autoparams-mockito

autoparams-mockito is an extension of AutoParams that enables the automatic creation of test doubles for interfaces and abstract classes using Mockito, a widely used mocking framework for Java. With this extension, AutoParams can generate test doubles seamlessly—with minimal setup.

Install

Maven

For Maven, you can add the following dependency to your pom.xml:

<dependency>
  <groupId>io.github.autoparams</groupId>
  <artifactId>autoparams-mockito</artifactId>
  <version>10.2.0</version>
</dependency>

Gradle (Groovy)

For Gradle Groovy DSL, use:

testImplementation 'io.github.autoparams:autoparams-mockito:10.2.0'

Gradle (Kotlin)

For Gradle Kotlin DSL, use:

testImplementation("io.github.autoparams:autoparams-mockito:10.2.0")

Generating Test Doubles with Mockito

Suppose you have an interface that represents a dependency:

Java

public interface Dependency {

    String getName();
}

Kotlin

interface Dependency {

    val name: String
}

And a system under test that relies on this dependency:

Java

public class SystemUnderTest {

    private final Dependency dependency;

    public SystemUnderTest(Dependency dependency) {
        this.dependency = dependency;
    }

    public String getMessage() {
        return "Hello " + dependency.getName();
    }
}

Kotlin

class SystemUnderTest(private val dependency: Dependency) {

    val message: String
        get() = "Hello ${dependency.name}"
}

By using the @Customization(MockitoCustomizer.class) annotation, AutoParams will automatically generate Mockito-based test doubles for eligible parameters (such as interfaces and abstract classes).

Here’s an example:

Java

@Test
@AutoParams
@Customization(MockitoCustomizer.class)
void testMethod(@Freeze Dependency stub, SystemUnderTest sut) {
    when(stub.getName()).thenReturn("World");
    assertEquals("Hello World", sut.getMessage());
}

Kotlin

@Test
@AutoKotlinParams
@Customization(MockitoCustomizer::class)
fun testMethod(@Freeze stub: Dependency, sut: SystemUnderTest) {
    whenever(stub.name).thenReturn("World")
    assertEquals("Hello World", sut.message)
}

In this test:

• stub is a test double automatically generated by Mockito.
• The @Freeze annotation ensures that the same stub instance is injected into the SystemUnderTest.
• You can configure the test double using standard Mockito syntax.

This integration streamlines test setup, enabling you to focus on verifying behavior rather than wiring dependencies manually.