text: """Tests for django.db.backends.utils"""
  from decimal import Decimal, Rounded
  
  from django.db.backends.utils import format_number, truncate_name
  from django.test import SimpleTestCase
  
  
  class TestUtils(SimpleTestCase):
  
      def test_truncate_name(self):
          self.assertEqual(truncate_name('some_table', 10), 'some_table')
          self.assertEqual(truncate_name('some_long_table', 10), 'some_la38a')
          self.assertEqual(truncate_name('some_long_table', 10, 3), 'some_loa38')
          self.assertEqual(truncate_name('some_long_table'), 'some_long_table')
          # "user"."table" syntax
          self.assertEqual(truncate_name('username"."some_table', 10), 'username"."some_table')
          self.assertEqual(truncate_name('username"."some_long_table', 10), 'username"."some_la38a')
          self.assertEqual(truncate_name('username"."some_long_table', 10, 3), 'username"."some_loa38')
  
      def test_format_number(self):
          def equal(value, max_d, places, result):
              self.assertEqual(format_number(Decimal(value), max_d, places), result)
  
          equal('0', 12, 3, '0.000')
          equal('0', 12, 8, '0.00000000')
          equal('1', 12, 9, '1.000000000')
          equal('0.00000000', 12, 8, '0.00000000')
          equal('0.000000004', 12, 8, '0.00000000')
          equal('0.000000008', 12, 8, '0.00000001')
          equal('0.000000000000000000999', 10, 8, '0.00000000')
          equal('0.1234567890', 12, 10, '0.1234567890')
          equal('0.1234567890', 12, 9, '0.123456789')
          equal('0.1234567890', 12, 8, '0.12345679')
          equal('0.1234567890', 12, 5, '0.12346')
          equal('0.1234567890', 12, 3, '0.123')
          equal('0.1234567890', 12, 1, '0.1')
          equal('0.1234567890', 12, 0, '0')
          equal('0.1234567890', None, 0, '0')
          equal('1234567890.1234567890', None, 0, '1234567890')
          equal('1234567890.1234567890', None, 2, '1234567890.12')
          equal('0.1234', 5, None, '0.1234')
          equal('123.12', 5, None, '123.12')
  
          with self.assertRaises(Rounded):
              equal('0.1234567890', 5, None, '0.12346')
          with self.assertRaises(Rounded):
              equal('1234567890.1234', 5, None, '1234600000')
  