Mockito different answers Table of … Mockito doAnswer Method Read More » Mar 21, 2014 · Based on Java evaluation order, this makes sense: Mockito calls your answer as if it were the system under test calling your answer, because there's no way for Mockito to know that the call to mobileMethod immediately precedes a call to when. Jul 30, 2024 · Both methods let you decide what a mocked object returns. If the type is different, a matching method needs to be found on delegate type otherwise an exception is thrown. Jul 30, 2024 · In this example, the PaymentServiceTest class uses Mockito’s thenAnswer method with a custom Answer to simulate different responses based on the payment amount. Nov 9, 2024 · Mocks are objects with predefined answers to method calls, which also have expectations for executions. In rare scenarios mockito - how to mock different behaviors for different argumentsI want a simple mock to behave one way when called Aug 11, 2020 · Example Project Dependencies and Technologies Used: mockito-core 3. 3. Mockito providers different way to mock methods, like do…when and when. Sep 30, 2025 · Mockito is an open-source and widely used mocking framework for Java applications. It hasn't gotten there yet. May 8, 2016 · In order to do it right and with minimal code you have to use the ArgumentMatcher, lambda expression & don't forget to do a null check on the filters members in the ArgumentMatcher lambda (especially if you have more than one mock with the same ArgumentMatcher). May 11, 2024 · In this quick tutorial, we’ll learn about the Mockito UnnecessaryStubbingException. An answer that directly forwards the calls to the delegate. This exception is a common exception we’ll likely encounter when using stubs incorrectly. Customized argument matcher: private ArgumentMatcher<Request> matchRequestId(final String target) { return request -> request != null Jun 26, 2024 · Mockito allows developers to stub methods to return specific values or perform certain actions. To answer this question, you need to have at least 10 reputation on this site (not counting the association bonus). Feb 20, 2015 · Not clear what you're asking: the title says "different answers for different matchers", the question says " multiple answers on a single invocation". This will help you to crack any Mockito Mocking Framework interview successfully. Learn how to use Mockito. Once you accept an answer, most people won't bother supplying a different one. Jan 16, 2024 · Typically, Mockito comes with a set of ready-to-use generic interfaces that we can use to configure a mock’s answer. when method multiple times on the same object with expert tips, code examples, and debugging advice. In this guide, we'll explore how to invoke Method B automatically whenever Method A is called in your test scenarios using Mockito. In this tutorial, we’ll see how we can test a user role-based authentication service using Mockito based on different roles with the help of the Answer API provided by Mockito. The Answer interface enables us to define custom return values and org. 5. Answer Mockito is a powerful mocking framework that simplifies unit testing in Java. Some interesting answers can be found in org. Feb 7, 2025 · Compare Mockito EasyMock and JMockit for unit testing in Java. g. Useful for spies or partial mocks of objects that are difficult to mock or spy using the usual spy API. Aug 24, 2010 · If the verified method called 2+ times, mockito passes all the called combinations to each verifier. For example, instead of iterators one could use Iterable or simply collections. Overview In this tutorial, we’ll see how to mock nested method calls using Mockito stubs, specifically deep stubs. To some degree I agree that, for your concrete use case, it may be more appropriate to mock the DB lookup. Allows mock creation with additional mock settings. Oct 29, 2017 · As with other articles focused on the Mockito framework (such as Mockito Verify, Mockito When/Then, and Mockito’s Mock Methods), the MyList class shown below will be used as the collaborator in test cases. In Mockito we can mock methods in 2 different ways, Using when-then Mockito provides a versatile way to handle method invocations with its doAnswer () method. Learn about their ease of use, flexibility, performance 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). In conclusion, the Mockito Answer API offers a powerful way to make your tests smarter. For example, it provides Answer1<T,A0> for a single argument invocation. This guide will help you understand the correct way to use this feature to test different return values for successive calls. answers package. stubbing Interface Answer<T> Type Parameters: T - the type to return. For what it's worth, I believe there is a better way of doing this - I might post an answer later. Original version of Mockito did not have this feature to promote simple mocking. This guide will help you understand how to mimic multiple invocations of a method successfully using Mockito. thenReturn() returns a fixed value while thenAnswer() lets you use the parameters to determine a return value. Learn Mocking Framework for Mocking in Unit Testing. Feb 18, 2023 · I want to know what Mockito is. 4 Using multiple thenReturn statements in Mockito can sometimes lead to unexpected behavior if not implemented correctly. Oct 18, 2021 · 3 thenReturn, as the name says, just returns some value when the mocked condition occurs. The Mockito. So mockito expects your verifier silently returns true for one of the argument set, and false (no assert exceptions) for other valid calls. While these methods may look similar at first glance, each serves a slightly different purpose. Mockito only executes the first match. removeAt(0) without the lambda method returns the same answer on all of them In this example Invocation is not used and checks only 2 consecutive calls. Simple Mocking Nov 7, 2014 · Making good use of Spies in Mockito, and how spies are different from mocks. Apr 1, 2025 · Learn mocking with Mockito - A comprehensive Mockito Tutorial for beginners with code examples. 