@SpringBootTest注解 --基于SpringBoot2.5.7版本

可以在运行基于Spring Boot的测试的测试类上指定的注释。在常规的Spring TestContext框架之上提供了以下特性:

• 默认提供SpringBootContextLoader作为ContextLoader，也通过 @ContextConfiguration(loader=…)来自定义

• 若没有显示指定，将查找嵌套的@Configuration类，然后返回到SpringBootConfiguration搜索配置

• 允许使用properties属性定义自定义环境属性。

• 允许使用args属性定义应用程序参数。

• 支持不同webEnvironment模式,包括自定义运行web服务器监听或默认为随机端口

• web服务模式下，自动注册一个TestRestTemplate和/或WebTestClient bean用于web测试

关于 aliasFor可以参考 spring 官方

@Target(ElementType.TYPE)//注解只能用于Class, interface (including annotation type), or enum declaration
@Retention(RetentionPolicy.RUNTIME)//注释将由编译器记录在类文件中，并在运行时由VM保留，因此可以反射性地读取它们。
@Documented
@Inherited //允许子类继承
@BootstrapWith(SpringBootTestContextBootstrapper.class)
@ExtendWith(SpringExtension.class)
public @interface SpringBootTest {

	/**
	 * Alias for {@link #properties()}.
	 * @return the properties to apply
	 */
	@AliasFor("properties")
	String[] value() default {};

	/**
	 * Properties in form {@literal key=value} that should be added to the Spring
	 * {@link Environment} before the test runs.
	 * @return the properties to add
	 */
	@AliasFor("value")
	String[] properties() default {};

	/**
	 * Application arguments that should be passed to the application under test.
	 * @return the application arguments to pass to the application under test.
	 * @see ApplicationArguments
	 * @see SpringApplication#run(String...)
	 * @since 2.2.0
	 */
	String[] args() default {};

	/**
	 * The <em>component classes</em> to use for loading an
	 * {@link org.springframework.context.ApplicationContext ApplicationContext}. Can also
	 * be specified using
	 * {@link ContextConfiguration#classes() @ContextConfiguration(classes=...)}. If no
	 * explicit classes are defined the test will look for nested
	 * {@link Configuration @Configuration} classes, before falling back to a
	 * {@link SpringBootConfiguration @SpringBootConfiguration} search.
	 * @see ContextConfiguration#classes()
	 * @return the component classes used to load the application context
	 */
	Class<?>[] classes() default {};

	/**
	 * The type of web environment to create when applicable. Defaults to
	 * {@link WebEnvironment#MOCK}.
	 * @return the type of web environment
	 */
	WebEnvironment webEnvironment() default WebEnvironment.MOCK;

	/**
	 * An enumeration web environment modes.
	 */
	enum WebEnvironment {

		/**
		 * Creates a {@link WebApplicationContext} with a mock servlet environment if
		 * servlet APIs are on the classpath, a {@link ReactiveWebApplicationContext} if
		 * Spring WebFlux is on the classpath or a regular {@link ApplicationContext}
		 * otherwise.
		 */
		MOCK(false),

		/**
		 * Creates a web application context (reactive or servlet based) and sets a
		 * {@code server.port=0} {@link Environment} property (which usually triggers
		 * listening on a random port). Often used in conjunction with a
		 * {@link LocalServerPort @LocalServerPort} injected field on the test.
		 */
		RANDOM_PORT(true),

		/**
		 * Creates a (reactive) web application context without defining any
		 * {@code server.port=0} {@link Environment} property.
		 */
		DEFINED_PORT(true),

		/**
		 * Creates an {@link ApplicationContext} and sets
		 * {@link SpringApplication#setWebApplicationType(WebApplicationType)} to
		 * {@link WebApplicationType#NONE}.
		 */
		NONE(false);

		private final boolean embedded;

		WebEnvironment(boolean embedded) {
			this.embedded = embedded;
		}

		/**
		 * Return if the environment uses an {@link ServletWebServerApplicationContext}.
		 * @return if an {@link ServletWebServerApplicationContext} is used.
		 */
		public boolean isEmbedded() {
			return this.embedded;
		}

	}

}

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT,
        properties = "server.port=8081", args = "--spring.application.name=demoTest",
        classes = AppApplication.class)
@Import(MyConfig.class)
public class SpringBootDemoTest {
    @Autowired
    private ApplicationContext applicationContext;
    @Value("${spring.application.name}")
    private String appName;

    @Autowired(required = false)
    private MyConfig myConfig;

    @Test
    void AppApplicationTest() {
        assert ("demoTest".equals(appName));
        assertThat(myConfig).isNotNull().extracting("cfgName").isEqualTo("11");
        assertThat(applicationContext).isNotNull();
    }
}

import lombok.Getter;
import lombok.Setter;

@Getter
@Setter
public class MyConfig {
    private String cfgName = "11";
}

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * @author bearboy80
 */
@SpringBootApplication
public class AppApplication {
    public static void main(String[] args) {
        SpringApplication.run(AppApplication.class, args);
    }
}