概述
在现代软件开发中，API和单元测试自动化是确保代码质量的关键环节。Java凭借其强大的生态系统、丰富的测试框架和工具链，在测试自动化领域具有显著优势。
Java测试生态系统的优势
1. 丰富的测试框架
- JUnit 5 - 现代测试框架
- TestNG - 功能丰富的测试框架
- Mockito - 强大的Mocking框架
- RestAssured - API测试专用库
- WireMock - HTTP Mock服务器
2. 构建工具集成
- Maven - 依赖管理和测试生命周期
- Gradle - 灵活的构建脚本
- Surefire/Failsafe - 测试执行插件
3. 持续集成支持
- Jenkins集成
- GitLab CI管道
- GitHub Actions工作流
JUnit 5 单元测试自动化实践
JUnit 5 是 Java 生态中最流行的单元测试框架，由三个主要模块组成：
- JUnit Platform - 测试执行的基础平台
- JUnit Jupiter - 新的编程模型和扩展模型
- JUnit Vintage - 兼容 JUnit 3/4 的测试引擎
2. 环境配置
Maven 依赖
<properties><junit.jupiter.version>5.14.1</junit.jupiter.version><junit.platform.version>1.14.1</junit.platform.version>
</properties><!--region Junit5 --><dependency><groupId>org.junit.jupiter</groupId><artifactId>junit-jupiter</artifactId><version>${junit.jupiter.version}</version></dependency><!-- JUnit 5 API（编写测试用例） --><dependency><groupId>org.junit.jupiter</groupId><artifactId>junit-jupiter-api</artifactId><version>${junit.jupiter.version}</version></dependency><!-- JUnit 5 执行引擎（运行测试用例，必须，否则套件里的测试无法执行） --><dependency><groupId>org.junit.jupiter</groupId><artifactId>junit-jupiter-engine</artifactId><version>${junit.jupiter.version}</version></dependency><!-- JUnit 5 参数化测试（参数解析） --><dependency><groupId>org.junit.jupiter</groupId><artifactId>junit-jupiter-params</artifactId><version>${junit.jupiter.version}</version></dependency><dependency><groupId>org.junit.platform</groupId><artifactId>junit-platform-commons</artifactId><version>${junit.platform.version}</version></dependency><dependency><groupId>org.junit.platform</groupId><artifactId>junit-platform-console</artifactId><version>${junit.platform.version}</version></dependency><dependency><groupId>org.junit.platform</groupId><artifactId>junit-platform-engine</artifactId><version>${junit.platform.version}</version></dependency><!-- 测试调度中枢（自定义测试执行逻辑）--><dependency><groupId>org.junit.platform</groupId><artifactId>junit-platform-launcher</artifactId><version>${junit.platform.version}</version></dependency><dependency><groupId>org.junit.platform</groupId><artifactId>junit-platform-reporting</artifactId><version>${junit.platform.version}</version></dependency><dependency><groupId>org.junit.platform</groupId><artifactId>junit-platform-runner</artifactId><version>${junit.platform.version}</version></dependency><!-- 套件执行（运行套件）--><dependency><groupId>org.junit.platform</groupId><artifactId>junit-platform-suite</artifactId><version>${junit.platform.version}</version></dependency><!-- 套件 API（定义套件） --><dependency><groupId>org.junit.platform</groupId><artifactId>junit-platform-suite-api</artifactId><version>${junit.platform.version}</version></dependency><!-- 套件公共资源 --><dependency><groupId>org.junit.platform</groupId><artifactId>junit-platform-suite-commons</artifactId><version>${junit.platform.version}</version></dependency><dependency><groupId>org.junit.platform</groupId><artifactId>junit-platform-suite-engine</artifactId><version>${junit.platform.version}</version></dependency><!-- Hamcrest 核心匹配器 --><dependency><groupId>org.hamcrest</groupId><artifactId>hamcrest</artifactId><version>2.2</version></dependency><!--endregion -->
1. 基本注解
核心注解
import org.junit.jupiter.api.*;class BasicAnnotationsTest {@BeforeAllstatic void setUpClass() {System.out.println("在所有测试方法之前执行一次");}@BeforeEachvoid setUp() {System.out.println("在每个测试方法之前执行");}@Testvoid testMethod() {System.out.println("测试方法");}@AfterEachvoid tearDown() {System.out.println("在每个测试方法之后执行");}@AfterAllstatic void tearDownClass() {System.out.println("在所有测试方法之后执行一次");}
}
测试生命周期注解
import org.junit.jupiter.api.*;@TestInstance(TestInstance.Lifecycle.PER_CLASS)
class LifecycleTest {private int counter = 0;@BeforeAllvoid classSetup() {// 由于使用 PER_CLASS，@BeforeAll 可以是实例方法System.out.println("类初始化");}@Testvoid test1() {counter++;System.out.println("Counter: " + counter);}@Testvoid test2() {counter++;System.out.println("Counter: " + counter);}
}
2. 断言
基本断言
