old_contents: import unittest
  from tests.common import load_check
  import time
  
  class TestPostgres(unittest.TestCase):
  
      def testChecks(self):
  
          config = {
              'instances': [
                  {
                  'host': 'localhost',
                  'port': 5432,
                  'username': 'datadog',
                  'password': 'datadog',
                  'dbname': 'datadog_test',
                  'relations': ['persons'],
                  }
              ]
          }
          agentConfig = {
              'version': '0.1',
              'api_key': 'toto'
          }
  
          self.check = load_check('postgres', config, agentConfig)
  
          self.check.run()
          metrics = self.check.get_metrics()
          self.assertTrue(len([m for m in metrics if m[0] == 'postgresql.connections']) == 1, metrics)
          self.assertTrue(len([m for m in metrics if m[0] == 'postgresql.dead_rows']) == 1, metrics)
          self.assertTrue(len([m for m in metrics if m[0] == 'postgresql.live_rows']) == 1, metrics)
          self.assertTrue(3 <= len(metrics) <= 4, metrics)
          self.assertTrue(3 <= len([m for m in metrics if 'db:datadog_test' in str(m[3]['tags']) ]) <= 4, metrics)
          self.assertTrue(len([m for m in metrics if 'table:persons' in str(m[3]['tags'])]) == 2, metrics)
  
          time.sleep(1)
          self.check.run()
          metrics = self.check.get_metrics()
  
          self.assertTrue(23 <= len(metrics) <= 26, metrics)
  
  if __name__ == '__main__':
      unittest.main()
  
new_contents: import unittest
  from tests.common import load_check
  import time
  
  class TestPostgres(unittest.TestCase):
  
      def testChecks(self):
  
          config = {
              'instances': [
                  {
                  'host': 'localhost',
                  'port': 5432,
                  'username': 'datadog',
                  'password': 'datadog',
                  'dbname': 'datadog_test',
                  'relations': ['persons'],
                  }
              ]
          }
          agentConfig = {
              'version': '0.1',
              'api_key': 'toto'
          }
  
          self.check = load_check('postgres', config, agentConfig)
  
          self.check.run()
          metrics = self.check.get_metrics()
          self.assertTrue(len([m for m in metrics if m[0] == 'postgresql.connections']) == 1, metrics)
          self.assertTrue(len([m for m in metrics if m[0] == 'postgresql.dead_rows']) == 1, metrics)
          self.assertTrue(len([m for m in metrics if m[0] == 'postgresql.live_rows']) == 1, metrics)
          self.assertTrue(3 <= len(metrics) <= 4, metrics)
          self.assertTrue(3 <= len([m for m in metrics if 'db:datadog_test' in str(m[3]['tags']) ]) <= 4, metrics)
          self.assertTrue(len([m for m in metrics if 'table:persons' in str(m[3]['tags'])]) == 2, metrics)
  
          time.sleep(1)
          self.check.run()
          metrics = self.check.get_metrics()
  
          self.assertTrue(len(metrics) == 18, metrics)
          self.assertTrue(len([m for m in metrics if 'db:datadog_test' in str(m[3]['tags']) ]) == 18, metrics)
          self.assertTrue(len([m for m in metrics if 'table:persons' in str(m[3]['tags']) ]) == 8, metrics)
  
  if __name__ == '__main__':
      unittest.main()
  
subject: Fix postgresql check