How To Write Junit Test Cases For Void Method In Java Using Mockito

Mock a simple method using PowerMock. Testing with JUnit is one of the most valuable skills a Java developer can learn. In this blog, I will show, how we can test our void method using Mockito. I’m fascinated by how easy it is to use, compared to other things out there both in the Java and. Spring Boot + JUnit 5 + Mockito. JUnit: A unit testing framework that is extensively used to test the code written in Java. So, if a test constructor or a @Test, @BeforeEach, @AfterEach, @BeforeAll, or @AfterAll method accepts a parameter, then the parameter must be resolved at runtime by a ParameterResolver. We are using JUnit 5 to write test cases in conjunction with Mockito to mock objects. Develop JUnit test cases to test the Java and calculator EJB. i have called 2 levels to test that number of times called gives some positive value but The reason I say that is this code. The following code snippet shows a simple JUnit test which tests the toString conversation of a PercentType. Step 13 - Tip - Giving a name to a Parameterized Test. Creating a battery of good unit test cases is an important part of ensuring the quality of your application over its lifecycle. Inside the class one can refer to all classes from the host bundle and all imported classes. A unit testing framework for Extract-Transform-Load processes, written in Java. When unit testing code with JMS you’ll typically want to avoid the overhead of running separate proceses; plus you’ll want to increase startup time as fast as possible as you tend to run unit tests often and want immediate feedback. Method used by the test to inject the config resource public void setConfigResource(IConfigResource configResource) { this. x is increasingly popular for writing reactive applications on the JVM. Mockito library enables mocks creation, verification and stubbing. I'm not sure if it is used correctly. JUnit Jupiter is the new API for writing tests and extensions in JUnit 5 Finally, JUnit Vintage allows us to run JUnit 4 tests with JUnit 5 One of the biggest flaws of JUnit 4 is that it does not support multiple runners (so you cannot use e. In this simple example we are going to write a mock object test for a publish/subscribe message system. It is an instance of the xUnit architecture for unit testing frameworks. Samplers perform the actual work of JMeter Junit test case for jdbc connection. Mockito doAnswer() method takes Answer as argument. Tests should hook into the existing junit framework. In the sample below we have two test cases, testCaseNaive() will try to do the thing that should work out of the box. CoreMatchers. JUnit is a Java library to help you perform unit testing. Capable of testing Oracle, Informatica, SqlServer, PostGreSQL, MySQL, etc. Internally, a mock is nothing but a proxy for the actual class instance. The sample results have various attributes (success/fail, elapsed time, data size etc. Both unit tests should test the class DefaultMassMailSender and its public method that should select users with user names starting with a given string and send them email messages with. It is an instance of the xUnit architecture for In the second test-case we wrote, the implementation of the method was actually called. I was trying to write the way you. run(ParentRunner. It provides many simple annotations to do so. Don't be afraid of doing something trivial to make the test work. In general it it safe to ignore trivial code. 1 Writing a test case One of the primary XP tenets is that writing and running tests should be easy. In this simple example we are going to write a mock object test for a publish/subscribe message system. This approach is becoming more complicated as the different kinds of tests grow. AW: How to run a single junit test method with ant. @Test public void shouldNotDeletePersonByGivenId() throws Exception { Mockito. MR Unit Provides a mock. For junit 3 we will use our custom implementation of TestSuite class. Also, avoid deploying JUnit and other testing packages with your application. Refer to JUnit Report for specifics. JUnit provides different test runners which can run a test suite and collect the results. Say, if you’ll write a method to add two numbers, it can return a result. First of all tests (unit tests, integration tests, whatever) are not like cake frosting, You don't add them at the end. I wrote up a simple version that takes advantage of some of the syntactical sugar of the Mockito framework import static org. The previous paragraph was showing kind of the basics of using Mockito. ] In continuation of my earlier blogs on Introduction to Spring MVC and Testing DAO layer in Spring MVC, in this blog I will demonstrate how to test Service layer in Spring MVC. NullPointerException: Cannot get property 'mainContext' on null. One of the features of Java 8 is an ability to put default methods in In that case, please spend 4 minutes right now to configure it in your Idea. maven, gradle or jar file. Listing 7: Shows the code. Enjoy learning coding skills in vb script and Java and learn how to develop advance solutions using frameworks. x is increasingly popular for writing reactive applications on the JVM. As you see, we just have a stupid method which has 2 lines of code, we still could not cover it %100. Home » Java » Mockito » Mockito Mock Void Method Most of the times Mockito when() method is good enough to mock an object’s behavior. The requirements to create a test method are that it must be annotated with @Test, be public, take no arguments and return void. Testing using Mockito. Spring Boot + JUnit 5 + Mockito. Both unit tests should test the class DefaultMassMailSender and its public method that should select users with user names starting with a given string and send them email messages with. With the test code in place, we can run this Spock unit test either from the command line (using the mvn test command), or via our favorite IDE. Using safe methods is up to the test developer’s discretion. 