@Value not set via Java-configured test context

With Spring 4, it's now possible to use TestPropertySource:

@TestPropertySource(value="classpath:/config/test.properties")

In order to load specific properties for a junit test

In addition to Biju Kunjummen answer:

If you use @ConfigurationProperties to inject properties into bean setters, then ConfigurationPropertiesBindingPostProcessor need to be created (instead of PropertySourcesPlaceholderConfigurer):

@Configuration
static class PropertyConfig {
    @Bean
    public static ConfigurationPropertiesBindingPostProcessor propertiesProcessor() {
        return new ConfigurationPropertiesBindingPostProcessor();
    }
}

The issue here is you need a PropertySourcesPlaceholderConfigurer also which is actually responsible for resolving the ${..} fields, just add another bean which creates this bean:

@Bean
public static PropertySourcesPlaceholderConfigurer propertiesResolver() {
    return new PropertySourcesPlaceholderConfigurer();
}