如何模拟 Elasticsearch Java 客户端？

Question

您知道如何适当地模拟 Elasticsearch Java 客户端吗？ 目前在 Java 中模拟以下请求：

SearchResponse response = client.prepareSearch(index)
                .setTypes(type)
                .setFrom(0).setSize(MAX_SIZE)
                .execute()
                .actionGet();
SearchHit[] hits = response.getHits().getHits();

我必须嘲笑：

• client.prepareSearch
• 搜索请求构建器：
  • builder.execute
  • builder.setSize
  • builder.setFrom
  • builder.setTypes
• 搜索响应：
  • action.actionGet
• 搜索响应：
  • response.getHits
  • searchHits.getHits

所以我的测试看起来像：

SearchHit[] hits = ..........;

SearchHits searchHits = mock(SearchHits.class);
when(searchHits.getHits()).thenReturn(hits);

SearchResponse response = mock(SearchResponse.class);
when(response.getHits()).thenReturn(searchHits);

ListenableActionFuture<SearchResponse> action = mock(ListenableActionFuture.class);
when(action.actionGet()).thenReturn(response);

SearchRequestBuilder builder = mock(SearchRequestBuilder.class);
when(builder.setTypes(anyString())).thenReturn(builder);
when(builder.setFrom(anyInt())).thenReturn(builder);
when(builder.setSize(anyInt())).thenReturn(builder);
when(builder.execute()).thenReturn(action);

when(client.prepareSearch(index)).thenReturn(builder);

丑...所以我想知道是否有更“优雅的方式”来模拟这段代码。

谢谢

Answer 1

我在模拟构建器时遇到了类似的问题，所以我想我会尝试看看是否有更好的方法。

正如 Spoon 先生所说，如果您一开始就可以避免这样做可能会更好，因为它不是您的代码，并且可以被假定为“正常工作”，但我想无论如何我都会试一试。

通过在 Mockito 中使用“默认答案”，我想出了一种（可能是粗略的）方法。 我还在决定我是否喜欢它。

这是我的建设者...

public class MyBuilder {

    private StringBuilder my;

    public MyBuilder() {
        my = new StringBuilder();
    }

    public MyBuilder name(String name) {
        my.append("[name=").append(name).append("]");
        return this;
    }

    public MyBuilder age(String age) {
        my.append("[age=").append(age).append("]");
        return this;
    }

    public String create() {
        return my.toString();
    }
}

（很基本的吧？）

我的测试看起来像这样......

// Create a "BuilderMocker" (any better name suggestions welcome!) 
BuilderMocker<MyBuilder> mocker = BuilderMocker.forClass(MyBuilder.class);
// Get the actual mock builder
MyBuilder builder = mocker.build();

// expect this chain of method calls...
mocker.expect().name("[NAME]").age("[AGE]");

// expect this end-of-chain method call...
Mockito.when(builder.create()).thenReturn("[ARGH!]");

现在，如果我执行以下操作...

System.out.println(builder.name("[NAME]").age("[AGE]").create());

...我希望输出“[ARGH！]”。

如果我更改了最后一行...

System.out.println(builder.name("[NOT THIS NAME]").age("[AGE]").create());

...然后我希望它会因 NullPointerException 而中断。

这是实际的“BuilderMocker”...

import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;
import static org.mockito.Mockito.withSettings;

import org.mockito.invocation.InvocationOnMock;
import org.mockito.stubbing.Answer;

public class BuilderMocker<T> {

    private Class<T> clazz;
    private T recorder;
    private T mock;

    // Create a BuilderMocker for the class
    public static <T> BuilderMocker<T> forClass(Class<T> clazz) {
        return new BuilderMocker<T>(clazz);
    }

    private BuilderMocker(Class<T> clazz) {
        this.clazz = clazz;
        this.mock = mock(clazz);
        createRecorder();
    }

    // Sets up the "recorder"
    private void createRecorder() {
        recorder = mock(clazz, withSettings().defaultAnswer(new Answer<Object>() {

            @Override
            public Object answer(InvocationOnMock invocation) throws Throwable {
                // If it is a chained method...
                if (invocation.getMethod().getReturnType().equals(clazz)) {
                    // Set expectation on the "real" mock...
                    when(invocation.getMethod().invoke(mock, invocation.getArguments())).thenReturn(mock);
                    return recorder;
                }
                return null;
            }

        }));
    }

    // Use this to "record" the expected method chain
    public T expect() {
        return recorder;
    }

    // Use this to get the "real" mock...
    public T build() {
        return mock;
    }
}

不确定在 Mockito 中是否有“内置”的方式来做到这一点，但这似乎有效。