0 introduces a completely different API to the older versions. Please find the details as below: log4j2. For this purpose, I am using PowerMockito framework. Java fields and member functions names are case sensitive. It is an instance of the xUnit architecture for unit testing frameworks. This particular version uses dual head and tail pointers. how di check that? referencelettersbean rf = mockito. The first test testInitialize() behaves like any other Mockito test with the exception that we mock it using PowerMockito. @RunWith(MyTestRunner. Test; import org. I realise that the thought of Unit Testing private methods in Java classes can be like a red rag to a bull for some people and I understand the arguments. With Spock, you use Groovy to write more readable and concise tests. Test your stack structure : TestCase « JUnit « Java Tutorial. class) annotation tells the test runner to run tests in this class. In Python the runtime type of the variable is used, so if the static method is overridden, the overridden version will be called. If you want to test any void method from junit and mockito go for mockito. Below are the ways to write your customized classes. Methods with return values can be tested by asserting the returned value, but how to test void methods? The void method that you want to test could either be calling other methods to get things done or processing the input parameters or maybe generating some values or all of it. Samplers perform the actual work of JMeter Junit test case for jdbc connection. How to join two Lists in Java. When unit testing such methods, if we only used JUnit, our tests will also depend on those Mockito is a mocking framework that tastes really good. The sample results have various attributes (success/fail, elapsed time, data size etc. This article contains some basic and interesting Java code examples for beginners. @Before - Things to be done before each test case. Note that core, java and junit files all need to be the same file version e. The tutorial Junit Mockito Verify method will show you how to verify a Java class method has been executed at least once or not. Note that if you are using assertEquals(), the expected output must match exactly, character for character, including all newlines. With Mockito, creating mock objects is very easy. Here is an example with Eclipse. methods in java are not very happy to accept void as the argument type! Effectively, in the above syntax the when method is taking void as one of the argument! Well this is a problem. my void method changes boolean variable value in class. Note here: Adding to an empty queue is a little different than adding to a queue that already has elements, because we have to update the head in the former case but not the latter. private void compare Set JUnit Test case fail. A JUnit test fixture is a Java object. JUnit is a program that can be used to perform unit testing of software by writing test cases in Java. \\ Other Hadoop Test case requirements * DO begin all your test classes with the word {{Test}}. public class TestMyStack extends TestCase { public void being tested in test case method:. sleep(1000) or some other mechanism until the thread has finished its job before you can test your code’s results. This is tutorial #11 in our comprehensive Selenium tutorials series. assertTrue;. @Before and @After sandwiches each test method in the class. If you are lucky you may see an integration test or two. Introducing the Java 8 testing utilities. 11, it will create one instance and call the test-method, then create the next instance and call the test-method, etc, (which is better, of course, since it requires less total memory-resources). Spring4JUnit4Test. Unit testing is a type of software testing. > > Thanks for your reply. Step 5: Implement your testXxx() methods. As you see, we just have a stupid method which has 2 lines of code, we still could not cover it %100. also its has dependent operation. Overview of Java 8 support in Mockito framework, including Streams and default interface methods. Local unit tests only need these packages: org. By using ordinal() method, each enum constant index can be found, just like array index. Mockito & JUnit tests. Test; import junit. TestNG Assert methods will be the same as the Junit assertion methods that are discussed above. The JUnit testing framework is a popular choice among Java developers and has recently released a major version update with JUnit 5. Software developers are seeking ways to increase the quality of releases, in order to ensure that problems in the code are fixed before they become problems for their customers. The canonical reference for building a production grade API with Spring. It is very powerful and easy to use. mock(objectServiceImpl. Hi, I'm trying to write JUnit test