy_datasource, self.get_datasource(imported_id))
 
+    def test_export_dashboards_util(self):
+        dashboards_json_dump = dashboard_import_export_util.export_dashboards(
+            db.session)
+        dashboards_objects = json.loads(
+            dashboards_json_dump,
+            object_hook=utils.decode_dashboards,
+        )
+
+        exported_dashboards = dashboards_objects['dashboards']
+        for dashboard in exported_dashboards:
+            id_ = dashboard.id
+            dash = self.get_dash(id_)
+            self.assert_dash_equals(dash, dashboard)
+            self.assertEquals(
+                dash.id, json.loads(
+                    dashboard.json_metadata,
+                    object_hook=utils.decode_dashboards,
+                )['remote_id'],
+            )
+        numDasboards = self.get_num_dashboards()
+        self.assertEquals(numDasboards, len(exported_dashboards))
+
+        exported_tables = dashboards_objects['datasources']
+        for exported_table in exported_tables:
+            id_ = exported_table.id
+            table = self.get_table(id_)
+            self.assert_table_equals(table, exported_table)
+
 
 if __name__ == '__main__':
     unittest.main()