private static BucketspacesConfig getBucketspacesConfig(ContentCluster cluster) {
        BucketspacesConfig.Builder builder = new BucketspacesConfig.Builder();
        cluster.getConfig(builder);
        return new BucketspacesConfig(builder);
    }
Unit tests for content search cluster.

@author geirst
config-model/src/test/java/com/yahoo/vespa/model/content/ContentSchemaClusterTest.java