but I'm having trouble with the following errors: "Test class not found in selected project" -> when running AClassTest. Vertx Unit is designed for writing asynchronous unit tests with a polyglot API and running these tests in the JVM. The tutorial Junit Mockito Verify method will show you how to verify a Java class method has been executed at least once or not. Getting Started with Mocking in Java using Mockito. Java actually provides ways to call private method with the help of reflection, java. Depending on a number of. test package and choose New->JUnit Test Case. 7 Testing with JUnit. JUnit is a simple framework to write repeatable tests. In this video I will show how to write JUnit test cases with mock objects using mockito framework. We will unit test the Business Service using Spring Boot, Mockito and JUnit in two different approaches. By default the Archetype10 will add these, but double-check the pom located at. NET (all languages), PL/SQL, Eiffel, Delphi, VB. 有关@override方法的junit测试用例 - junit test case about @override method 您应该如何为同一接口的多个实现编写junit测试用例? - How should you write junit test cases for multiple implementation of the same interface? 如何在java中编写测试用例 - how to write test case in java. * classes it "sees" to the system loader. Annotations are extremely important when creating JUnits. Using Mockito with JUnit. It is easy to understand, easy to integrate and the best thing is that it is open-sourced. Also, per simple experiments, in JUnit 3. To test your method you can check if the size of the list is decrease correctly by the size removed from the list. Actually, from there, I came to know about EasyMock and jMock frameworks and how useful they can be. I remember Chris Stevenson writing agiledox to pretty-print JUnit test names, which was one of the inspirations for BDD. 0 release for Java 8 makes testing exceptions much easier than before. JUnit is a framework for developing unit tests for Java classes. JUnit: A unit testing framework that is extensively used to test the code written in Java. Here is a skeleton which could be what you need. Don't be afraid of doing something trivial to make the test work. snmp = new Snmp(); } private void readTable() throws SnmpException. parallel testing of test cases for increased performance. Introduction. It also integrates with Selenium, Ruby on Rails, Watir and other web-based testing tools. Test RESTful Web Service with JUnit and Mockito Earlier I’ve published a blog post on now to create a RESTful Web Service(JAX-RS) to accept JSON payload with user profile details and how to save user profile details into a MySQL database using Java Hibernate framework. This library provides a kind of DSL for testing REST APIs. Testing using JUnit 5 is now available in Vert. With Mockito, you can test all of the above scenarios. Spring MVC Test Framework – To properly test the controller. Assuming we have two utility classes with static functions and one class for which we need to write unit test case. Every private method is always call in some of the public or accessible method directly or in directly. Example of JUnit test fixture. Mockito is a fantastic mock library for Java. EvoSuite: A test case generation tool that can automatically generate JUnit tests. Check out the complete version of HelloWorldTest for an example using Mockito and AssertJ. A Publisher sends messages to zero or more Subscribers. dependencies among test cases and TestNG also supports having the dataProvider and the test method in completely different classes, allowing for even better code reuse. Unit testing. how di check that? referencelettersbean rf = mockito. Spring Boot + JUnit 5 + Mockito. When you write a separate suite to execute the test cases in order, you might feel pain in the neck when you try to add every testXXX() method to the suite, esp. Test Reports in Java¶ If Selenium Test cases are developed using JUnit then JUnit Report can be used to generate test reports. Thanks so much for posting. Mockito is used to mock interfaces so that a dummy functionality can be added to a mock interface that can be used in unit testing. For junit 3 we will use our custom implementation of TestSuite class. methods in java are not very happy to accept void as the argument type! Effectively, in the above syntax the when method is taking void as one of the argument! Well this is a problem. There are several things to point out here. Validating tests using assertions – The key to writing a good test is validating the tests. By the way, if you are looking for any good book on JUnit and unit testing, you should look Pragmatic Unit Testing in Java with JUnit, it's an amazing book and teaches a lot about both JUnit and unit testing in Java. As far as Eclipse is concerned, the Spock test is handled in exactly the same way as a JUnit test would be. However, as far as JUnit is concerned the test succeeds with flashing lights and shooting ribbons. class) to initialize it. * DO use {{@Test}} annotation to highlight what methods represent your test cases * DO NOT put a JUnit 3. 