循环中调用Karate.call触发PolyglotException问题求助

问题描述 #

在Karate测试的JS函数循环中调用karate.call时，抛出Polyglot类型错误，提示找不到匹配的重载方法，导致执行失败。

测试场景代码 #

Scenario: Test
* def userList = Java.type('aws.iamUtil.users.ListUsers')
* json userID = userList.listAwsIamUserId()
* def eSearch = read(pathConfig.featureDir.elasticSearchFeatures + 'ElasticSearch.feature@elasticSearch')
* def fun = 
"""
function(array) {
var temp = "";
for (var i = 0; i < array.length; i++) {
temp = { principalId: array[i] };
karate.call(eSearch);
}
return temp;
}
"""
* def result  = fun(userID)

执行报错信息 #

js执行失败：
01: fun(userID)
<<<<
org.graalvm.polyglot.PolyglotException: 类型错误：调用com.intuit.karate.core.ScenarioBridge@445dc8dc的call成员失败，原因：未找到匹配的重载方法（重载方法：[Method[public java.lang.Object com.intuit.karate.core.ScenarioBridge.call(boolean,java.lang.String)], Method[public java.lang.Object com.intuit.karate.core.ScenarioBridge.call(java.lang.String,org.graalvm.polyglot.Value)], Method[public java.lang.Object com.intuit.karate.core.ScenarioBridge.call(java.lang.String)], Method[public java.lang.Object com.intuit.karate.core.ScenarioBridge.call(boolean,java.lang.String,org.graalvm.polyglot.Value)]], 参数：[JavaObject[classpath:features/api/elastic_search/ElasticSearch.feature (com.intuit.karate.core.Feature)] (HostObject)])
.:anonymous(Unnamed:5)

问题原因 #

在JS函数内部调用karate.call时，无法直接传入通过read()获取的Feature对象。karate.call的重载方法仅支持接收字符串路径或字符串路径+参数对象的组合，传入Feature实例会触发类型匹配失败。

修正方案 #

方式1：直接传递Feature路径并传参 #

修改JS函数，使用Feature路径字符串调用karate.call，同时传递principalId参数：

Scenario: Test
* def userList = Java.type('aws.iamUtil.users.ListUsers')
* json userID = userList.listAwsIamUserId()
* def eSearchPath = pathConfig.featureDir.elasticSearchFeatures + 'ElasticSearch.feature@elasticSearch'
* def fun = 
"""
function(array) {
var results = [];
for (var i = 0; i < array.length; i++) {
var params = { principalId: array[i] };
var callResult = karate.call(eSearchPath, params);
results.push(callResult);
}
return results;
}
"""
* def result  = fun(userID)

方式2：使用Karate内置循环替代JS函数 #

Karate本身支持karate.forEach内置循环，无需手写JS函数，更简洁且避免类型问题：

Scenario: Test
* def userList = Java.type('aws.iamUtil.users.ListUsers')
* json userID = userList.listAwsIamUserId()
* def eSearch = read(pathConfig.featureDir.elasticSearchFeatures + 'ElasticSearch.feature@elasticSearch')
* karate.forEach(userID, function(item){
    karate.call(eSearch, { principalId: item });
})

内容的提问来源于stack exchange，提问作者Kanishk Jadhav