Today I held a mock dojo (one and a half hour) in order to introduce mocking and JMock to my audience. This post is intended to be the first. Too hard to test things that involve external components? • Too slow, even if you could? • Unit Tests as much fun as smacking yourself in the head with a. Here is a tutorial about using JUnit and EasyMock (a mocking library I personally find far easier to use than JMock).

Author: Vinos Yozshull
Country: Armenia
Language: English (Spanish)
Genre: Education
Published (Last): 12 July 2011
Pages: 269
PDF File Size: 6.92 Mb
ePub File Size: 16.80 Mb
ISBN: 188-5-18482-389-1
Downloads: 62618
Price: Free* [*Free Regsitration Required]
Uploader: Fenrijora

This might be the first test for an object tuyorial will become more complicated. In the following JUnit test class, each test will verify the correct execution of persistence operations, as well as the expected invocations to the e-mail API. Software jMock 2 Java 1. This part is represented by the anonymous inner class context.

There’s a well known article about mock objects and how they relate to “stubs”, another common testing strategy for simplifying external dependencies. Note that you can make JMock simulate that an exception was thrown, by tuutorial the will throwException new MyException. And before someone jumps in with their favourite alternative mocking framework, I’m not sure that’s really the point.

java – How to get started with testing(jMock) – Stack Overflow

For information on using JMockit Coverage with Mavensee the relevant section in that chapter. Fortunately, JMock defines an jmofk so it can mock classes too.

Email Required, but never shown. Kathy Van Stone There’s an interface Calculator aimed tutofial perform math. Put the following code in this interface: More advanced topics are covered in other tutorials 4. Hope it answers the question.


In order to verify the e-mail was correctly sent, the test could mock the e-mail sending API, while exercising the real code in every other component an alternative would be to set up some kind of fake e-mail server which could be jmocck in an assertion at the end of the test. In this tutorial we examine the APIs available in the library, with the help of example tests using Java 8.

jMock for beginners

First we must import tutorjal jMock classes, define our test fixture class and define a test case method. Anson November 5, at 7: Therefore, the service class has two tuotrial dependencies, one for persistence and another for e-mail.

In both cases you setup the system by setting the map to have the properties you want to test and then check that the cache has the same properties as it is a straight delegate.

There’s a class CalculatingMachine aimed to connect Calculator and Printer: Include following jars in its classpath: These days, I find myself writing unit tests with mocks at a slightly higher level, around a small cluster of objects. By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

The Subscriber interface looks like this: The context mocks out the objects that the Publisher collaborates with in this case a Subscriber and checks that they are used correctly during the test. We can shave a few lines off here and there, but it’s more important to understand the design issues.

Notify me of new comments via email. Also your class doesn’t really do anything except delegate which is why you feel like you are not testing much. You are commenting using your Twitter account. Sign up or log in Sign up using Google. So, we end up with something like this:.


As far as I understand CalculatingMachine only requires one test: We want to test the Publisher, which involves testing its interactions with its Subscribers.

Effective Java, 2nd edition, Item The need for a mock should be the exception, not the rule. As you can see, JMock can mock objects through the already-well-known context object. Sign up using Facebook. Traditionally, a mock object is an instance of a class specifically implemented for a single test or set of related tests.

The third one can be achieved with a third-party API for sending e-mail, which in this example is Apache’s Commons Email library. We don’t need to specify what will be returned from the receive method because it has a void return type. To find out more, including how to control cookies, see here: Post as a guest Name. Is there any other way to test all the same but with less code?

JMockit – Tutorial – Introduction

The various mocking frameworks that exist give you mechanisms to create “fake” objects that take the place of these dependencies. Tuutorial up or log in Sign up using Google. In order to do that, we need to have an exception to be thrown while reading document content. Keep in mind that this object doesn’t implement the behavior of the object it’s mocking.