8, ALL the test-class instances are created BEFORE all the test-methods are invoked, while in JUnit 4. Hi, Groups, I have written a java application, Now i want to test all the methods in the application using JUnit testing. run(ParentRunner. The integration test looks for the WSDL document, creates a service using the WSDL information, gets the port to the SOAP Web Service and then invokes the validate method. Note: It is good practice to store your unit tests in a different location than your application code. static int count = 0; // Use this to store an ID for each object. private void compare Set JUnit Test case fail. Create a new Java class (name it as JUnitTestReporter) that applies the JUnit rules with the help of the TestWatcher() class. I remember Chris Stevenson writing agiledox to pretty-print JUnit test names, which was one of the inspirations for BDD. You will apply on real projects and learn how to use these tools to automate manual test cases. Following are the most commonly used annotations and their usage in a basic unit test written in JUnit 4. Here is a unit test using JUnit 4. The first test testInitialize() behaves like any other Mockito test with the exception that we mock it using PowerMockito. I'm not sure if it is used correctly. We have looked at unit and integration tests using the JUnit framework for Java codebases, integrating JUnit in development and build environments, how to use mocks and stubs with suppliers and Mockito, common conventions and best code practices, what to test, and some of the other great JUnit features. I was overthinking adding Mockito to Android unit testing. As you see, we just have a stupid method which has 2 lines of code, we still could not cover it %100. Samplers perform the actual work of JMeter Junit test case for jdbc connection. findById() method with In future articles I will show how I handle difficult to test classes and also how Mockito can help in integration tests. valueOf() method returns the enum constant of the specified string value, if exists. A common use for JUnit is to create a set of unit tests that can be run automatically when changes are made to software; in this way, developers can ensure that changes to the software they are creating do not break things that were previously functioning. We can mock an object using @Mock annotation too. It's very convenient, its API is clear, usage is laconic. Hi, Groups, I have written a java application, Now i want to test all the methods in the application using JUnit testing. Each pattern you specify here will be used to create an include pattern formatted like **/${test}. This is how JUnit knows what to do with the processing section of code. java:498) at. In this video I will show how to write JUnit test cases with mock objects using mockito framework. OrderedTestSuite; import junit. Eclipse does most of the boring work for you. > Comma-separated list of names of test case methods to execute. [I have added a new Spring Boot Tutorial on this, please review give me feedback. (If one doesn't exist, see the section below about writing tests for a new class) If the test suite has not been converted to JUnit4 yet, one or more test methods can be added to the class using the JUnit conventions. Testing using Mockito. A JUnit test fixture is a Java object. When you use Serenity with JUnit, you need to use the SerenityRunner test runner. Use verify from Mockito to simply verify that the method was. Data access object unit test using Mokito framewor Testing servlets using JUNIT and MockIto; Implement Java Code Coverage and Junit test cases Implement FindBugs using ANT; Implement PMD and CPD (Copy paste detector) using Definition of equals and hashCode; Save properties (key, value -- pairs) in a ". @BeforeAll. How do I test static methods, and how do you test private methods. In general it it safe to ignore trivial code. In this blog, I will show, how we can test our void method using Mockito. Test; import org. The major difference between Junit and TestNG assertion methods come in the way of handling assertions. This book shows you how to make use of the power of JUnit 5 to write better software. Following is an example of how to use it (not an ideal usecase but just wanted to illustrate the basic usage). Eclipse supports creating test cases and running test suites, so it is easy to use for your Java applications. More Mocking with Mockito. arguments), which go inside the parentheses. JUnit - Assert if a property exists in a class. As far as Eclipse is concerned, the Spock test is handled in exactly the same way as a JUnit test would be. Asserts using Comparable. It has one problem: if both write and close throw exceptions, the second exception will be passed up the stack even though it is likely that the first was the root cause. Here is my test case: @Test public void testServlet() throws ServletException, IOException {. Conclusion. In particular, make sure that: the test class extends junit. Create a method for each test case and annotate it with @Test; Create a @Before method and initialize the Mockito library. JUnit instantiates the class during all of its test methods. class) annotation tells the test runner to run tests in this class. 