Spring Boot: custom properties configuration and tests

Question

I'm using Spring Boot 2.0 with default application.yml properties file. I would like to split it to separate property files because it becomes huge.
Also I would like to write tests to check properties correctness: values that will present on production application context (not the test one).

Here is my property file: src/main/resources/config/custom.yml

my-property:
  value: 'test'

Property class:

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;

@Data
@Configuration
@ConfigurationProperties(prefix = "my-property")
@PropertySource("classpath:config/custom.yml")
public class MyProperty {

  private String value;
}

Test:

import static org.junit.Assert.assertEquals;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@SpringBootTest(classes = MyProperty.class)
@EnableConfigurationProperties
public class MyPropertyTest {

  @Autowired
  private MyProperty property;

  @Test
  public void test() {
    assertEquals("test", property.getValue());
  }

}

But test fails with error:

java.lang.AssertionError: 
Expected :test
Actual   :null

Also I see that property value is null when running the application by printing it in ApplicationRunner.
When I used application.yml for all properties it were well with the same configuration.

How to put correct configuration for properties and tests for make it work?
Link to Github repo

Answer 1

Finely I found the right way for having custom yaml properties in my app.

The issue is that Spring doesn't support yaml files as @PropertySource (link to issue). And here is a workaround how to deal with that described in spring documentation.
So, to be able to load properties from yaml files you need:
* To implement EnvironmentPostProcessor
* To register it in spring.factories

Please visit this github repo for complete example.

Also, thanks a lot for your support, guys!