java - How to test Classes with @ConfigurationProperties and @Autowired

Question

I want to test small parts of the application that rely on properties loaded with @Autowired and @ConfigurationProperties. I am looking for a solution loading only the required properties and not always the whole ApplicationContext. Here as reduced example:

@TestPropertySource(locations = "/SettingsTest.properties")
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {TestSettings.class, TestConfiguration.class})
public class SettingsTest {
    @Autowired
    TestConfiguration config;

    @Test
    public void testConfig(){
        Assert.assertEquals("TEST_PROPERTY", config.settings().getProperty());
    }
}

Configuration Class:

public class TestConfiguration {
    @Bean
    @ConfigurationProperties(prefix = "test")
    public TestSettings settings (){
        return new TestSettings();
    }
}

Settings Class:

public class TestSettings {
    private String property;

    public String getProperty() {
        return property;
    }

    public void setProperty(String property) {
        this.property = property;
    }
}

The properties file in the resource folder contains the entry:

test.property=TEST_PROPERTY

In my current setup config is not null, but no fields are available. The reason the fields are not field should have something to do with the fact that I am not using Springboot but Spring. So what would be the Springboot way to get this running?

edit: The reason why I want to do this is: I have a parser that parses Textfiles, the regular expressions used are stored in a properties file. To test this I would like to load only the properties needed for this parser which are in the exaple above the TestSettings.

While reading the comments I already noticed that this are no Unit tests anymore. However using the full Spring boot configuration for this small test seems a bit too much to me. That's why I asked if there is a posibilty to load only the one class with properties.

Answer 1

You need to annotate your TestConfiguraion with @EnableConfigurationProperties as follows:

@EnableConfigurationProperties
public class TestConfiguration {

    @Bean
    @ConfigurationProperties(prefix = "test")
    public TestSettings settings (){
        return new TestSettings();
    }
}

Also you only need to include TestConfiguration.class in @ContextConfiguration of you SettingsTest class:

@TestPropertySource(locations = "/SettingsTest.properties")
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = TestConfiguration.class)
public class SettingsTest {
...