0 was first released over a decade ago after the introduction of annotations in Java 5. methods in java are not very happy to accept void as the argument type! Effectively, in the above syntax the when method is taking void as one of the argument! Well this is a problem. Friday, June 20, 2014. The first test testInitialize() behaves like any other Mockito test with the exception that we mock it using PowerMockito. After that it executes the methods marked with the annotation After" in the main thread. To aid developers with their testing efforts, GWT provides integration with the popular JUnit unit testing framework and Emma code coverage tool. In all your JUnit test classes, make sure you do a static import of the Mockito library: import static org. If a test file is imported into jGRASP (i. TestNG provides more advanced assertion handling techniques such as dependent classes, Group Test, Parameterized tests etc. JUnit, which is well known to most Java developers at this point, is easily applied to many HBase applications. I can able to write the code to test the method which is having the return type such as Please give some samples and advice how to test the void methods With Regards Karthik. Mock a simple method using PowerMock. i am using verify() method and times to check how many times a method is called for a void method. Writing code like this can get repetitive, but there are tools to make it easier. Test-driven development (TDD) is a software development process that relies on the repetition of a very short development cycle: first the developer writes an (initially failing) automated test case that defines a desired improvement or new function, then produces the minimum amount of code to pass. } } JUnit tests are started using the JUnitCore class. runners; import custom. Class#getDeclaredMethods() is not consistent across runs. – agrawalankur Feb 5 '14 at 19:46 your first point merely advertises a tool, but it doesn't explain why you believe it is better than alternatives, such as eg testing private methods indirectly as was. Test; import junit. The requirements to create a test method are that it must be annotated with @Test, be public, take no arguments and return void. But sometimes we want to call it directly, for example in unit testing. But if I want to write the private method before its calling method, and I want to write the unit tests before writing the private method, I'm back to wanting to directly test the private method. Since we expect null passwords to fail, we’ll simply test our assumption using the assertFalse() test. Find the code of test case. Tests should hook into the existing junit framework. You can report feature requests and bugs in GitHub. This instruments the JUnit class and instantiates the WebDriver driver (if it is a web test), as well as any step libraries and page objects that you use in your test (more on these later). Each class inside the src/main/test folder will have all public methods with a @Test annotation automatically executed as a test. Methods marked with this annotation need to be defined as static to work with JUnit. Use verify from Mockito to simply verify that the method was. Below are the ways to write your customized classes. See: JUnit: testing exception with Java 8 and Lambda Expressions. 11, it will create one instance and call the test-method, then create the next instance and call the test-method, etc, (which is better, of course, since it requires less total memory-resources). Overview of Java 8 support in Mockito framework, including Streams and default interface methods. doThrow() if you want to throw an exception from the mocked void method. For junit 3 we will use our custom implementation of TestSuite class. According to JUnit website, JUnit is a simple framework to write repeatable tests. Test methods must be annotated by the @Test annotation. It’s useful when we want to use the mocked object at multiple places because we avoid calling mock() method multiple times. Thank you so much for posting, I’m a hybrid sysadmin/graphic designer/ui guy/programmer. You should be able to do it within 2 minutes. JUnit annotations. A common use for JUnit is to create a set of unit tests that can be run automatically when changes are made to software; in this way, developers can ensure that changes to the software they are creating do not break things that were previously functioning. You use an assert method, provided by JUnit or another assert framework, to check an expected result versus JUnit assumes that all test methods can be executed in an arbitrary order. Capable of testing Oracle, Informatica, SqlServer, PostGreSQL, MySQL, etc. ) If you would rather control which methods are called when running the tests (rather than using all methods starting with "test"), you can write a method to create a test suite. They are working fine but I'm not completely confident about the coverage. Its API is intended for use in both types of Android test, allowing the user in some cases to run the exact same test as both a local test on the JVM and as an instrumented test on an emulator or. timeout(int) method which could be. The testDesignedToFail() method demonstrates what a failed test case looks like in the JUnitEE framework. We have looked at unit and integration tests using the JUnit framework for Java codebases, integrating JUnit in development and build environments, how to use mocks and stubs with suppliers and Mockito, common conventions and best code practices, what to test, and some of the other great JUnit features. findById() method with In future articles I will show how I handle difficult to test classes and also how Mockito can help in integration tests. Void methods can be used with Mockito’s doNothing(), doThrow(), and doAnswer() methods, making mocking and verifying intuitive: However, doNothing() is Mockito’s default behavior for void methods. You can report feature requests and bugs in GitHub. For example, you have already seen a primitive