Hello folks, I have been trying to write some tests for client tools. And, always this error occurs

java.lang.NullPointerException: Cannot invoke "org.apache.pulsar.client.admin.Tenants.createTenant(String, org.apache.pulsar.common.policies.data.TenantInfo)" because the return value of "org.apache.pulsar.client.admin.PulsarAdmin.tenants()" is null