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;class AssertionsTest {@Testvoid standardAssertions() {assertEquals(2, 1 + 1);assertEquals(4, 2 * 2, "可选的失败消息");assertTrue('a' < 'b', () -> "断言消息可以延迟计算");}@Testvoid groupedAssertions() {// 所有断言都会执行，所有失败会一起报告assertAll("person",() -> assertEquals("John", "John"),() -> assertEquals("Doe", "Doe"));}@Testvoid exceptionTesting() {Exception exception = assertThrows(ArithmeticException.class, () -> {int result = 1 / 0;});assertEquals("/ by zero", exception.getMessage());}@Testvoid timeoutTest() {assertTimeoutPreemptively(Duration.ofSeconds(2), () -> {// 如果超时会被立即中断Thread.sleep(1000);});}
}
Hamcrest 断言
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.*;class HamcrestTest {@Testvoid hamcrestAssertions() {assertThat("test", is("test"));assertThat(Arrays.asList(1, 2, 3), hasSize(3));assertThat("hello world", containsString("world"));assertThat(100.0, closeTo(99.0, 2.0));}
}
3. 假设
import org.junit.jupiter.api.Assumptions;
import org.junit.jupiter.api.Test;class AssumptionsTest {@Testvoid testOnlyOnCiServer() {Assumptions.assumeTrue("CI".equals(System.getenv("ENV")));// 只有在 CI 环境下才会执行的测试}@Testvoid testOnlyOnDeveloperWorkstation() {Assumptions.assumeTrue("DEV".equals(System.getenv("ENV")),() -> "跳过：不在开发环境");}@Testvoid testInAllEnvironments() {Assumptions.assumingThat("CI".equals(System.getenv("ENV")),() -> {// 只有在 CI 环境下才会执行的断言assertEquals(2, 1 + 1);});// 在所有环境下都会执行的断言assertTrue(true);}
}
4. 显示名称和嵌套测试
显示名称
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;@DisplayName("计算器测试")
class DisplayNameTest {@Test@DisplayName("🔢 加法测试")void testAddition() {assertEquals(2, 1 + 1);}@Test@DisplayName("😱 除法测试 - 除以零")void testDivisionByZero() {assertThrows(ArithmeticException.class, () -> {int result = 1 / 0;});}
}
嵌套测试
import org.junit.jupiter.api.Nested;
import org.junit.jupiter.api.Test;class StackTest {Stack<Object> stack;@Testvoid isInstantiatedWithNew() {new Stack<>();}@Nestedclass WhenNew {@BeforeEachvoid createNewStack() {stack = new Stack<>();}@Testvoid isEmpty() {assertTrue(stack.isEmpty());}@Nestedclass AfterPushing {String anElement = "an element";@BeforeEachvoid pushAnElement() {stack.push(anElement);}@Testvoid isNotEmpty() {assertFalse(stack.isEmpty());}@Testvoid returnsElementWhenPopped() {assertEquals(anElement, stack.pop());}}}
}
5. 参数化测试
基本参数化测试
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.*;class ParameterizedTests {@ParameterizedTest@ValueSource(strings = {"racecar", "radar", "able was I ere I saw elba"})void palindromes(String candidate) {assertTrue(StringUtils.isPalindrome(candidate));}@ParameterizedTest@CsvSource({"apple, 1","banana, 2","'lemon, lime', 3"})void testWithCsvSource(String fruit, int rank) {assertNotNull(fruit);assertTrue(rank > 0);}@ParameterizedTest@CsvFileSource(resources = "/test-data.csv")void testWithCsvFileSource(String name, int age) {assertNotNull(name);assertTrue(age >= 0);}@ParameterizedTest@MethodSource("stringProvider")void testWithMethodSource(String argument) {assertNotNull(argument);}static Stream<String> stringProvider() {return Stream.of("apple", "banana");}@ParameterizedTest@ArgumentsSource(MyArgumentsProvider.class)void testWithArgumentsSource(String argument) {assertNotNull(argument);}static class MyArgumentsProvider implements ArgumentsProvider {@Overridepublic Stream<? extends Arguments> provideArguments(ExtensionContext context) {return Stream.of("apple", "banana").map(Arguments::of);}}
}
6. 动态测试
import org.junit.jupiter.api.DynamicTest;
import org.junit.jupiter.api.TestFactory;import java.util.stream.Stream;class DynamicTests {@TestFactoryStream<DynamicTest> dynamicTestsFromStream() {return Stream.of("A", "B", "C").map(str -> DynamicTest.dynamicTest("Test " + str, () -> assertTrue(str.length() == 1)));}@TestFactoryStream<DynamicTest> generateRandomNumberOfTests() {// 生成随机数量的测试Iterator<String> inputGenerator = Arrays.asList("A", "B", "C", "D").iterator();return Stream.generate(() -> {if (inputGenerator.hasNext()) {String input = inputGenerator.next();return DynamicTest.dynamicTest("Dynamic Test for " + input,() -> assertNotNull(input));}return null;}).takeWhile(Objects::nonNull);}
}
7. 测试执行顺序
import org.junit.jupiter.api.MethodOrderer;
import org.junit.jupiter.api.Order;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.TestMethodOrder;@TestMethodOrder(MethodOrderer.OrderAnnotation.class)