type called an int. Home » Java » Mockito » Mockito Mock Void Method Most of the times Mockito when() method is good enough to mock an object’s behavior. > Gesendet: Sonntag, 12. While adding JUnit unit tests to one of the projects I've contributed to I've come across a SOAPHandler implementation The problem with SOAPHandler testing is the handleMessage() method uses a. Run a Java test with less overhead than integration tests and no need to deploy the service you're I will demonstrate how to write a JUnit unit test for such service -- without having to actually deploy it You can download it manually from the Mockito website, or if you use Maven/Ivy/Grape, just add it as. Now we need to create your own classes to test. JUnit 4 simplifies testing by using annotation feature provided by Java 5 rather than relying on subclassing Lets write the parameterized test case where we convert 1000 USD/UK/AUD/CAD into Indian Rupees. In test driven development(TDD) unit testing is a sub part which implies the quality of the implementation. Learn the basics of JUnit and Mockito. Sometimes when we test a call to a void method all we want to do is just make sure that at some point in its life cycle, another method will be called with certain parameters. The world of Java and testing has evolved a lot since then. A JUnit test class is just like a ordinary Java class, but with few annotations in it. Here is an example with Eclipse. esGateKeeper(test, "CSP" I convert app code from smali to java, but i don't know how to convert java to smali. 2) Add a setter to the rule object and inject the driver object in the rule. This tutorial demonstrate spring boot test service layer example. When writing unit test cases for a JSF application there might be a need to mock some of the FacesContext static methods. The keyword void means that the method main doesn’t return any data to whomever calls it (JRE in this case). Lets see how we can mock a static method using JUnit, Mockito and PowerMock. Therefore, you are writing junit test cases where your are forced to wait using method Thread. Let say that in your class you have an ArrayList named mMammals. I have a selenium project that has junit test cases. Since it’s the simplest way to write a file in Java, FileWriter is one of the most popular methods. January 19, 2016 By ksurendra. And what are they using it for? Even after 20 years of JUnit’s existence it is still mostly being used for unit tests. java template where you write your tests. Mockito Setup. We have looked at unit and integration tests using the JUnit framework for Java codebases, integrating JUnit in development and build environments, how to use mocks and stubs with suppliers and Mockito, common conventions and best code practices, what to test, and some of the other great JUnit features. When you write Junit test case for void method then you cannot return anything from your actual method test but at the same time you also don’t know whether your actual method has been executed or not. also its has dependent operation. To write additional tests for a class with existing tests, first locate the test class. In this case the name of the test case has to correspond to the test method to be run. Following are the most commonly used annotations and their usage in a basic unit test written in JUnit 4. JUnit annotations: @Test - Any method annotated with it is a test case. To learn more about the JUnit 5 extension model, have a look at this article. Local unit tests only need these packages: org. Also, per simple experiments, in JUnit 3. Out with the old. ) If you would rather control which methods are called when running the tests (rather than using all methods starting with "test"), you can write a method to create a test suite. The testDesignedToFail() method demonstrates what a failed test case looks like in the JUnitEE framework. If a test file is imported into jGRASP (i. Methods are nothing but members of a class that provide a service for an object or perform some business logic. Introducing the Java 8 testing utilities. In this post we will learn about using TestNG and Mockito together. Capable of testing Oracle, Informatica, SqlServer, PostGreSQL, MySQL, etc. Unit tests are written with JUnit, a common unit testing framework for Java. java MathApplication. I am unable to write easymock or expect for void methods. Writ-ing a JUnit test case is intentionally designed to be as easy as possible. The article presents quick code example for doing unit testing with JUnit & Mockito mocking framework. And then, we display the details of the student in two ways- one by using the printDetails() method and the other by using the get methods provided in the class. A test runner either expects a static method suite as the. x is increasingly popular for writing reactive applications on the JVM. MR Unit Provides a mock. Here is a skeleton which could be what you need. The TestWatcher JUNIT class allows overriding the failed() and succeeded() JUNIT methods that are called automatically when tests fail or pass. (Similarly, you can write a protected void tearDown() method to be called after each test. Static methods have their use. Step 14 - Tip - Repeat same test multiple times. ] In continuation of my earlier blogs on Introduction to Spring MVC and Testing DAO layer in Spring MVC, in this blog I will demonstrate how to test Service layer in Spring MVC. Write the test first.