概述 Mockito 是一个广泛使用的 Java 应用程序单元测试框架。它提供了各种API来模拟对象的行为。在这个教程中，我们将探讨如何使用 doAnswer() 和 thenReturn() 的桩插件技术，并进行比较。 这两种API都可以用于方法的桩插件或模拟，但在某些情况下，我们只能选择其中一个。 Nov 26, 2021 · Writing unit test is very important for better software quality. Previously they were considered unmockable, preventing the user from Consider a method signature like: public String myFunction(String abc); Can Mockito help return the same string that the method received? Jan 8, 2024 · Providing a Different Default Answer Now that we understand a bit more about mock settings, let’s see seeing how we can change the default return value for a mock object. Those offer natural ways of stubbing (e. We will see all the differences in detail. doAnswer() method provides a dynamic way to define custom behavior for mock object methods. The Answer Interface Let's start by investigating the Answer interface. Our ambition is that Mockito "just works" with final classes and methods. May 16, 2025 · Mockito allows you to do this by stubbing methods using thenReturn and thenAnswer. Answer Mockito provides a powerful framework for creating mock objects in Java. . Overview In this tutorial, we'll explore different ways to return custom values from mocked methods. 2. This helps in writing clean, maintainable, and reliable unit tests May 11, 2024 · This cookbook shows how to use Mockito to configure behavior in a variety of examples and use cases. To learn more about testing with Mockito, check out our comprehensive Mockito series. Most of the time we face the question to use when-then vs do-when. Can anyone help me in detail? So far, I have tried it with thenReturn. Consider writing simple tests that use simple mocks. Typical use case could be mocking iterators. If you cannot write a test in a simple way - refactor the code under test. For unit tests Mockito is one of the most common choices of developers. It offers methods like doAnswer, doReturn, and doThrow, each with unique use cases and behaviors. It requires changing how you think about your unit tests while removing a lot of boilerplate. When a method is invoked multiple times with different parameters, you can set up stubbing for each unique call. The reputation requirement helps protect this question from spam and non-answer activity. In this tutorial, we’ll explore different ways to introduce such delays using Mockito. By allowing methods to return different results based on their input, you're not just writing tests—you're crafting user experiences. The format of the cookbook is example focused and practical — no extraneous details and explanations are necessary. using real collections). Mar 24, 2024 · Mockito provides two similar approaches for stubbing behaviour on a mock: the when method and the do* family of methods. In some test scenarios, we may need to introduce a delay in the response of a stubbed method to simulate real-world conditions, such as network latency or slow database queries. junit 4. HTTP clients) with Mockito deep stubs. Sep 4, 2025 · Mockito Interview Questions and answers with sample code examples. Jan 2, 2025 · Unlock the secrets of Mockito's when-then and do-when! Discover when to use each and transform your unit testing strategy—your code's future depends on it! Enumeration of pre-configured mock answers You can use it to pass extra parameters to @Mock annotation, see more info here: Mock Example: @Mock(answer = RETURNS_DEEP_STUBS) UserProvider userProvider; This is not the full list of Answers available in Mockito. Enumeration of pre-configured mock answers You can use it to pass extra parameters to @Mock annotation, see more info here: Mock Example: @Mock (answer = RETURNS_DEEP_STUBS) UserProvider userProvider; This is not the full list of Answers available in Mockito. 13: JUnit is a unit testing framework for Java, created by Erich Gamma and Kent Beck. 1. Feb 17, 2024 · Mockito is a Java framework used for creating and working with mock objects in tests. Following is an example of how to use it (not an ideal usecase but just wanted to illustrate the basic usage). Learn how to fix the Unfinished Stubbing Exception in Mockito tests with this detailed guide, including common mistakes and solutions. Mar 26, 2024 · In the following example we use chained method calls using thenReturn and we use thenAnwer to support multiple calls to our mocked method temperature that returns a Stream of Double values: Learn how to make Mockito mocks perform different actions sequentially using Answer or thenAnswer methods effectively. then. From the docs: Sometimes we need to stub with different return value/exception for the same method call. 11 Apr 28, 2021 · Reduce the boilerplate stubbing setup for mocking a chained method call of a fluent APIs (e. And of course, if you want to learn more about testing well with Mockito, have a look at the other Mockito articles here. stubbing. Examples of mock settings: //Creates mock with different default answer & name Foo mock = mock(Foo. May 17, 2024 · The Mockito framework provides many stubbing/mocking techniques such as doAnswer (), doReturn (), thenReturn (), thenAnswer (), and many more to facilitate various types and styles of Java code and its testing. JDK 8 Maven 3. thenAnswer invokes the answer method of an Answer instance, and allows you to execute some arbitrary code when the condition occurs. Dec 13, 2024 · The answer = Answers. I am confused when to use doAnswer vs thenReturn. We’ll add a new method for this tutorial: public class MyList extends AbstractList <String> { @Override public void add(int index, String element) { // no-op } } Copy 2. Is it supporting JUnit or is it an environment for writing JUnit test cases? Can someone please explain to me the differences between JUnit and Mockito? Oct 19, 2024 · 1. class mockito-core junit-jupiter mockito-all mockito-android mockito-bom mockito-core mockito-errorprone mockito-inline mockito-junit-jupiter mockito-scala-cats_2. With doAnswer (), you can define custom behavior for a mocked method, allowing more flexibility compared to simple stubbing. doThrow() if you want to throw an exception from the mocked void method. Feb 20, 2013 · Partial mocking using Mockito's spy method could be the solution to your problem, as already stated in the answers above. RETURNS_DEEP_STUBS part specifies that Mockito should automatically return mock objects for any method calls on nested objects, allowing deep stubbing. Jun 19, 2019 · Java Mockito: How to prepare different answers Asked 5 years, 6 months ago Modified 5 years, 6 months ago Viewed 41 times Oct 23, 2021 · // Calling answers. A common challenge developers face is how to handle multiple calls to the same method with identical arguments on a mock object. Gain insights into potential questions… Learn how to customize the default answers of a Mockito mock in your tests for improved behavior and control. Feb 20, 2022 · Use mockito to mock calls made to the constructor and return a mock. Then we’ll take a look at exactly what this exception means, and under what circumstances it can occur May 17, 2024 · 1. Nov 11, 2011 · This answer helped me a lot because doAnswer() / thenAnswer() do not allow chaining multiple calls as doReturn() / thenReturn() do and I needed to compute something and not just return a different value. The delegate may or may not be of the same type as the mock. This is a fantastic improvement that demonstrates Mockito's everlasting quest for improving testing experience. 3: Mockito mock objects library core API and implementation. Throughout the article, we'll cover different use cases and different Answer implementations. This allows you to specify custom behavior when the void method is called. Creating an anonymous Answer object with a private count variable was what did the trick for me. This article explains how to mock a method with varying parameters, including the use of argument matchers like `any ()` to simplify your tests. We’ll start by explaining the philosophy behind strict stubbing, and why Mockito encourages its use by default. Jul 30, 2024 · The doAnswer method in Mockito is used to stub a void method with a generic answer. Don't use it too often. Repeat after me: simple tests push simple, KISSy, readable & maintainable code. doThrow - Then there is Mockito. It allows developers to create mock objects, simulated objects that mimic the behavior of real ones in a controlled way. Handling multiple calls to the same method can be challenging, especially when different return values are needed for each call. The Answer interface provides a way to define this behavior by implementing the answer method, which gets invoked when the stubbed method is called. mockito. Explaining the Problem In complex code, especially legacy code, it’s sometimes hard to initialize all the objects needed to unit test. Using Mockito is not just a matter of adding another dependency. For this purpose, Mockito provides the Answer interface. May 29, 2024 · Mocking is an essential technique in software testing, particularly when working with Java and frameworks like Mockito. This comes in handy when you need to perform specific actions upon a method call or when the method's behavior depends on its Mockito is a powerful framework for testing in Java that allows developers to write unit tests by creating mock objects, verifying behaviors, and stubbing method calls. Learn how to effectively use Mockito's DoAnswer and ThenReturn methods for advanced mocking techniques in Java testing. Mockito now offers an Incubating, optional support for mocking final classes and methods. May 15, 2020 · Interested to learn about thenReturn? Check our article explaining how to use thenReturn() and thenAnswer() methods of Mockito. Mar 12, 2014 · If you want something better to be suggested, you shouldn't have accepted an answer. All Known Implementing Classes: Answers public interface Answer<T> Apr 14, 2016 · I am using Mockito for service later unit testing. By replacing real dependencies with mocks, Mockito enables testing code in isolation, without actually invoking real methods. In this article, we cover multiple mock interfaces, listening invocations, matchers, and argument captors, and see firsthand how Mockito makes your tests cleaner and easier to understand. Understanding the Need for Apr 29, 2025 · Prepare for your next interview with our comprehensive guide on Mockito Interview questions and answers. Most stubs in Mockito are written with when at the beginning of the line, following the format “ when the method is called then return something”. fno rzxznkrl fdsska jgtaq opswa bezokn wlff emkxjv kerh smcrif gneko dnwwh hgvqv xbzhhtnw epwkd