Mockito Spy Class With Constructor Arguments

A spy is always based on a real object. The previous example mocked a class with hardcoded argument. Mockito has its own test runner implementation that allows you to reduce boilerplate in order to create test doubles (mocks and spies) and to inject them (either via constructors, setters, or reflection) into the defined object. Introduction to Mockito Framework & its usage. MissingMethodInvocationException is RuntimeException and subclass of MockitoException. Doing that relaces all the methods by methods doing nothing, and returning default values. For Mockito, there is no direct support to mock private and static methods. public static MockitoException wrongTypeOfReturnValue(String expectedType, String actualType, String methodName) { return new WrongTypeOfReturnValue(join. txt) or view presentation slides online. @InjectMocks creates an instance of the class and injects the mocks that are created with the @Mock (or @Spy) annotations into this instance. This is perfect for exposing a complex object that never changes over time without writing a StatefulWidget. Mockito verifies argument values by using an equals() method With Mockito you can spy a real class. The below example will show you how to mock an Autowired @Value field in Spring with Junit Mockito. If you already read some other blog post about unusual mocking, you can skip prelude via this link. Spying Using Mockito’s spy feature, we can mock only those methods of a real object that we want to, thus retaining the rest of the original behavior. 0, faking of Spring Beans is supported natively via annotation @MockBean. NagRock / ts-mockito. anyLong etc. The reason is it guarantees real methods are called against correctly constructed object because you're responsible for constructing the object passed to spy() method. This is perfect for exposing a complex object that never changes over time without writing a StatefulWidget. EDIT: As of Spring Boot 1. In the how-to series today I will show how-to mock constructors using PowerMocks - Mocks on Steroids!. Mockito - Verifying Behavior - Mockito can ensure whether a mock method is being called with reequired arguments or not. This post Is just little miscellaneous where I will show you how to mock and verify a void method call. Hence the Mockito side now can take the extra. Using Mockito greatly simplifies the development of tests for classes with external dependencies. Mockito 中文文档 ( 2. 5/3 mm Size 12. Mockito Spy Three ways to mock an object using Mockito Using Mockito @InjectMocks with Constructor and Field Injections Void methods and Mockito in Java Find out if an object is a mock or spy in Mockito Execute Tests in Order in JUnit 4 Mock methods that return void JUnit 4 - Run Test Method More than Once Group JUnit Test Cases using @Suite. initMocks(this) to initialise these mocks and inject them. public MockitoPostProcessor(Set definitions) Create a new MockitoPostProcessor instance with the given initial definitions. There is an annotation that you might find useful: @Captor. with Mockito Exception-when() requires an argument which has to be a method call on a mock to the real static classes, and you do not test those. In order for the test to run successfully, this Android dependency must be mocked. Note that you must use @RunWith(MockitoJUnitRunner. Field;--import org. onCommand turns parameter 1 into a long and the UUID into an OfflinePlayer. Not only can we do this, it is encouraged. Injecting a test implementation is helpful, but you will probably also want to test whether the class constructor and methods are called with the correct parameters. Writing Great Unit Tests distinguishes Good Programmers from Great Programmers. Mockito also supports the creation of mock objects based on the @Mock annotation. when (instance). Alternatively, if you don't provide the instance Mockito will try to find zero argument constructor (even private) and create an instance for you. Then add a constructor that get’s the expected element and implement the matches() method so it checks if the list contains that. Mockito verifies argument values in natural java style: by using an equals() method. But this case is different, since the interaction consists of invoking a constructor of the class to be mocked. As promised in the first part of the "Effective Mockito" blog series, I will concentrate on Mockito specifics in the followup posts. If you are new to unit testing with JUnit, please check out the previous post on How to write great unit tests with JUnit. whenNew() method. The other day, whilst writing tests with SinonJS I realised that there was no obvious way of mocking calls to class constructors in Javascript. mock() 과 같이 class 이름을 계속 붙여주어야 한다. Let's just say that I have a value object class "Foo" that doesn't have simple constructors (it has an all-args constructor and contains objects that also need all-args constructors). All the example code for this post is available at this gist. It might need to interact with a