gpt4 book ai didi

java - 在 java 中使用 mockito 记录器

转载 作者:搜寻专家 更新时间:2023-10-31 08:25:21 27 4
gpt4 key购买 nike

我正在尝试使用 mockito 验证记录器消息。

但是,我无法运行我的 junit 类来覆盖所有代码行。

你知道原因吗?

我的代码:

    public class App {
private static final Logger LOGGER = Logger.getLogger(App.class);

public List<String> addToListIfSizeIsUnder3(final List<String> list, final String value) {
if (list == null) {
LOGGER.error("A null list was passed in");
return null;
}
if (list.size() < 3) {
list.add(value);
} else {
LOGGER.debug("The list already has {} entries"+ list.size());
}
return list;
}
}

我的 JUnit 类

import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;

import java.util.ArrayList;
import java.util.List;

import org.apache.log4j.Appender;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.spi.LoggingEvent;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.ArgumentCaptor;
import org.mockito.Captor;
import org.mockito.Mock;
import org.mockito.runners.MockitoJUnitRunner;

@RunWith(MockitoJUnitRunner.class)
public class AppTest {
private App uut;
@Mock
private Appender mockAppender;
@Captor
private ArgumentCaptor<LoggingEvent> captorLoggingEvent;

@Before
public void setup() {
uut = new App();

Logger root = Logger.getRootLogger();
root.addAppender(mockAppender);
root.setLevel(Level.INFO);
}

/**
* I want to test with over 3 elements.
*/
@Test
public void testWithOver3Element() {
List<String> myList = new ArrayList<String>();
myList.add("value 1");
myList.add("value 2");
myList.add("value 3");
myList.add("value 4");
List<String> outputList = uut.addToListIfSizeIsUnder3(myList, "some value");
Assert.assertEquals(4, outputList.size());
Assert.assertFalse(myList.contains("some value"));

try {
verify(mockAppender, times(1)).doAppend(captorLoggingEvent.capture());
} catch (AssertionError e) {
e.printStackTrace();
}

LoggingEvent loggingEvent = captorLoggingEvent.getAllValues().get(0);
Assert.assertEquals("The list already has {} entries", loggingEvent.getMessage());
Assert.assertEquals(Level.DEBUG, loggingEvent.getLevel());
}
}

错误:

Wanted but not invoked: mockAppender.doAppend(); -> at AppTest.testWithOver3Element(AppTest.java:52) Actually, there were zero interactions with this mock.

at AppTest.testWithOver3Element(AppTest.java:52) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229) at org.junit.runners.ParentRunner.run(ParentRunner.java:309) at org.mockito.internal.runners.JUnit45AndHigherRunnerImpl.run(JUnit45AndHigherRunnerImpl.java:37) at org.mockito.runners.MockitoJUnitRunner.run(MockitoJUnitRunner.java:62) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

最佳答案

您可以做几件事来改进您的代码:

  1. 切换到 slf4j。这将允许您对接口(interface)进行编码,并且不知道幕后的日志记录实现(在您的情况下是 apache log4j)。

  2. 切换到 slf4j 将允许您在传递到日志记录框架时不必连接字符串 - 示例:

    • 这个声明:LOGGER.debug("列表中已有 {} 个条目"+ list.size());
    • 可以这样写:LOGGER.debug("列表中已有{}个条目", list.size());

这具有使字符串文字中的占位符实际起作用的额外好处。

  1. 您正在尝试通过日志记录框架间接断言和捕获对对象的调用。这将是脆弱且容易出错的,因为您永远不知道日志框架内部会进行哪些调用。仅模拟您的直接依赖项。

  2. 不要测试日志语句。这不是类的完全可见的行为,它使测试变得脆弱和复杂。另外,像使用 ArrayList(即语言的一部分)那样处理日志语句可以让它们得到充分利用,并将信息输出到控制台,这可能有助于调试失败的测试。脆弱的一个例子是,如果您更改日志记录语句以添加更多信息,或者您可能向该方法添加另一个日志记录语句,则此测试可能会无缘无故地中断。至少不要断言调用的次数,因为这将非常脆弱。

综上所述,如果您必须测试与日志记录框架的交互 - 这里是您的代码的修改版本,它运行并提供相同的功能。这基本上是改进列表中的选项 #3 -

package com.spring.mockito;

import static org.mockito.Mockito.spy;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

import org.apache.log4j.Logger;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.runners.MockitoJUnitRunner;

import java.util.Arrays;
import java.util.List;

@RunWith(MockitoJUnitRunner.class)
public class AppTest {

// create a mock of the logger
@Mock
private Logger logger;

private App uut;

// Not needed - dont test something that gets called through something else
// @Captor
// private ArgumentCaptor<LoggingEvent> captorLoggingEvent;

@Before
public void setup() {
// spy the class under test so we can override the logger method to return our mock logger
uut = spy(new App());
when(uut.logger()).thenReturn(logger);

// Not needed test with the mock directly.
// Logger root = Logger.getRootLogger();
// root.addAppender(mockAppender);
// root.setLevel(Level.DEBUG);
}

/**
* I want to test with over 3 elements.
*/
@Test
public void testWithOver3Element() {
List<String> myList = Arrays.asList("value 1", "value 2", "value 3", "value 4");

List<String> outputList = uut.addToListIfSizeIsUnder3(myList, "some value");

Assert.assertEquals(4, outputList.size());
Assert.assertFalse(myList.contains("some value"));
verify(logger, times(1)).debug("The list already has {} entries4");

// not needed
// try {
// verify(mockAppender, times(1)).doAppend(captorLoggingEvent.capture());
// } catch (AssertionError e) {
// e.printStackTrace();
// }
//
// LoggingEvent loggingEvent = captorLoggingEvent.getAllValues().get(0);
// Assert.assertEquals("The list already has {} entries", loggingEvent.getMessage());
// Assert.assertEquals(Level.DEBUG, loggingEvent.getLevel());
}

public static class App {
private static final Logger LOGGER = Logger.getLogger(App.class);

public List<String> addToListIfSizeIsUnder3(final List<String> list, final String value) {
if (list == null) {
logger().error("A null list was passed in");
return null;
}
if (list.size() < 3) {
list.add(value);
} else {
// if you use slf4j this concatenation is not needed
logger().debug("The list already has {} entries" + list.size());
}
return list;
}

// make a package private method for testing purposes to allow you to inject a mock
Logger logger() {
return LOGGER;
}
}
}

您还可以查看 PowerMockito 之类的包来模拟静态 - 但只有在绝对需要时才可以。

希望这对您有所帮助。

关于java - 在 java 中使用 mockito 记录器,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/41793901/

27 4 0
Copyright 2021 - 2024 cfsdn All Rights Reserved 蜀ICP备2022000587号
广告合作:1813099741@qq.com 6ren.com