spring - 如何使用 JUnit 比较两个列表

Question

我正在尝试使用 Java 8 语法比较两个字符串数组。

List<String> days= dayPartsList.get(0).getWeekdays()
                .stream()
                .sorted(Comparator.comparing(WeekdayModel::getName))
                .map(x -> x.getName().toUpperCase())
                .collect(Collectors.toList());
List<DayOfWeek> daysofWeeks =Arrays
                .stream(DayOfWeek.values())
                .sorted(Comparator.comparing(x -> x.getDisplayName(TextStyle.FULL, Locale.CANADA)))
                .collect(Collectors.toList());

assertEquals(days,daysofWeeks);

当我运行代码时，我在控制台中收到以下错误。

java.lang.AssertionError: expected: java.util.ArrayList<[FRIDAY, MONDAY, SATURDAY, SUNDAY, THURSDAY, TUESDAY, WEDNESDAY]> but was: java.util.ArrayList<[FRIDAY, MONDAY, SATURDAY, SUNDAY, THURSDAY, TUESDAY, WEDNESDAY]>
Expected :java.util.ArrayList<[FRIDAY, MONDAY, SATURDAY, SUNDAY, THURSDAY, TUESDAY, WEDNESDAY]> 
Actual   :java.util.ArrayList<[FRIDAY, MONDAY, SATURDAY, SUNDAY, THURSDAY, TUESDAY, WEDNESDAY]>
 <Click to see difference>


    at org.junit.Assert.fail(Assert.java:88)
    at org.junit.Assert.failNotEquals(Assert.java:743)
    at org.junit.Assert.assertEquals(Assert.java:118)
    at org.junit.Assert.assertEquals(Assert.java:144)
    at com.monkey.service.intergrationTest.MenuCallTest.readGetDayPartsTest(MenuCallTest.java:93)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    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.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:233)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:87)
    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$2.evaluate(ParentRunner.java:229)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:176)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70

实际结果和预期结果看起来相同，但测试仍然失败。有人知道这里发生了什么吗？谢谢

Answer 1

首先，你的问题确实不是特定于 java 8 Stream作为这里你想比较 List由 Stream 收集s 而不是 Stream他们自己。

The both actual and expected results look like same but the test is still failing.

事实上，它们看起来具有相同的“内容”，但实际上它们并不像您的测试代码中那样，您不会断言两个 String s 相等，但您断言 a List<String>等于List<DayOfWeek> .
与测试失败相关的用户友好消息只是比较对象的文本表示。

Assert.assertEquals(Object, Object)调用equals()第一个参数的方法来确定两个对象是否相等:

public class Assert {
    ...    
    private static boolean isEquals(Object expected, Object actual) {
        return expected.equals(actual);
    }
    ...    
}

还有一个DayOfWeek对象无论是什么 toString()值很可能不等于 equals()方法String具有相同 String 的对象内容。

因此，您必须在 List 中使用相同类型的元素预期和实际的结果 assertEqual()成功。