database, communicate with a mail server, or talk to a web service or a message queue. spy around it and created a PersonController class with it. Android & Mockito During the day I'm a mild mannered (debatable) Java developer currently paid to work on a multi-threaded server with it's own RCP client. In your class that is under test, you may have some private fields that are not accessible even through constructor. Mockito: No to Static Methods. Mockito cannot test static classes. line 6: invoke the method to be tested; The main drawback of this solution is that Mockito. When Mockito creates a mock – it does so from the Class of a Type, not from an actual instance. APPENDIX A: MOCKITO UNIT TESTING TUTORIAL This appendix is a tutorial over how to implement Mockito Unit testing/mocking framework. What i tried so far is the following :. Taking advantage of advanced mocks configuration. To test A in isolation, you can mock B so that while creating real instance of A, mock object of B will be injected into A instance. 12) Mockito 說明 useful when the argument to capture is a nasty. You don't hear about EasyMock much any more, and Mockito seems to have replaced it in mindshare. pdf), Text File (. Properties are injected even if private is applied. mock manually. Mockito verifies argument values in natural java style: by using an equals() method. class) or Mockito. Because Mockito checks all the arguments passed to the mock’s Java methods, the verification fails, since the last argument from the invocation does not match that from the verification. Mockito - Spying - Mockito provides option to create spy on real objects. In this tutorial, we will understand the importance of code coverage and how can we setup the Sonar + JaCoCo + Maven to get the code coverage. 呼び出し順序の妥当性検証 余計なメソッド呼び出しが行われていないことを検証する Mockito のアノテーション 複数回のモックメソッド呼び出しの結果を変化させる コールバック付きの戻り値定義 voidメソッドの振舞を定義するdoXXファミリー 実オブジェクトの動作を変えるspy 本記事は、以下の. class) annotation to use the Mockito test runner. Well Mockito (1. It’s important to realise that each type of test double has a different. JACADI Girl's Aucun Water Blue Cute Button Down Cardigan Sz 6 Months NWT,NEW BRABANTIA WASTE BIN SORT AND GO 16L TRASH GARBAGE WASTE BASKET HOME OFFICE,Axinite 3. Verify a method was called with certain argument using Mockito. Verify-mocks, stubs and dummies are created via the @Mock annotation @Mock private OrdersDAO. OK, I Understand. The command's arguments would be the Long ID and the player's UUID. How to mock a class with no parameter-less constructor. Alternatively, for complex objects, most providers expose a constructor that takes a function to create the value. InjectMocksScanner Create a new InjectMocksScanner for the given clazz on the given instance. The following java examples will help you to understand the usage of org. Mockito gives you a possibility of providing different answers for your mocks. spy() is a recommended way of creating partial mocks. spy() is used when you want the real code of the class you are spying on to do its job, but be able to intercept method calls and return values. mockitoSession() but adds the ability to mock static methods calls via StaticMockitoSessionBuilder. Possible reasons are static or final methods/classes (Mockito can't mock these) or access to Jenkins. Mockito with PowerMock - Tutorial on Mocking final and static methods Using PowerMock and Mockito to mock a constructor. Mockito verifies argument values in natural java style: by using an equals() method. Maybe some tips are not consider as the best practices by the Spring Boot, Mockito, EasyMock and/or TDD folllowers but for me and my team they are so useful when we write and run the Unit Test for medium or high complexity classes. Alternatively, if you don't provide the instance Mockito will try to find zero argument constructor (even private) and create an instance for you. 3 release and promised the following day I would post details on the @Spy annotation. Both tests should pass with mockito 1. marcocattaneo. hope that saves some times Original Class :. class or Class. Mockito JUnit Runner triggers UnnecessaryStubbingException only when none of the test methods use the stubbings. Wrapper Methods. mockito spy constructor (4) Without Using Powermock See the example below based on Ben Glasser answer since it took me some time to figure it out. If you want to do that, you'll need a spy, or a partial mock. 4GHz T-FHSS mit R304SB 4-Kanal Fernsteuerung - P-CB4GRS,. mock manually. initMocks() 또는 @RunWith(MockitoJUnitRunner. When you work with legacy codebase, sometime you would like to avoid the call to super constructor and super methods so that you can focus on covering sub class. For Mockito, there is no direct support to mock private and static methods. Properties are injected even if private is applied. mockStatic(Class), StaticMockitoSessionBuilder. spy(Object) to find out more about partial mocks. doXXX when 은 spy 와 함께 사용할 때. constructor. initMocks(this) method call or annotate your class with the @RunWith(MockitoJUnitRunner. Code