Quick Answer: Can You Unit Test A Void Method?

What is J unit testing?

JUnit is a unit testing framework for the Java programming language.

JUnit has been important in the development of test-driven development, and is one of a family of unit testing frameworks which is collectively known as xUnit that originated with SUnit..

How do you call a void method in JUnit?

How to mock void methods with mockito – there are two options:doAnswer – If we want our mocked void method to do something (mock the behavior despite being void).doThrow – Then there is Mockito. doThrow() if you want to throw an exception from the mocked void method.

What are the features of J unit?

Features of JUnitJUnit is an open source framework, which is used for writing and running tests.Provides annotations to identify test methods.Provides assertions for testing expected results.Provides test runners for running tests.JUnit tests allow you to write codes faster, which increases quality.More items…

Do call real method Mockito?

Use Mockito’s thenCallRealMethod() to Call a Real Method With Mockito we can Mock an object, stub some of it’s methods but not the other and still be able to call a real method of this stubbed object.

How do you mock a void in EasyMock?

If we just want to mock void method and don’t want to perform any logic, we can simply use expectLastCall(). andVoid() right after calling void method on mocked object. You can checkout complete project and more EasyMock examples from our GitHub Repository.

What does Mockito verify do?

Mockito Verify methods are used to check that certain behavior happened. We can use Mockito verify methods at the end of the testing method code to make sure that specified methods are called.

What is Mockito spy?

A Mockito spy is a partial mock. We can mock a part of the object by stubbing few methods, while real method invocations will be used for the other. By saying so, we can conclude that calling a method on a spy will invoke the actual method, unless we explicitly stub the method, and therefore the term partial mock.

What does unit testing mean?

A unit test is a way of testing a unit – the smallest piece of code that can be logically isolated in a system. In most programming languages, that is a function, a subroutine, a method or property. The isolated part of the definition is important.

Can we write JUnit test cases for void methods?

Conclusion. In this example, we have learned that how we can JUnit Test Void Method. We have also learned that how to catch the exception if it is thrown by a void method. Actually testing mechanism is same for all methods, but void methods are special as we don’t have any returning value to be matched for testing.

How do you unit test a function that does not return anything?

2 AnswersIf your function is supposed to assert something and raise an error, give it wrong information and check if it does raise the right error.If your function takes an object and modifies it, test if the new state of your object is as expected.More items…•

How do you mock a static method?

There are four easy steps in setting up a test that mocks a static call:Use the PowerMock JUnit runner: @RunWith(PowerMockRunner. … Declare the test class that we’re mocking: … Tell PowerMock the name of the class that contains static methods: … Setup the expectations, telling PowerMock to expect a call to a static method:

Can we mock final class using Mockito?

You cannot mock a final class with Mockito, as you can’t do it by yourself. The disadvantage is that there is a lot of boilerplate code; the advantage is that you can add some methods that may relate to your application business (like the getInstance that is taking a user instead of an accessToken, in the above case).

Why we need JUnit test cases?

Junit is built on idea of “first testing and then coding” which helps us to increase productivity of test cases and stability of the code. It is open source testing framework allowing users to write and run test cases effectively. Provides various types of annotations to identify test methods.

Can you unit test void methods?

You might write a simple void method that takes some arguments, validates those arguments, then makes a call to insert that data into a database. To unit test the validation step, you might go ahead and mock the database, injecting it into your class with constructor DI of some sort.

How do you check if a method returns void?

Therefore, testing of these methods consists of these three steps:Set the object being tested to the initial state before calling the parameterless method.Call the parameterless method.Check the return value or the side effects of the parameterless method.

How do you mock a void method?

Mockito provides following methods that can be used to mock void methods. doAnswer() : We can use this to perform some operations when a mocked object method is called that is returning void. doThrow() : We can use doThrow() when we want to stub a void method that throws exception.

Do nothing when a method is called Mockito?

doNothing: Is the easiest of the list, basically it tells Mockito to do nothing when a method in a mock object is called. Sometimes used in void return methods or method that does not have side effects, or are not related to the unit testing you are doing.

How do you assert exceptions in JUnit?

When using JUnit 4, we can simply use the expected attribute of the @Test annotation to declare that we expect an exception to be thrown anywhere in the annotated test method. In this example, we’ve declared that we’re expecting our test code to result in a NullPointerException.

Why is Mockito used?

Mockito is a mocking framework, JAVA-based library that is used for effective unit testing of JAVA applications. 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.

What is stubbing in testing?

Stubbing, like mocking, means creating a stand-in, but a stub only mocks the behavior, but not the entire object. This is used when your implementation only interacts with a certain behavior of the object.