Reading application.properties in Spring Boot

@SpringBootTest
public class AppPropertiesTests {

    @Autowired
    private Environment env;

    @Value("${test.hello}")
    private String hello;

    @Test
    public void test() {
        System.out.println(env.getProperty("spring.profiles.active"));
        System.out.println(hello);
    }
}

package com.example.demo.model;

import java.util.List;
import java.util.Map;

import lombok.Data;

@Data
public class Mail {
 
    private String host;
    private int port;
    private String from;
    private List<String> defaultRecipients;
    private Map<String, String> additionalHeaders;
    private Credentials credentials;
  
}

package com.example.demo.config;

import com.example.demo.model.Mail;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.core.env.Environment;
import org.springframework.stereotype.Component;

import lombok.Data;

/**
 * ConfigProperties
 */
@Data
@Component
@ConfigurationProperties(prefix = "app")
public class AppProperties {

    @Autowired
    private Environment env;

    private String url;
    private Mail mail;

    public String get(String key) {

        return env.getProperty(key);
    }
}

package com.example.demo.config;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.core.env.Environment;

import com.example.demo.config.AppProperties;

import static org.assertj.core.api.Assertions.assertThat;

/**
 * ConfigPropertiesTests
 */
@SpringBootTest
public class AppPropertiesTest {

    @Autowired
    private AppProperties appProperties;

    @Autowired
    private Environment env;

    @Value("${test.hello}")
    private String hello;

    @Test
    public void test() {

        assertThat(env.getProperty("spring.profiles.active")).asString().isEqualTo("local");
        assertThat(appProperties.getUrl()).isEqualTo("www.test.com");
        assertThat(appProperties.getMail().getHost()).isEqualTo("mailer@mail.com");

    }
}