public ProvisioningTester build() {
            return new ProvisioningTester(Optional.ofNullable(curator).orElseGet(MockCurator::new),
                                          new NodeFlavors(Optional.ofNullable(flavorsConfig).orElseGet(ProvisioningTester::createConfig)),
                                          resourcesCalculator,
                                          Optional.ofNullable(zone).orElseGet(() -> new Zone(Cloud.builder().snapshotPrivateKeySecretName("snapshot/sealingPrivateKey").build(),
                                                                                             SystemName.defaultSystem(), Environment.defaultEnvironment(),
                                                                                             RegionName.defaultName())),
                                          Optional.ofNullable(nameResolver).orElseGet(() -> new MockNameResolver().mockAnyLookup()),
                                          defaultImage,
                                          Optional.ofNullable(orchestrator).orElseGet(() -> new OrchestratorMock(clock)),
                                          hostProvisioner,
                                          new LoadBalancerServiceMock(),
                                          Optional.ofNullable(flagSource).orElseGet(this::defaultFlagSource),
                                          spareCount,
                                          clock,
                                          Optional.ofNullable(secretStore).orElseGet(this::defaultSecretStore));
        }
Returns the hosts from the input list which are not retired
node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/ProvisioningTester.java