Why is a bean created twice in test when using #PostConstruct? - spring-boot

Question

I have a configuration class that uses a properties file and it works properly.
Now I want to test that code and I have to recognize that the method annotated with #PostConstruct is run twice during the test. (In debug mode I can see that the for-loop is conducted twice.)
The configuration class:
#Slf4j
#RequiredArgsConstructor
#Configuration
#ConfigurationPropertiesScan("com.foo.bar")
public class MyConfig {
private final MyProperties myProperties;
#Autowired
private GenericApplicationContext applicationContext;
#PostConstruct
void init() {
Objects.requireNonNull(myProperties, "myProperties may not be null");
for (final MyProperties.MyNestedProperty nested : myProperties.getApps()) {
log.info("xxx {} created.", nested.getName());
applicationContext.registerBean(nested.getName(), MyContributor.class, nested);
}
}
}
The used properties class:
#Slf4j
#Data
#Validated
#ConfigurationProperties(prefix = MyProperties.CONFIG_PREFIX)
public class MyProperties {
public static final String CONFIG_PREFIX = "xxx";
#Valid
#NestedConfigurationProperty
private List<MyNestedProperty> apps;
#Data
public static class MyNestedProperty {
#NotNull
#NotEmpty
private String abc;
private String xyzzy;
#NotNull
#NotEmpty
private String name;
}
}
My attempt with the test class:
#ExtendWith(SpringExtension.class)
#RequiredArgsConstructor
#ContextConfiguration(classes = MyConfigTest.MyTestConfiguration.class)
class MyConfigTest {
#MockBean
MyProperties myProperties;
ApplicationContextRunner context;
#BeforeEach
void init() {
context = new ApplicationContextRunner()
.withBean(MyProperties.class)
.withUserConfiguration(MyConfig.class)
;
}
#Test
void should_check_presence_of_myConfig() {
context.run(it -> {
assertThat(it).hasSingleBean(MyConfig.class);
});
}
// #Configuration
#SpringBootConfiguration
// #TestConfiguration
static class MyTestConfiguration {
#Bean
MyProperties myProperties() {
MyProperties myProperties = new MyProperties();
MyProperties.MyNestedProperty nested = new MyProperties.MyNestedProperty();
nested.setName("xxx");
nested.setAbc("abc");
nested.setXyz("xyz");
myProperties.setApps(List.of(nested));
return myProperties;
}
}
}
Why does this happen and how can I prevent this behaviour?