new_contents: 
  
  class TestSchemaErrors(object):
  
      def test_install_empty_object(self, session):
          result = session.app.post_json("/api/mon/install/", params=dict(),
                                         expect_errors=True)
          message = result.json['message']
          assert message.endswith('an empty dictionary object was provided')
  
      def test_host_is_invalid(self, session):
          params = {'hosts': ''}
          result = session.app.post_json("/api/mon/install/", params=params,
                                         expect_errors=True)
          message = result.json['message']
          assert "hosts" in message
          assert message.endswith(
                  "failed validation, requires format: ['host1', 'host2']"
          )
  
      def test_release_is_wrong_type(self, session):
          params = {'hosts': ['node1'], 'release': False}
          result = session.app.post_json("/api/mon/install/", params=params,
                                         expect_errors=True)
          message = result.json['message']
          assert message.endswith('not of type string')
          assert 'release' in message
  
subject: test the error handling of schema failures