Arthur Arts wrote an blog post about Using ArgumentCaptor for generic collections with Mockito. With the ArgumentCaptor in Mockito the parameters of a method call to a mock are captured and can be verified with assertions. In Spock we can also get a hold on the arguments that are passed to a method call of a mock and we can write assertions to check the parameters for certain conditions. When we create a mock in Spock and invoke a method on the mock the arguments are matched using the equals() implementation of the argument type. If they are not equal Spock will tell us by showing a message that there are too few invocations of the method call. Let’s show this with an example. First we create some classes we want to test:
package com.jdriven.spock
class ClassUnderTest {
private final Greeting greeting
ClassUnderTest(final Greeting greeting) {
this.greeting = greeting
}
String greeting(final List<Person> people) {
greeting.sayHello(people)
}
}
package com.jdriven.spock
interface Greeting {
String sayHello(final List<Person> people)
}
package com.jdriven.spock
@groovy.transform.Canonical
class Person {
String name
}
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NOTE: this post was written for Karma 0.8 which required a manual installation of PhantomJS.
However this blog post is still relevant for installing the NodeJS and NPM pre-requisites.
As of 0.10 both PhantomJS and Chrome will be automatically installed by the launcher plugins.
Installation instructions for Karma 0.10 can be found here (a "Local installation" is preferred).
Furthermore instructions on how to install plugins (introduced as of 0.10) can be found here.
Recently I decided to switch from the “Jasmine Maven Plugin” (using the Mozilla Rhino JavaScript “emulator”) to the Karma (previously called Testacular) test runner. The big advantage of Karma opposed to the “Jasmine Maven Plugin” is that it uses actual browsers (like Chrome, Firefox, Safari and even IE) to execute the tests. This blogpost describes the installation and configuration of Karma on Windows. To install Karma you first need to install NodeJS and its NPM (NodeJS Package Manager). Additionally you could install PhantomJS, a “headless” web-kit browser, to run your JavaScript tests from the command-line without spawning unwanted browser windows. Instead of using PhantomJS as a replacement for testing against real browsers you could use it to run tests on your local development machine while your continuous integration server could then run your tests on “all” relevant browsers.
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Albert van Veen wrote a blog post about Using ArgumentMatchers with Mockito. The idea is to let a mocked or stubbed service return a different value based on the argument passed into the service. This is inspired me to write the same sample with Spock. Spock already has built-in mock and stub support, so first of all we don’t need an extra library to support mocking and stubbing. We can easily create a mock or stub with the Mock() and Stub() methods. We will see usage of both in the following examples. In the first example we simply return true or false for ChocolateService.doesCustomerLikesChocolate() in the separate test methods.
import spock.lang.*
public class CandyServiceSpecification extends Specification {
private ChocolateService chocolateService = Mock()
private CandyService candyService = new CandyServiceImpl()
def setup() {
candyService.chocolateService = chocolateService
}
def "Customer Albert really likes chocolate"() {
given:
final Customer customer = new Customer(firstName: 'Albert')
and: 'Mock returns true'
1 * chocolateService.doesCustomerLikesChocolate(customer) >> true
expect: 'Albert likes chocolate'
candyService.getCandiesLikeByCustomer(customer).contains Candy.CHOCOLATE
}
def "Other customer do not like chocolate"() {
given:
final Customer customer = new Customer(firstName: 'Any other firstname')
and: 'Mock returns false'
1 * chocolateService.doesCustomerLikesChocolate(customer) >> false
expect: 'Customer does not like chocolate'
!candyService.getCandiesLikeByCustomer(customer).contains(Candy.CHOCOLATE)
}
}
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Say you want to test a method from class which extends some kind of superclass. Sometimes you can be dependent on code in the superclass, which is undesirable in a test. Now actually, the first thing you should consider is to refactor your code, because it’s violating the Single Responsibility design principle: there is more than one reason why your class is subject to change. Another advice is to favor composition over inheritence. In this way you can mock the code you are collaborating with. Having said that, sometimes you run into legacy code you just have to work with and aren’t able to refactor due to circumstances. Here’s a trick I found on Stackoverflow to “mock” a superclass method to do nothing with mockito.
public class BaseController {
public void method() {
validate(); // I don't want to run this!
}
}
public class JDrivenController extends BaseController {
public void method(){
super.method()
load(); // I only want to test this!
