How to test spring configuration classes?

Question

I have a spring application whith configuration classes where instance the beans.

Aplication class:

@Configuration @EnableAspectJAutoProxy @EnableSpringDataWebSupport @EnableTransactionManagement @ComponentScan(basePackageClasses = Application.class) @PropertySource(value = {"classpath:foo.properties"}) @EnableJpaRepositories(basePackageClasses = Application.class) @EnableJpaAuditing public class Application {      @Inject     private Environment env;      @Bean     JndiTemplate jndiTemplate() {         return new JndiTemplate();     }      @Bean     public DataSource dataSource() {                 DataSource dataSource = getDataSource();         if (dataSource == null) {             dataSource = new BasicDataSource();             ((BasicDataSource) dataSource).setUsername(env.getProperty("jdbc.user"));             ((BasicDataSource) dataSource).setPassword(env.getProperty("jdbc.password""));              ((BasicDataSource) dataSource).setDriverClassName(env.getProperty("jdbc.driverClassName"));             ((BasicDataSource) dataSource).setUrl(env.getProperty("jdbc.url"));         }         return dataSource;     }      @Bean     public PlatformTransactionManager transactionManager() {         EntityManagerFactory factory = entityManagerFactory().getObject();         return new JpaTransactionManager(factory);     }      //.... } 

MvcConfiguration class:

@Configuration @ComponentScan(basePackageClasses = Application.class, includeFilters = @Filter({Controller.class, Component.class}), useDefaultFilters = true) class MvcConfiguration extends WebMvcConfigurationSupport {     private static final String MESSAGES = "classpath:/i18n";      private static final String VIEW_PREFIX = "/WEB-INF/views/";      @Inject     private Environment env;      @Override     public RequestMappingHandlerMapping requestMappingHandlerMapping() {         RequestMappingHandlerMapping requestMappingHandlerMapping = super.requestMappingHandlerMapping();         requestMappingHandlerMapping.setUseSuffixPatternMatch(false);         requestMappingHandlerMapping.setUseTrailingSlashMatch(true);          return requestMappingHandlerMapping;     }      @Bean(name = "messageSource")     public MessageSource messageSource() {         ReloadableResourceBundleMessageSource messageSource = new ReloadableResourceBundleMessageSource();         messageSource.setBasename(MESSAGES);         messageSource.setCacheSeconds(5);          return messageSource;     }      @Override     public void addResourceHandlers(ResourceHandlerRegistry registry) {         registry.addResourceHandler("/static/").addResourceLocations("/static/**");     }      @Bean     public MultipartResolver filterMultipartResolver(){         CommonsMultipartResolver resolver = new CommonsMultipartResolver();         resolver.setMaxUploadSize(Long.parseLong(env.getProperty("multipart.max.size")));         return resolver;     }      //....  } 

And SecurityConfiguration class:

@Configuration @EnableWebSecurity @EnableGlobalMethodSecurity(prePostEnabled = true) class SecurityConfiguration extends WebSecurityConfigurerAdapter {      @Bean     public PasswordEncoder passwordEncoder() {         return new BCryptPasswordEncoder();     }       //....      @Override     protected void configure(HttpSecurity http) throws Exception {         //Logout por POST con el valor de token csrf         http.authorizeRequests()                 .antMatchers("/static/**").permitAll()                 .anyRequest().authenticated()                 .and()             .formLogin()                 .loginPage("/login")                 .permitAll()                 .failureUrl("/login?error=1")                 .loginProcessingUrl("/authenticate")                 .and()             .logout()                 .logoutUrl("/logout")                 .logoutSuccessUrl("/signin")                 .permitAll();     }  } 

How I can test them with JUnit? How to test the beans are created in the spring context?

Answer 1

In a word - "don't", that way lays madness.

What you really want is higher level tests that make use of your Spring configuration but are still focused on behaviour not implementation.

For example, looking at your security configuration - you don't really care that the configure method is called, or what it does, what you want to test for is:

1. Static pages don't require authentication
2. Other pages do require authentication
3. Logging in works
4. Logging out works

Using Spring for DI and security is merely how those things are implemented whereas your tests should be focused on the fact those things actually work.

Answer 2

I believe this can only be achieved with an Integration Test.

The purpose of Unit Tests are not to check if the whole Spring Context is being created successfully.

You can test each configuration method with a Unit Test by using mocks, etc to check if they are OK, but the whole Spring Context thing is an Integration test.

I use to do this Configuration Test by doing what Spring Docs calls "Spring Unit Test" (that for me is more like a Integration Test of the Controllers + Views)

The idea is that, if you can get a Spring Context running for a Controller integration Test, then your Configurations are OK.

There is a whole chapter in spring docs on how to do that kind of test. http://docs.spring.io/spring/docs/current/spring-framework-reference/html/testing.html