class OrderedTests {@Test@Order(3)void testC() {System.out.println("Test C");}@Test@Order(1)void testA() {System.out.println("Test A");}@Test@Order(2)void testB() {System.out.println("Test B");}
}@TestMethodOrder(MethodOrderer.Random.class)
class RandomOrderTests {// 测试方法会以随机顺序执行
}
8. 扩展模型
自定义扩展
import org.junit.jupiter.api.extension.*;class LoggingExtension implements BeforeEachCallback, AfterEachCallback {@Overridepublic void beforeEach(ExtensionContext context) {System.out.println("开始测试: " + context.getDisplayName());}@Overridepublic void afterEach(ExtensionContext context) {System.out.println("结束测试: " + context.getDisplayName());}
}@ExtendWith(LoggingExtension.class)
class ExtendedTest {@Testvoid testWithExtension() {// 这个测试会自动应用 LoggingExtension}
}
参数解析器
import org.junit.jupiter.api.extension.ParameterResolver;class RandomNumberParameterResolver implements ParameterResolver {@Overridepublic boolean supportsParameter(ParameterContext parameterContext, ExtensionContext extensionContext) {return parameterContext.getParameter().getType() == int.class;}@Overridepublic Object resolveParameter(ParameterContext parameterContext, ExtensionContext extensionContext) {return new Random().nextInt(100);}
}@ExtendWith(RandomNumberParameterResolver.class)
class ParameterResolverTest {@Testvoid testWithInjectedParameter(@Random int number) {assertTrue(number >= 0 && number < 100);}
}
9. 条件测试
import org.junit.jupiter.api.condition.*;class ConditionalExecutionTest {@Test@EnabledOnOs(OS.WINDOWS)void onlyOnWindows() {// 只在 Windows 上运行}@Test@DisabledOnOs(OS.MAC)void notOnMac() {// 不在 Mac 上运行}@Test@EnabledOnJre(JRE.JAVA_11)void onlyOnJava11() {// 只在 Java 11 上运行}@Test@EnabledIfSystemProperty(named = "os.arch", matches = ".*64.*")void onlyOn64BitArchitecture() {// 只在 64 位架构上运行}@Test@EnabledIfEnvironmentVariable(named = "ENV", matches = "ci")void onlyOnCiServer() {// 只在 CI 服务器上运行}@Test@EnabledIf("customCondition")void basedOnCustomCondition() {// 基于自定义条件运行}boolean customCondition() {return true;}
}
10. 测试接口和默认方法
interface TestLifecycleLogger {@BeforeAllstatic void beforeAllTests() {System.out.println("Before all tests");}@AfterAllstatic void afterAllTests() {System.out.println("After all tests");}@BeforeEachdefault void beforeEachTest(TestInfo testInfo) {System.out.println("Before test: " + testInfo.getDisplayName());}
}interface TimeExecutionLogger {@Testdefault void testTimeExecution() {long start = System.currentTimeMillis();// 测试逻辑long duration = System.currentTimeMillis() - start;System.out.println("Test executed in: " + duration + "ms");}
}class InterfaceTest implements TestLifecycleLogger, TimeExecutionLogger {// 自动继承接口中的测试方法
}
11. 测试模板
import org.junit.jupiter.api.TestTemplate;
import org.junit.jupiter.api.extension.ExtendWith;class TestTemplateTest {@TestTemplate@ExtendWith(MyTestTemplateInvocationContextProvider.class)void testTemplate(String parameter) {assertNotNull(parameter);}
}class MyTestTemplateInvocationContextProvider implements TestTemplateInvocationContextProvider {@Overridepublic boolean supportsTestTemplate(ExtensionContext context) {return true;}@Overridepublic Stream<TestTemplateInvocationContext> provideTestTemplateInvocationContexts(ExtensionContext context) {return Stream.of("foo", "bar").map(this::invocationContext);}private TestTemplateInvocationContext invocationContext(String parameter) {return new TestTemplateInvocationContext() {@Overridepublic String getDisplayName(int invocationIndex) {return "Parameter: " + parameter;}@Overridepublic List<Extension> getAdditionalExtensions() {return Collections.singletonList(new ParameterResolver() {@Overridepublic boolean supportsParameter(ParameterContext parameterContext, ExtensionContext extensionContext) {return parameterContext.getParameter().getType() == String.class;}@Overridepublic Object resolveParameter(ParameterContext parameterContext, ExtensionContext extensionContext) {return parameter;}});}};}
}
12. 测试套件
import org.junit.platform.suite.api.*;@Suite
@SelectPackages("com.example.tests")
@IncludeClassNamePatterns(".*Test")
@ExcludeTags("slow")
@IncludeEngines("junit-jupiter")
public class TestSuite {// 运行指定包中的所有测试，排除标记为 slow 的测试
}
这里基本已经涵盖了 JUnit 5 的主要功能。根据具体需求，我们可以选择适合的功能来编写高效、可维护的测试代码。