}
}
@Test
public void testSave() {
JDrivenController spy = Mockito.spy(new JDrivenController());
// Prevent/stub logic in super.method()
Mockito.doNothing().when((BaseController)spy).validate();
// When
spy.method();
// Then
verify(spy).load();
}
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Willem Cheizoo already wrote an blog post about How to test for an exception with JUnit and this inspired me to write the same sample with Spock. In Spock we can use the thrown() method to check for exceptions. We can use it in a then: block of our test.
import spock.lang.*
public class JDrivenServiceSpecification extends Specification {
private JDrivenService service = new JDrivenService()
def "publishArticle throws ArticleNotFoundException() {
when:
service.publishArticle null
then:
final ArticleNotFoundException exception = thrown()
// Alternate syntax: def exception = thrown(ArticleNotFoundException)
exception.message == 'Article not found please provide an article to publish'
}
}
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Testing for exceptions in JUnit is something we have to deal with! We want to test if an exception occurs in a particular situation, or even if the exception contains a particular message. The question is: How to test for an exception in Junit? What we see very often is this:
import org.junit.Test;
public class JDrivenServiceTest {
JDrivenService service = new JDrivenService();
@Test(expected = ArticleNotFoundException.class)
public void testPublishArticle_WithException() throws Exception {
service.publishArticle(null);
}
}
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Mockito is a mock framework which you can use to write simple and clean tests. One of it’s nice features is the ArgumentMatcher. With the ArgumentMatcher you can determine the outcome of your mocked service or repository based on any condition you want. Imagine we have a CandyService which can get a list of candies which are liked by a specific customer. This service uses the external ChocalateService which specifically checks if the customer likes chocolate. The CandyServiceTest class looks like this:
@RunWith(MockitoJUnitRunner.class) // will initiate and inject the mocks
public class CandyServiceTest {
@Mock
private ChocolateService chocolateService;
@InjectMocks
private CandyService candyService = new CandyServiceImpl();
@Test
public void testCustomerLikesChocolate() throws ParseException {
Customer customer = new Customer();
customer.setFirstName("Albert");
List candiesLikedByCustomer = candyService.getCandiesLikeByCustomer(customer);
assertTrue(candiesLikedByCustomer.contains(Candy.CHOCOLATE), "Expected customer to like chocolate");
}
@Test
public void testCustomerWhoNotLikesChocolate() throws ParseException {
Customer customer = new Customer();
customer.setFirstName("Any other firstname");
List candiesLikedByCustomer = candyService.getCandiesLikedByCustomer(customer);
assertFalse(candiesLikedByCustomer.contains(Candy.CHOCOLATE), "Expected customer not to like chocolate");
}
}
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Since Grails 2.1 we can create a Grails wrapper. The wrapper allows developer to run Grails commands in a project without installing Grails first. The wrapper concept is also available in other projects from the Groovy ecosystem like Gradle or Griffon. A wrapper is a shell script for Windows, OSX or Linux named grailsw.bat or grailsw and a couple of JAR files to automatically download a specific version of Grails. We can check in the shell scripts and supporting files into a version control system and make it part of the project. Developers working on the project simply check out the code and execute the shell script. If there is no Grails installation available then it will be downloaded. To create the shell scripts and supporting files someone on the project must run the wrapper command for the first time. This developer must have a valid Grails installation. The files that are generated can then be added to version control and from then one developers can use the grailsw or grailsw.bat shell scripts.
$ grails wrapper
| Wrapper installed successfully
$
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When experimenting with AngularJS features I often create a so-called Plunk on http://plnkr.co/. Although this site provides built-in templates for AngularJS, I found it useful to create my own since:
- The “1.0.x (stable)” / “1.0.2 + Jasmine” templates use old versions of AngularJS;
- “1.0.2 + Jasmine” template solely outputs Jasmine results but no AngularJS content.
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Next to creating controllers and directives, AngularJS also supports “singleton” services. Services, like on the server-side, offer a great way for separating logic from your controllers. In AngularJS anything that’s either a primitive type, function or object can be a service. Although the concept of service is quite straight forward, the declaration of them in AngularJS isn’t:
- There are 4 different ways to declare a service.
- Registering a existing value as a service
- Registering a factory function to create the singleton service instance
- Registering a constructor function to create the singleton service instance
- Registering a service factory which can be configured
- Only 1 of them is extensively documented
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