ElasticSearch java存根解析SUM

我有一个方法

getAggregateValue

，它需要一个复合聚合（ElasticSearch）和一个键。
编写单元测试；我想模拟

var aggregation=aggregations.get（aggKey）

以便它返回给定“aggKey”的

ParsedSum

类型。我该怎么做

    private Summary mapCompositeAggregationToFieldSummary(CompositeAggregation.Bucket bucket) {

        var field1 = getAggregateValue(bucket.getAggregations(), "field1");
   }

    private Long getAggregateValue(Aggregations aggregations, String aggKey) {
        var aggregation = aggregations.get(aggKey);
        if (aggregation == null) {
            return 0L;
        }
        return (long)(((ParsedSum)(aggregation)).getValue());
    }