Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

Shorter Syntax for Creating Stubs with Mockito

DZone's Guide to

Shorter Syntax for Creating Stubs with Mockito

· Java Zone ·
Free Resource

Bring content to any platform with the open-source BloomReach CMS. Try for free.

As part of my efforts to create more concise Unit Tests in Java, Steve McLarnon and I recently added the ability to create a stub and stub one method with only one line.

The implementation relies entirely on Mockito, so my example assumes you were already using Mockito to create the stub.

The Mockito documentation has the following example for stubbing:

LinkedList mockedList = mock(LinkedList.class);
when(mockedList.get(0)).thenReturn("first");
Using the code Steve and I put together you can simplify this to the following single line.
LinkedList mockedList = create(aStub(LinkedList.class).returning("first").from().get(0));
The implementation is simple, but does rely on static state. There are ways to improve the implementation; however, this works for us. If you have more specific needs, feel free to change it to suit you.

The implementation follows:
public class MockitoExtensions {
public static T create(Object methodCall) {
when(methodCall).thenReturn(StubBuilder.current.returnValue);
return (T) StubBuilder.current.mockInstance;
}

public static StubBuilder aStub(Class klass) {
return new StubBuilder(mock(klass));
}

public static class StubBuilder {
public static StubBuilder current;
public final T mockInstance;
private Object returnValue;

public StubBuilder(T mockInstance) {
current = this;
this.mockInstance = mockInstance;
}

public T from() {
return mockInstance;
}

public StubBuilder returning(Object returnValue) {
this.returnValue = returnValue;
return this;
}
}
}

From http://blog.jayfields.com

BloomReach CMS: the API-first CMS of the future. Open-source & enterprise-grade. - As a Java developer, you will feel at home using Maven builds and your favorite IDE (e.g. Eclipse or IntelliJ) and continuous integration server (e.g. Jenkins). Manage your Java objects using Spring Framework, write your templates in JSP or Freemarker. Try for free.

Topics:

Opinions expressed by DZone contributors are their own.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}