testing - 如何测试 Apache HttpClient RequestConfig 值是否设置正确？没有公共(public) setter/getter 存在

Question

我有这个类来配置一个 HttpClient 实例:

package com.company.fraud.preauth.service.feignaccertifyclient;

    import com.company.fraud.preauth.config.ProviderClientConfig;
    import lombok.RequiredArgsConstructor;
    import lombok.extern.slf4j.Slf4j;
    import org.apache.http.client.HttpClient;
    import org.apache.http.client.config.RequestConfig;
    import org.apache.http.conn.ssl.TrustSelfSignedStrategy;
    import org.apache.http.impl.client.HttpClientBuilder;
    import org.apache.http.ssl.SSLContextBuilder;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;

    import java.security.KeyManagementException;
    import java.security.KeyStoreException;
    import java.security.NoSuchAlgorithmException;


    @Slf4j
    @Configuration
    @RequiredArgsConstructor
    public class FeignClientConfig {

        private final ProviderClientConfig providerClientConfig;

        public HttpClient buildHttpClient() throws NoSuchAlgorithmException, KeyStoreException, KeyManagementException {
            RequestConfig.Builder requestBuilder = RequestConfig.custom();
            requestBuilder.setConnectTimeout(providerClientConfig.getConnectionTimeout());
            requestBuilder.setConnectionRequestTimeout(providerClientConfig.getConnectionRequestTimeout());
            requestBuilder.setSocketTimeout(providerClientConfig.getSocketTimeout());
            SSLContextBuilder builder = new SSLContextBuilder();
            builder.loadTrustMaterial(null, new TrustSelfSignedStrategy());

            return HttpClientBuilder.create()
                    .setMaxConnPerRoute(providerClientConfig.getMaxConnectionNumber())
                    .setDefaultRequestConfig(requestBuilder.build())
                    .setSSLContext(builder.loadTrustMaterial(null, new TrustSelfSignedStrategy()).build())
                    .build();
        }
    }

如何对此类进行单元测试，以查看结果 HttpClient 是否正确设置了这些值？

从 httpClient 我无法访问它的 RequestConfig。

我知道这两个帖子:

How do I test a private function or a class that has private methods, fields or inner classes?(这个问题的投票数表明它是测试中一个并发且有争议的话题，我的情况可以提供一个例子，说明为什么我们应该在测试中查看实例的内部状态，尽管它是私有(private)的)

Unit test timeouts in Apache HttpClient(它显示了一种在代码中添加拦截器以检查配置值的方法，但我不喜欢它，因为我想将测试与功能代码分开)

有什么办法吗？我明白这个类应该被测试，对吧？您不能盲目地相信它会起作用；并检查它“notNull”对我来说似乎很脆弱。

---

此链接可能会为我指明正确的方向:

https://dzone.com/articles/testing-objects-internal-state

它使用 PowerMock.Whitebox 检查实例的内部状态。

Answer 1

所以我查看了 PowerMock.Whitebox 源代码，结果发现内部使用了反射。而且，由于据说 PowerMock 与 JUnit 5 不兼容(直到现在)，而且我不想添加另一个仅用于测试的依赖项，所以我将使用反射进行测试。

package com.company.fraud.preauth.service.feignaccertifyclient;

import com.company.fraud.preauth.config.PreAuthConfiguration;
import com.company.fraud.preauth.config.ProviderClientConfig;
import com.company.fraud.preauth.config.StopConfiguration;
import org.apache.http.client.HttpClient;
import org.apache.http.client.config.RequestConfig;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.Mock;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit.jupiter.SpringExtension;

import java.lang.reflect.Field;

import static org.hamcrest.CoreMatchers.equalTo;
import static org.junit.Assert.assertThat;
import static org.mockito.Mockito.when;

@ExtendWith(SpringExtension.class)
@SpringBootTest(classes = {
        PreAuthConfiguration.class,
        StopConfiguration.class,
})
public class FeignClientConfigTest {

    @Mock
    private ProviderClientConfig providerClientConfig;

    @Test
    @DisplayName("should return HttpClient with defaultConfig field filled with values in providerClientConfig")
    public void shouldReturnHttpClientWithConfiguredValues() throws Exception {
        // given
        when(providerClientConfig.getConnectionRequestTimeout()).thenReturn(30000);
        when(providerClientConfig.getConnectionTimeout()).thenReturn(30);
        when(providerClientConfig.getMaxConnNumPerRoute()).thenReturn(20);
        when(providerClientConfig.getSocketTimeout()).thenReturn(10);
        FeignClientConfig feignClientConfig = new FeignClientConfig(providerClientConfig);

        // when
        HttpClient httpClient = feignClientConfig.buildHttpClient();

        // then
        // I want to test internal state of built HttpClient and this should be checked
        // I tried to use PowerMock.Whitebox, but then I found it uses reflection internally
        // I don't want to introduce another dependency, and PowerMock is said not to be compatible with JUnit 5, so..
        Field requestConfigField = httpClient.getClass().getDeclaredField("defaultConfig");
        requestConfigField.setAccessible(true);
        RequestConfig requestConfig = (RequestConfig)requestConfigField.get(httpClient);
        assertThat(requestConfig.getConnectionRequestTimeout(), equalTo(30000));
        assertThat(requestConfig.getConnectTimeout(), equalTo(30));
        assertThat(requestConfig.getSocketTimeout(), equalTo(10));
    }

}

此外，我回答了 OP 中关于何时测试类中私有(private)成员的第一个问题 here