autoparams-mockito

autoparams-mockito is an extension of the AutoParams library that facilitates the creation of mocks for interfaces and abstract classes using Mockito, a popular mocking framework in Java. By integrating these two libraries, you can seamlessly generate mock objects for your tests.

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>9.0.0</version>
</dependency>

Gradle (Groovy)

For Gradle Groovy DSL, use:

testImplementation 'io.github.autoparams:autoparams-mockito:9.0.0'

Gradle (Kotlin)

For Gradle Kotlin DSL, use:

testImplementation("io.github.autoparams:autoparams-mockito:9.0.0")

Generating Test Doubles with Mockito

Consider a situation where you have an interface that abstracts certain services:

Java

public interface Dependency {

    String getName();
}

Kotlin

interface Dependency {

    val name: String
}

You also have a system that relies on this Dependency interface:

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
}

To generate mock objects for interfaces or abstract classes, the autoparams-mockito extension provides the MockitoCustomizer. When you decorate your test method with @Customization(MockitoCustomizer.class), the @AutoSource annotation will employ Mockito to create mock values for the specified parameters.

Here's how you can apply this in practice:

Java

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

Kotlin

import org.mockito.kotlin.whenever

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

In the above example:

• The stub argument is a mock generated by Mockito, thanks to the MockitoCustomizer.
• The @Freeze annotation ensures that this mock object (stub) is reused as a parameter for the construction of the SystemUnderTest object (sut).

This integration simplifies the creation of mock objects for parameterized tests, making testing more efficient and straightforward.