How to set a @Value in a MicronautTest?

Question

I am using Micronaut as framework for developing an AWS Java Lambda.

Micronaut supports @Value for reading, well, "values".

@io.micronaut.context.annotation.Factory
public class SomeFactory {
  public SomeFactory(
    @io.micronaut.context.annotation.Value("${NameOfValue}") 
    final String value) {
    ...
  }
  ...
}

When testing, I want to set "NameOfValue" to a specific value, how can I do that?

@io.micronaut.test.annotation.MicronautTest
class SomeLambdaIT {

  @org.junit.jupiter.api.Test
  void aTest() {
    // When this test runs, "NameOfValue" shall be set to a specific value
  }
}

Answer 1

When testing, I want to set "NameOfValue" to a specific value, how can I do that?

You have a number of options.

One option is to define src/test/resources/application-test.yml and define the config setting there. That file will only be loaded in the test environment and any settings defined in that file will supersede values defined in src/main/resources/application.yml.

Another option that might make sense if you only want the special setting in play for this particular test is you can do something like this...

import io.micronaut.test.annotation.MicronautTest;
import org.junit.jupiter.api.Test;


@MicronautTest(propertySources = "classpath:some-special-test-props.properties")
public class SomeTest {

    @Test
    void someTest() {
        // ...
    }
}

Then define src/test/resources/some-special-test-props.properties and assign the value there.

Yet another option is to mark your test with @Property:

import io.micronaut.context.annotation.Property;
import io.micronaut.test.annotation.MicronautTest;
import org.junit.jupiter.api.Test;

@MicronautTest
@Property(name="some.config.value", value = "My Test Value")
public class SomeTest {


    @Test
    void someTest() {
        // ...
    }
}

I hope that helps.

EDIT

A comment below includes "I did give it a try, but the @Property solution nor the some-special-test-props.properties works in my case.". I have created a sample app demonstrating each of these techniques. See the project at https://github.com/jeffbrown/markusschultevalue.

https://github.com/jeffbrown/markusschultevalue/blob/8131e96492356180e2c7fade09603bd41f8c8829/src/main/java/markusschultevalue/SomeWidget.java

package markusschultevalue;

public class SomeWidget {
    private final String name;

    public SomeWidget(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }
}

https://github.com/jeffbrown/markusschultevalue/blob/master/src/main/java/markusschultevalue/SomeFactory.java

package markusschultevalue;

import io.micronaut.context.annotation.Bean;
import io.micronaut.context.annotation.Factory;
import io.micronaut.context.annotation.Value;

@Factory
public class SomeFactory {

    private final String name;

    // there are better ways to do this but
    // this is consistent with the code in the
    // question being asked...
    public SomeFactory(@Value("${some.config.value}") String name) {
        this.name = name;
    }

    @Bean
    public SomeWidget createWidget() {
        return new SomeWidget(name);
    }
}

https://github.com/jeffbrown/markusschultevalue/blob/8131e96492356180e2c7fade09603bd41f8c8829/src/test/java/markusschultevalue/PropertyAnnotationTest.java

package markusschultevalue;

import io.micronaut.context.annotation.Property;
import io.micronaut.test.annotation.MicronautTest;
import org.junit.jupiter.api.Test;

import javax.inject.Inject;

import static org.junit.jupiter.api.Assertions.assertEquals;

@MicronautTest
@Property(name="some.config.value", value="Some Widget Name")
public class PropertyAnnotationTest {

    @Inject
    SomeWidget someWidget;

    @Test
    void testWidget() {
        assertEquals("Some Widget Name", someWidget.getName());
    }
}

https://github.com/jeffbrown/markusschultevalue/blob/8131e96492356180e2c7fade09603bd41f8c8829/src/test/java/markusschultevalue/ConfigFileTest.java

package markusschultevalue;

import io.micronaut.test.annotation.MicronautTest;
import org.junit.jupiter.api.Test;

import javax.inject.Inject;

import static org.junit.jupiter.api.Assertions.assertEquals;

// This will load the config value
// from src/test/resources/some-widget-test-config.yml
@MicronautTest(propertySources = "classpath:some-widget-test-config.yml")
public class ConfigFileTest {

    @Inject
    SomeWidget someWidget;

    @Test
    void testWidget() {
        assertEquals("Some Other Widget Name", someWidget.getName());
    }
}

https://github.com/jeffbrown/markusschultevalue/blob/8131e96492356180e2c7fade09603bd41f8c8829/src/test/resources/some-widget-test-config.yml

some:
  config:
    value: Some Other Widget Name

Note that in your example you are referencing a config variable with "${NameOfValue}". If that is actually the name of your config variable, note that in code you need to reference that in valid kebab-case which would be "${name-of-value}".

I hope that helps.