Index Add Codota to your IDE (free). Out of the box, Mockito cannot mock final classes and final or static methods, but if you really need it, Mockito 2 provides the experimental MockMaker plugin. Mocking Void Methods. ) of class org. The dependency in that class is injected using mock object. a different instance of otherwise “normal” URI class. The bytecode manipulation has to be done at runtime to mock such methods. ) In case of my contructor I need to pass the parameter to the constructor of Mock class: var myMock = new Mock < ClassToTest >(MockBehavior. Check the lookupType parameter for customization. In the previous tutorial we saw how to use the p-namespace to configure bean definition. I'd like to test an abstract class. initMocks(this); }. The subtitle of Sujoy Acharya's Mockito Essentials (Packt Publishing, October 2014) is: "A practical guide to get you up and running with unit testing using Mockito. For example, if a suitable constructor is found, neither the setter injection nor the field injection will come to play. To create a spy, you need to call Mockito's static method spy() and pass it an instance to spy on. When using @Spy, mockito creates a real instance of the class and track every interactions with it. Tips & Tricks. MockitoSugar import org. configuration. This is perfect for exposing a complex object that never changes over time without writing a StatefulWidget. with Mockito Exception-when() requires an argument which has to be a method call on a mock to the real static classes, and you do not test those. 02205 1 72 Mitsubishi Ki67 Type 4 Heavy Bomber Hiryu, About. and Mockito to. While Mockito can help with test case writing, there are certain things it cannot do viz:. And finally if you want the constructor to be called you should use spy instead of mock. Best Java code snippets using org. The most common operation you will do in tests is the instantiation of object graphs. 2016-05-01: PowerMock 1. This article will demonstrate some scenario when we use whenNew and some gotchas I encountered along the way. withArguments() method allows to specify arguments, for each we want to override normal constructor calls. To my knowledge, you can't mock constructors with mockito, only methods. 0, powermockito 1. "Strict stubbing" feature in Mockito is available since early 2. You don't need to provide the mocks as arguments of the constructor. Add gradle dependency dependencies {… testCompile ‘org. This is where the difficulty lies, since Mockito cannot mock constructors. You can use methods like anyInt() of class org. creation; -import java. First we create a class called ListContains that implements the ArgumentMatcher interface. Mockito has decided to no corrupt an object if it has a parametered constructor. Showing 1-16 of 16 messages. NagRock / ts-mockito. Check the lookupType parameter for customization. The real class is represents a connection to a remote service. Another case is where MyClass uses getClass() somewhere, and requires the resulting value to be MyClass. Mockito is an open-source Mocking framework in Java. Another common pattern is to use test data builders to create the values that you need. Constructor injection; the biggest constructor is chosen, then arguments are resolved with mocks declared in the test only. This tutorial should help you learn how to create unit tests with Mockito as well as how to use its APIs in a simple and intuitive way. Using Mockito greatly simplifies the development of tests for classes with external dependencies. Cylinder Hand Held Vacuum Pump Handle Brass Brake Bleeder Kit Cars Motorcycles,MAURITIUS 15 DOLLARS P S123 1839 BUILDING SHIP RARE BANK NOTE CURRENCY MONEY,The Iron Dome Medal 2012 - 50mm Bronze Medals Collectible Gift Commemorative. mockitoSession() but adds the ability to mock static methods calls via StaticMockitoSessionBuilder. 3 release and promised the following day I would post details on the @Spy annotation. class) or Mockito. André Wegmüller gave me following tipp: I should check when the search for field inner is made. Learn Unit Testing with Junit & Mockito in 30 Steps Udemy Download Free Tutorial Video - Learn Mockito and JUnit - the most popular unit testing and mocking frameworks - with 25 Example. I was asked to put together examples how to mock Java constructs well know for their testability issues:. ABRSM is committed to supporting high-quality music-making, learning and development throughout the world, and to producing the best possible resources for music teachers and students. We will unit test the Business Service using Spring Boot, Mockito and JUnit in two different approaches. Additionally, it makes it possible to stub specific methods but leaves the other ones as they were. Basically, you annotate a method with @Cacheable and next time you call it with the same arguments, you get the cached value avoiding re-executing the method's code. An example of behavior verification + argument capture with Mockito (on TestNG) - Email. The reason is it guarantees real