JUnit 5 @RepeatedTest注解详解

这段文本主要描述了JUnit框架中的@RepeatedTest注解，它用于编写可重复运行的测试模板。@RepeatedTest注解可以配置重复频率作为参数。

1.@RepeatedTest注解

@RepeatedTest注解用于标记需要重复特定次数并且可配置显示名称的测试方法。

如果想要用不同的参数重复测试，建议使用@ParameterizedTest注解。

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1.1 语法

要创建可重复的测试，给测试方法添加@RepeatedTest注解。

在给定的示例中，测试方法使用了@RepeatedTest(5)注解，意味着该测试将执行五次。

@DisplayName("Add operation test")
@RepeatedTest(5)
void addNumber(TestInfo testInfo) {
	Calculator calculator = new Calculator();
	Assertions.assertEquals(2, calculator.add(1, 1), "1 + 1 should equal 2");
}

1.2 生命周期方法

请注意，每次重复测试的行为都类似于常规测试的执行，并完全支持相同的生命周期回调和扩展。这意味着@BeforeEach和@AfterEach注解的生命周期方法将针对每次测试调用进行调用。

@RunWith(JUnitPlatform.class)
public class RepeatedTestExample {

	@BeforeAll
	public static void init(){
		System.out.println("Before All init() method called");
	}

	@BeforeEach
	public void initEach(){
		System.out.println("Before Each initEach() method called");
	}

	@DisplayName("Add operation test")
	@RepeatedTest(5)
	void addNumber(TestInfo testInfo, RepetitionInfo repetitionInfo)
	{
		System.out.println("Running addNumber test -> " + repetitionInfo.getCurrentRepetition());
		Assertions.assertEquals(2, Calculator.add(1, 1), "1 + 1 should equal 2");
	}

	@AfterEach
	public void cleanUpEach(){
		System.out.println("After Each cleanUpEach() method called");
	}

	@AfterAll
	public static void cleanUp(){
		System.out.println("After All cleanUp() method called");
	}
}

上述测试的输出：

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Before All init() method called
Before Each initEach() method called
After Each cleanUpEach() method called
Before Each initEach() method called
Running addNumber test -> 1
After Each cleanUpEach() method called
Before Each initEach() method called
Running addNumber test -> 2
After Each cleanUpEach() method called
Before Each initEach() method called
Running addNumber test -> 3
After Each cleanUpEach() method called
Before Each initEach() method called
Running addNumber test -> 4
After Each cleanUpEach() method called
Before Each initEach() method called
Running addNumber test -> 5
After Each cleanUpEach() method called
After All cleanUp() method called

2.自定义显示名称

除了指定重复次数外，还可以为每个重复提供自定义显示名称，这个自定义显示名称可以是{static text + dynamic placeholders}的组合。

目前，支持三种占位符：

• {displayName}：@RepeatedTest方法的显示名称。
• {currentRepetition}：当前重复计数。
• {totalRepetitions}：总的重复次数。

public class JUnit5AnnotationsExample
{
	@DisplayName("Add operation test")
	@RepeatedTest(value = 5, name = "{displayName} - repetition {currentRepetition} of {totalRepetitions}")
	void addNumber(TestInfo testInfo) {
		Assertions.assertEquals(2, Calculator.add(1, 1), "1 + 1 should equal 2");
	}
}

运行上述测试将输出以下内容：我们可以使用两种预定义格式之一，即LONG_DISPLAY_NAME和SHORT_DISPLAY_NAME。如果未指定，则默认使用后者。

• RepeatedTest.LONG_DISPLAY_NAME – {displayName} :: repetition {currentRepetition} of {totalRepetitions}
• RepeatedTest.SHORT_DISPLAY_NAME – repetition {currentRepetition} of {totalRepetitions}

@DisplayName("Add operation test")
@RepeatedTest(value = 5, name = RepeatedTest.LONG_DISPLAY_NAME)
void addNumber(TestInfo testInfo) {
	Assertions.assertEquals(2, Calculator .add(1, 1), "1 + 1 should equal 2");
}

3.RepetitionInfo接口

RepetitionInfo用于获取当前重复测试在@RepeatedTest注解或生命周期方法（如@BeforeEach和@AfterEach）中的重复信息。

public class JUnit5AnnotationsExample {
	@BeforeEach
	public void initEach(RepetitionInfo info){
		int currentRepetition = info.getCurrentRepetition();
        int totalRepetitions = info.getTotalRepetitions();
        //Use information as needed
	}
	@DisplayName("Add operation test")
	@RepeatedTest(value = 5, name="{displayName} :: repetition {currentRepetition} of {totalRepetitions}")
	void addNumber(TestInfo testInfo) {
		Calculator calculator = new Calculator();
		Assertions.assertEquals(2, calculator.add(1, 1), "1 + 1 should equal 2");
	}
	@AfterEach
	public void cleanUpEach(RepetitionInfo info){
		int currentRepetition = info.getCurrentRepetition();
        int totalRepetitions = info.getTotalRepetitions();
        //Use information as needed
	}
}