public static PemAuthIdentity clusterOperator(Secret secret) {
        return new PemAuthIdentity(secret, "cluster-operator");
    }
@Test
    public void testMissingSecret() {
        Exception e = assertThrows(NullPointerException.class, () -> PemAuthIdentity.clusterOperator(null));
        assertThat(e.getMessage(), is("Cannot extract auth identity from null secret."));
    }