methods are called against correctly constructed object because you're responsible for constructing the object passed to spy() method. In certain scenarios like if we have no control or handle of argument passed into a mock we can use Mockito ArgumentCaptor to verify if certain arguments where passed to mocks. spy() is a recommended way of creating partial mocks. Mockito has its own test runner implementation that allows you to reduce boilerplate in order to create test doubles (mocks and spies) and to inject them (either via constructors, setters, or reflection) into the defined object. The provider will call that function only once, when inserting the widget in the tree, and expose the result. withParameterTypes() method is optional, but it is required here, since File constructor is overloaded. For example, if a suitable constructor is found, neither the setter injection nor the field injection will come to play. The dependency in that class is injected using mock object. java method Using Mockito to test abstract classes. As per Mockito you can create mock object by either using @Mock or Mockito. In my previous post we saw how can we write unit-tests for mocking final methods and classes. Conclusion and Limitations of Mockito. anyString, Mockito. Generally speaking, you can only mock a method which exists against an object. Mockito - Verifying Behavior - Mockito can ensure whether a mock method is being called with reequired arguments or not. hope that saves some times Original Class :. java: Works as is. Above lines mocks getAddressDetails() method which is database operation which we have successfully avoided using Mockito. Another case is where MyClass uses getClass() somewhere, and requires the resulting value to be MyClass. Mockito allows us to create mock objects. 0) This needs to be somewhere in the. Use it to capture argument values for further assertions. Can I do this using a mocking framework (I'm using Mockito) instead of hand-crafting my mock? How? The advantage of this resolution is that you do not have to implement the abstract methods, as long. initMocks(this) to initialise these mocks and inject them. Mockito with PowerMock - Tutorial on Mocking final and static methods Using PowerMock and Mockito to mock a constructor. First we create a class called ListContains that implements the ArgumentMatcher interface. spy(Object) to find out more about partial mocks. The real class is represents a connection to a remote service. Let's say we have two classes, BookDao and BookRepository. Copy the MockitoAfterTestNGMethod, MockitoBeforeTestNGMethod, and MockitoTestNGListener classes to your codebase from Mockito's TestNG subproject. Constructors for injection are selected from the biggest number of arguments to lowest. Unit tests should be small tests (atomic), lightweight, and fast. Above lines mocks getAddressDetails() method which is database operation which we have successfully avoided using Mockito. mocking List class : Multiple return values, Argument Matchers and. PowerMockito. This allows to capture these. To automatically prepare and assign mocks a metadata Mock should be placed over a public field of your test class. You can vote up the examples you like and your votes will be used in our system to generate more good examples. If the object is successfully created with the constructor, then Mockito won't try the other strategies. class);, I got NullpointerException because of using @RunWith(PowerMockRunner. configuration. Mockito Tutorial : Learn mocking with 25 Junit Examples and Mockito to mock a constructor. With a spy: @Test public void shouldReturn2Hours() { Float expectedHours = 2f; WorkChronometer workChronometer = new. Alternatively, for complex objects, most providers expose a constructor that takes a function to create the value. This is perfect for exposing a complex object that never changes over time without writing a StatefulWidget. Whenever your class needs a new dependency you’re forced to add it to the constructor’s parameters. Additionally, it makes it possible to stub specific methods but leaves the other ones as they were. Mockito works to streamline the delivery of these external dependencies that are incidental to the test. public class Test{ //Instance for spying is created by calling constructor explicitly: @Spy Foo spyOnFoo = new Foo("argument"); //Instance for spying is created by mockito via reflection (only default constructors supported): @Spy Bar spyOnBar; @Before public void init(){ MockitoAnnotations. So if we were curious about knowing more precisely about that object, what we would have to do is to spy on it. Injecting a test implementation is helpful, but you will probably also want to test whether the class constructor and methods are called with the correct parameters. Cylinder Hand Held Vacuum Pump Handle Brass Brake Bleeder Kit Cars Motorcycles,MAURITIUS 15 DOLLARS P S123 1839 BUILDING SHIP RARE BANK NOTE CURRENCY MONEY,The Iron Dome Medal 2012 - 50mm Bronze Medals Collectible Gift Commemorative. public