old_contents: from django.test import SimpleTestCase
  from jsonobject.exceptions import BadValueError
  
  from corehq.apps.userreports.reports.specs import ReportColumn
  
  
  class TestReportColumn(SimpleTestCase):
      def testBadAggregation(self):
          with self.assertRaises(BadValueError):
              ReportColumn.wrap({
                  "aggregation": "simple_",
                  "field": "doc_id",
                  "type": "field",
              })
  
new_contents: from django.test import SimpleTestCase
  from jsonobject.exceptions import BadValueError
  
  from corehq.apps.userreports.reports.specs import ReportColumn
  
  
  class TestReportColumn(SimpleTestCase):
      def testBadAggregation(self):
          with self.assertRaises(BadValueError):
              ReportColumn.wrap({
                  "aggregation": "simple_",
                  "field": "doc_id",
                  "type": "field",
              })
  
      def testGoodFormat(self):
          for format in [
              'default',
              'percent_of_total',
          ]:
              self.assertEquals(ReportColumn, type(
                  ReportColumn.wrap({
                      "aggregation": "simple",
                      "field": "doc_id",
                      "format": format,
                      "type": "field",
                  })
              ))
  
      def testBadFormat(self):
          with self.assertRaises(BadValueError):
              ReportColumn.wrap({
                  "aggregation": "simple",
                  "field": "doc_id",
                  "format": "default_",
                  "type": "field",
              })
  
subject: test validation of report column format field