Easy Random/Faker JUnit 5 extension
The simple, stupid random Java™ beans generator for JUnit 5

The easy random extension provides a test with randomly generated objects, including:

• JDK types: int/double/BigDecimal/boolean/String etc
• Custom types: POJO, except for records support
• Generic collections: List/Set/Stream/Array
• Java Faker support: Name, Internet, Address etc
• Data Faker support: Name, Internet, Address etc
• Javax/Jakarta Validation annotations: @Email, @Pattern etc
• Custom Annotation with Validation annotation, such as @Phone. For more https://any86.github.io/any-rule/

@Documented
@Constraint(validatedBy = {})
@Target({METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE})
@Retention(RUNTIME)
@Pattern(regexp = "^1[3-9]\\d{9}$")
public @interface Phone {
}

• i18n friendly to Faker's types

import com.github.javafaker.Address  
  
@Test
public void testAddress(@Random(locale = "zh_CN") Address address) {
  System.out.println(address.cityName());
}

How to use?

Include following dependency in your pom.xml

  <dependency>
    <groupId>org.mvnsearch</groupId>
    <artifactId>easy-random-junit5-extension</artifactId>
    <version>0.5.0</version>
    <!--<version>0.2.0</version> for Java 8 & 11-->
    <scope>test</scope>
  </dependency>

Usage examples:

• Injecting random values as fields:

   import org.jeasy.random.EasyRandomExtension;
   import org.jeasy.random.Random;

   @ExtendWith(EasyRandomExtension.class)
   public class MyTest {
  
       @Random
       private String anyString;
  
       @Random
       private List<DomainObject> domainObjectList;
       
       @Test
       public void testUsingRandomString() {
           // use the injected anyString
           // ...
       }
  
       @Test
       public void testUsingRandomDomainObjects() {
           // use the injected anyDomainObjects
           // the anyDomainObjects will contain _N_ fully populated random instances of DomainObject
           // ...
       }
  
       @Test
       public void testUsingPartiallyPopulatedDomainObject() {
           // use the injected anyPartiallyPopulatedDomainObject
           // this object's "name" and "value" members will not be populated since this has been declared with
           //     excluded = {"name", "value"}
           // ...
       }
   }

• Injecting random values as parameters:

   @ExtendWith(EasyRandomExtension.class)
   public class MyTest {
  
       @Test
       public void testUsingRandomString(@Random @Email String anyString) {
           // use the provided anyString
           // ...
       }
  
       @Test
       public void testUsingRandomDomainObjects(@Random List<DomainObject> anyDomainObjects) {
           // use the injected anyDomainObjects
           // the anyDomainObjects will contain _N_ fully populated random instances of DomainObject
           // ...
       }
   }

JUnit 5 Automatic Extension Registration

With Automatic Extension Registration, and you can remove @ExtendWith(EasyRandomExtension.class) on test class.

• Create src/test/resources/junit-platform.properties with following code:

junit.jupiter.extensions.autodetection.enabled=true

• Remove @ExtendWith(EasyRandomExtension.class) on test class

References and Thanks

• Easy Random: https://github.com/j-easy/easy-random
• RandomBeansExtension: https://glytching.github.io/junit-extensions/randomBeans
• Instancio: a Java library for automating data setup in unit tests https://www.instancio.org/