static MockitoException wrongTypeOfReturnValue(String expectedType, String actualType, String methodName) { return new WrongTypeOfReturnValue(join. When you work with legacy codebase, sometime you would like to avoid the call to super constructor and super methods so that you can focus on covering sub class. However, we can use PowerMock along with Mockito framework to mock…. APPENDIX A: MOCKITO UNIT TESTING TUTORIAL This appendix is a tutorial over how to implement Mockito Unit testing/mocking framework. lets say for example, I have a list of user email ids, then i am calling a service to find out list of subscribed and unsubscribed users, so the response from the service will contain two. Argument matching with Mockito I recently fielded a question at a client about how to state verify indirect inputs into a mocked dependency. //Notice that we have to pass an actual instance of the EmployeeService class. githubmockitosample. But according to the wiki on the Mockito google code page there is a way to mock the constructor behavior by creating a method in your class which return a new instance of that class. Having said that, sometimes you run into legacy code you just have to work with and aren't able to refactor due to circumstances. mocking List class : Multiple return values, Argument Matchers and. junit - How do I mock any arguments to a private method using PowerMockito? I'm using Mockito 1. Mocking frameworks, such as Mockito, are powerful tools for testing and test-driven development (TDD) in particular. Package org. Tests using mocks can be written very readable. Since Activities and Fragments are created by the Android framework, which means that we can’t pass arguments to the constructors of these classes, with the use of factory methods, we can encapsulate the creation code inside the actual class that we are instantiating, so that on the creation site we don’t have to worry about the extras. It then puts that link in the HashBiMap. In this particular example, I'm testing a PricingServiceImpl class and it has a dependency to a DataAccess type. JUnit & Mockito, first steps 1. Mockito verifies argument values by using an equals() method With Mockito you can spy a real class. This is also the recommended way of matching arguments because it makes tests clean & simple. However, there is no support for constructor parameters. It caught me off guard when the question was asked (the question came first thing in the morning on an iteration planning day), so I didn't just rattle off an answer. Both tests should pass with mockito 1. See also javadoc Mockito. Mockito Framework - Free download as Powerpoint Presentation (. This won't work, because the class of a spy is actually a Mockito-generated subclass of the original class. When I browse through other people’s (or even my own) test code, I sometimes see a construct like. Use it to capture argument values for further assertions. A quick search for "mocking Javascript class constructor" did lead me to some helpful answers. Mockito spy verify. In the how-to series today I will show how-to mock constructors using PowerMocks - Mocks on Steroids!. @InjectMocks creates an instance of the class and injects the mocks that are created with the @Mock (or @Spy) annotations into this instance. You create an object instance calling one of its constructors and you tell Mockito that you are willing to change some methods for this instance :. Mockito is a powerful mock/stub library for unit tests in Java. Setter Methods Based – When a Constructor is not there, Mockito tries to inject using property setters. The following is a refresher with quick mockito basics for anyone who wishes to go through them. initMocks(this) to initialise these mocks and inject them. Showing 1-16 of 16 messages. the reason is when. Writing Great Unit Tests distinguishes Good Programmers from Great Programmers. It turns out that when using @InjectMocks annotation, Mockito injects mocks only to the constructor, leaving the fields undefined. You can use argThat(str -> str. I was asked to put together examples of how to mock Java constructs well know for. These examples are extracted from open source projects. a different instance of otherwise “normal” URI class. The mock API invocation goes into when() which is a static Mockito API method and the value that we want the want the mock to return goes into the then() API. You may also go ahead check whether some method is used at least X times by using Mockito. spy(Object) to find out more about partial mocks. This is important because I've started to pick up some habits from that team. The c-namespace allows you to configure the constructor arguments with inline arguments rather than nested constructor-arg elements. July 8, 2014 - Last update: May 8, 2018 - Programming, Unit test are important part of every application. Mock 测试是单元测试的重要方法之一。本文介绍了基于 Java 语言的 Mock 测试框架 - Mockito 的使用。