def test_get_conn_uri(self, mock_secret_client, mock_azure_cred):
        mock_cred = mock.Mock()
        mock_sec_client = mock.Mock()
        mock_azure_cred.return_value = mock_cred
        mock_secret_client.return_value = mock_sec_client

        mock_sec_client.get_secret.return_value = mock.Mock(
            value='postgresql://airflow:airflow@host:5432/airflow'
        )

        backend = AzureKeyVaultBackend(vault_url="https://example-akv-resource-name.vault.azure.net/")
        returned_uri = backend.get_conn_uri(conn_id='hi')
        mock_secret_client.assert_called_once_with(
            credential=mock_cred, vault_url='https://example-akv-resource-name.vault.azure.net/'
        )
        assert returned_uri == 'postgresql://airflow:airflow@host:5432/airflow'