在Spring引入Java Config机制之后,我们会越来越多的使用@Configuration来注册Bean,并且Spring Boot更广泛地使用了这一机制,其提供的大量Auto Configuration大大简化了配置工作。那么问题来了,如何确保@Configuration和Auto Configuration按照预期运行呢,是否正确地注册了Bean呢?本章举例测试@Configuration和Auto Configuration的方法(因为Auto Configuration也是@Configuration,所以测试方法是一样的)。
例子1:测试@Configuration
我们先写一个简单的@Configuration:
@Configuration public class FooConfiguration { @Bean public Foo foo() { return new Foo(); } } |
然后看FooConfiguration是否能够正确地注册Bean:
public class FooConfigurationTest { private AnnotationConfigApplicationContext context; @BeforeMethod public void init() { context = new AnnotationConfigApplicationContext(); } @AfterMethod(alwaysRun = true) public void reset() { context.close(); } @Test public void testFooCreation() { context.register(FooConfiguration.class); context.refresh(); assertNotNull(context.getBean(Foo.class)); } } |
注意上面代码中关于Context的代码:
1.首先,我们构造一个Context
2.然后,注册FooConfiguration
3.然后,refresh Context
4.最后,在测试方法结尾close Context
如果你看Spring Boot中关于@Configuration测试的源代码会发现和上面的代码有点不一样:
public class DataSourceAutoConfigurationTests { private final AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(); @Before public void init() { EmbeddedDatabaseConnection.override = null; EnvironmentTestUtils.addEnvironment(this.context, "spring.datasource.initialize:false", "spring.datasource.url:jdbc:hsqldb:mem:testdb-" + new Random().nextInt()); } @After public void restore() { EmbeddedDatabaseConnection.override = null; this.context.close(); } |
例子2:测试@Conditional
Spring Framework提供了一种可以条件控制@Configuration的机制,即只在满足某条件的情况下才会导入@Configuration,这就是 @Conditional 。
下面我们来对@Conditional做一些测试,首先我们自定义一个 Condition FooConfiguration :
@Configuration public class FooConfiguration { @Bean @Conditional(FooCondition.class) public Foo foo() { return new Foo(); } public static class FooCondition implements Condition { @Override public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) { if (context.getEnvironment() != null) { Boolean property = context.getEnvironment().getProperty("foo.create", Boolean.class); return Boolean.TRUE.equals(property); } return false; } } } |
该Condition判断 Environment 中是否有 foo.create=true 。
如果我们要测试这个Condition,那么就必须往Environment里添加相关property才可以,在这里我们测试了三种情况:
1.没有配置 foo.create=true
2.配置 foo.create=true
3.配置 foo.create=false
FooConfigurationTest :
public class FooConfigurationTest { private AnnotationConfigApplicationContext context; @BeforeMethod public void init() { context = new AnnotationConfigApplicationContext(); } @AfterMethod(alwaysRun = true) public void reset() { context.close(); } @Test(expectedExceptions = NoSuchBeanDefinitionException.class) public void testFooCreatePropertyNull() { context.register(FooConfiguration.class); context.refresh(); context.getBean(Foo.class); } @Test public void testFooCreatePropertyTrue() { context.getEnvironment().getPropertySources().addLast( new MapPropertySource("test", Collections.singletonMap("foo.create", "true")) ); context.register(FooConfiguration.class); context.refresh(); assertNotNull(context.getBean(Foo.class)); } @Test(expectedExceptions = NoSuchBeanDefinitionException.class) public void testFooCreatePropertyFalse() { context.getEnvironment().getPropertySources().addLast( new MapPropertySource("test", Collections.singletonMap("foo.create", "false")) ); context.register(FooConfiguration.class); context.refresh(); assertNotNull(context.getBean(Foo.class)); } } |
注意我们用以下方法来给Environment添加property:
context.getEnvironment().getPropertySources().addLast( new MapPropertySource("test", Collections.singletonMap("foo.create", "true")) ); |
所以针对@Conditional和其对应的Condition的测试的根本就是给它不一样的条件,判断其行为是否正确,在这个例子里我们的Condition比较简单,只是判断是否存在某个property,如果复杂Condition的话,测试思路也是一样的。
例子3:测试@ConditionalOnProperty
Spring framework只提供了@Conditional,Spring boot对这个机制做了扩展,提供了更为丰富的 @ConditionalOn* ,这里我们以 @ConditionalOnProperty 举例说明。
先看 FooConfiguration :
@Configuration public class FooConfiguration { @Bean @ConditionalOnProperty(prefix = "foo", name = "create", havingValue = "true") public Foo foo() { return new Foo(); } } |
FooConfigurationTest :
public class FooConfigurationTest { private AnnotationConfigApplicationContext context; @BeforeMethod public void init() { context = new AnnotationConfigApplicationContext(); } @AfterMethod(alwaysRun = true) public void reset() { context.close(); } @Test(expectedExceptions = NoSuchBeanDefinitionException.class) public void testFooCreatePropertyNull() { context.register(FooConfiguration.class); context.refresh(); context.getBean(Foo.class); } @Test public void testFooCreatePropertyTrue() { EnvironmentTestUtils.addEnvironment(context, "foo.create=true"); context.register(FooConfiguration.class); context.refresh(); assertNotNull(context.getBean(Foo.class)); } @Test(expectedExceptions = NoSuchBeanDefinitionException.class) public void testFooCreatePropertyFalse() { EnvironmentTestUtils.addEnvironment(context, "foo.create=false"); context.register(FooConfiguration.class); context.refresh(); assertNotNull(context.getBean(Foo.class)); } } |
这段测试代码和例子2的逻辑差不多,只不过例子2里使用了我们自己写的Condition,这里使用了Spring Boot提供的@ConditionalOnProperty。
并且利用了Spring Boot提供的[EnvironmentTestUtils][javadoc-spring-boot-EnvironmentTestUtils]简化了给Environment添加property的工作:
EnvironmentTestUtils.addEnvironment(context, "foo.create=false");
例子4:测试Configuration Properties
Spring Boot还提供了类型安全的 Configuration Properties ,下面举例如何对其进行测试。
BarConfiguration :
@Configuration @EnableConfigurationProperties(BarConfiguration.BarProperties.class) public class BarConfiguration { @Autowired private BarProperties barProperties; @Bean public Bar bar() { return new Bar(barProperties.getName()); } @ConfigurationProperties("bar") public static class BarProperties { private String name; public String getName() { return name; } public void setName(String name) { this.name = name; } } } |
BarConfigurationTest :
public class BarConfigurationTest { private AnnotationConfigApplicationContext context; @BeforeMethod public void init() { context = new AnnotationConfigApplicationContext(); } @AfterMethod(alwaysRun = true) public void reset() { context.close(); } @Test public void testBarCreation() { EnvironmentTestUtils.addEnvironment(context, "bar.name=test"); context.register(BarConfiguration.class, PropertyPlaceholderAutoConfiguration.class); context.refresh(); assertEquals(context.getBean(Bar.class).getName(), "test"); } } |
注意到因为我们使用了Configuration Properties机制,需要注册 PropertyPlaceholderAutoConfiguration ,否则在BarConfiguration里无法注入BarProperties。