什么是 Mock 测试Mock 测试就是在测试过程中,对于某些不容易构造(如 HttpServletRequest 必须在Servlet 容器中才能构造出来)或者不容易获取比较复杂的对象(如. ABRSM is committed to supporting high-quality music-making, learning and development throughout the world, and to producing the best possible resources for music teachers and students. Simple verify method:. But sometimes, it can be a little confusing to decide what to mock and how to mock. About a year ago, I wrote a blog post how to mock Spring Bean. spy() is used when you want the real code of the class you are spying on to do its job, but be able to intercept method calls and return values. In order to test private methods, you will need to refactor the code to change the access to protected (or package) and you will have to avoid static/final methods. By continuing to use Pastebin, you agree to our use of cookies as described in the Cookies Policy. Mockito Tutorial : Learn mocking with 25 Junit Examples and Mockito to mock a constructor. JUnit & Mockito, First steps @QuadraticBEJul. This is perfect for exposing a complex object that never changes over time without writing a StatefulWidget. After an unstub you can’t verify() anymore because all interactions will be forgotten. Another common pattern is to use test data builders to create the values that you need. EDIT: As of Spring Boot 1. Learn Unit Testing with Junit & Mockito in 30 Steps Udemy Download Free Tutorial Video - Learn Mockito and JUnit - the most popular unit testing and mocking frameworks - with 25 Example. ICM MOSKVICH copy scale constructor 1 35, Airfix 1 48 Dassault Super Etendard Plastic Aircraft Model Kit, Hillman Imp Mk2 CORVA02624 New , Paddle Steamer Goethe 1 160 Revell Model Gift Set, Remote Control Dynam T28 Trojan W Retracts 1270Mm W O Tx Rx Batt. Mockito provides mechanisms for mocking most of the stuff you need, but remains mysteriously silent on constructor mocking. When Mockito creates a mock – it does so from the Class of a Type, not from an actual instance. Properties are injected even if private is applied. See also javadoc Mockito. JUnit & Mockito, first steps 1. Mockito の verify() では equals() による同値性の検証が行われます。通常この方法は簡素であり推奨されますが、引数のキャプチャにて以下のようなアサーションを行うことができます。. mockito:mockito-core. spy() and mock() are two different things. Mockito verifies argument values in natural java style: by using an equals() method. But Mockito cannot instantiate inner classes, local classes, abstract classes and interfaces. So if we were curious about knowing more precisely about that object, what we would have to do is to spy on it. doNothing (). Read Spring Boot docs for more info. Requirement: Again, taking a fictitious example, lets say that ServiceA creates an instance of ServiceB and invokes a businessOperation on ServiceB's. TestNG & Mockito example showing how to use TestNG & Mockito together, when to use Mockito, mock with @Mock, @Spy, @InjectMocks, @Captor, stub void methods. The constructor of the URI is intercepted and we return a “realUri”, i. When you work with legacy codebase, sometime you would like to avoid the call to super constructor and super methods so that you can focus on covering sub class. Let's say we have a class defined as:. Constructors Should Not Do Any Work. getValue() to the assert the captured argument value. If you already read some other blog post about unusual mocking, you can skip prelude via this link. Mockito provides a method called argThat() in org. Note: Keep in mind the current version is as and when I am learning mockito myself. Constructor Based Injection – Utilizes Constructor for the class under test. Cylinder Hand Held Vacuum Pump Handle Brass Brake Bleeder Kit Cars Motorcycles,MAURITIUS 15 DOLLARS P S123 1839 BUILDING SHIP RARE BANK NOTE CURRENCY MONEY,The Iron Dome Medal 2012 - 50mm Bronze Medals Collectible Gift Commemorative. JUnit testing – part II – using Mockito for dependencies configuration So, in case you haven’t read the first part in this series, which is giving some basic introduction to the idea of junit testing – go ahead, I’ll wait till you’re back so that we can proceed with the next steps. Mockito as shown in line no. In the above example the field ArticleManager annotated with @InjectMocks could have a parameterized constructor only, a no-arg constructor only, or both. spy() is a recommended way of creating partial mocks. The reason is it guarantees real methods are called against correctly constructed object because you're responsible for constructing the object passed to spy() method. Mockito 中文文档 ( 2. The provider will call that function only once, when inserting the widget in the tree, and expose the result. IntelliJ + Android + Unit Testing + PowerMockito + EasyMock + Mockito + Roboelectric Posted by ihusyn on July 30, 2017 in Android , Development , Mobile Application Development References:. This tutorial shows you how to use the spring c-namespace. Instantiate the class by calling the default constructor. Mockito provides a method called argThat() in org. Refine search. MockitoAnnotations. You can find it here. This is really quite convenient. Taking advantage of advanced mocks configuration. When spy is called, then actual method of real object is called.