调用get in sure-sure时的空指针异常:无法在null对象上获取属性'assertionClosure'

我试图使用restured来实现RESTful API的测试,但是在尝试调用get动作时我遇到了一个空指针异常.授权是一种自定义方案,因此一旦我获得了请求的授权签名,我就将其作为标头添加到请求中:

    String auth = ...CUSTOM ALGORITHM ...;
    String pragma = ... OTHER CUSTOM HEADER ...;

    RequestSpecification requestSpec = new RequestSpecBuilder()
       .addHeader("Authorization", auth)
       .addHeader("pragma", pragma)
       .build();

    RestAssured.baseURI = "https://blahblah.staging.somewhere.net";
    RestAssured.port = 443;
    RestAssured.basePath = "/endpoint_name/somefolder/resource?status=active";
    RestAssured.urlEncodingEnabled = false;

    requestSpec.get();

这会导致以下错误:

java.lang.NullPointerException:无法在null对象上获取属性'assertionClosure'