I have a final class, something like this:
public final class RainOnTrees{
public void startRain(){
// some code here
}
}
I am using this class in some other class like this:
public class Seasons{
RainOnTrees rain = new RainOnTrees();
public void findSeasonAndRain(){
rain.startRain();
}
}
and in my JUnit test class for Seasons.java I want to mock the RainOnTrees class. How can I do this with Mockito?
Mocking final/static classes/methods is possible with Mockito v2 only.
add this in your gradle file:
testImplementation 'org.mockito:mockito-inline:2.13.0'
This is not possible with Mockito v1, from the Mockito FAQ:
What are the limitations of Mockito
Needs java 1.5+
Cannot mock final classes
...
Mockito 2 now supports final classes and methods!
But for now that's an "incubating" feature. It requires some steps to activate it which are described in What's New in Mockito 2:
Mocking of final classes and methods is an incubating, opt-in feature. It uses a combination of Java agent instrumentation and subclassing in order to enable mockability of these types. As this works differently to our current mechanism and this one has different limitations and as we want to gather experience and user feedback, this feature had to be explicitly activated to be available ; it can be done via the mockito extension mechanism by creating the file src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker containing a single line:
mock-maker-inline
After you created this file, Mockito will automatically use this new engine and one can do :
final class FinalClass {
final String finalMethod() { return "something"; }
}
FinalClass concrete = new FinalClass();
FinalClass mock = mock(FinalClass.class);
given(mock.finalMethod()).willReturn("not anymore");
assertThat(mock.finalMethod()).isNotEqualTo(concrete.finalMethod());
In subsequent milestones, the team will bring a programmatic way of using this feature. We will identify and provide support for all unmockable scenarios. Stay tuned and please let us know what you think of this feature!
add this in your build file:
if using gradle: build.gradle
testImplementation 'org.mockito:mockito-inline:2.13.0'
if using maven: pom.xml
<dependency>
<groupId>org.mockito</groupId>
<artifactId>mockito-inline</artifactId>
<version>2.13.0</version>
<scope>test</scope>
</dependency>
this is a configuration to make mockito work with final classes
If you faced the Could not initialize inline Byte Buddy mock maker. (This mock maker is not supported on Android.)
Add the Byte Buddy dependency to your build.gradle file:
testImplementation 'net.bytebuddy:byte-buddy-agent:1.10.19'
src: https://mvnrepository.com/artifact/net.bytebuddy/byte-buddy
You cannot mock a final class with Mockito, as you can't do it by yourself.
What I do, is to create a non-final class to wrap the final class and use as delegate. An example of this is TwitterFactory class, and this is my mockable class:
public class TwitterFactory {
private final twitter4j.TwitterFactory factory;
public TwitterFactory() {
factory = new twitter4j.TwitterFactory();
}
public Twitter getInstance(User user) {
return factory.getInstance(accessToken(user));
}
private AccessToken accessToken(User user) {
return new AccessToken(user.getAccessToken(), user.getAccessTokenSecret());
}
public Twitter getInstance() {
return factory.getInstance();
}
}
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).
In your case I would create a non-final RainOnTrees class that delegate to the final class. Or, if you can make it non-final, it would be better.
In Mockito 3 and more I have the same problem and fixed it as from this link
Mock Final Classes and Methods with Mockito
as follow
Before Mockito can be used for mocking final classes and methods, it needs to be > configured.
We need to add a text file to the project's src/test/resources/mockito-extensions directory named org.mockito.plugins.MockMaker and add a single line of text:
mock-maker-inline
Mockito checks the extensions directory for configuration files when it is loaded. This file enables the mocking of final methods and classes.
Use Powermock. This link shows, how to do it: https://github.com/jayway/powermock/wiki/MockFinal
Just to follow up. Please add this line to your gradle file:
testCompile group: 'org.mockito', name: 'mockito-inline', version: '2.8.9'
I have tried various version of mockito-core and mockito-all. Neither of them work.
I had the same problem. Since the class I was trying to mock was a simple class, I simply created an instance of it and returned that.
I guess you made it final because you want to prevent other classes from extending RainOnTrees. As Effective Java suggests (item 15), there's another way to keep a class close for extension without making it final:
Remove the final keyword;
Make its constructor private. No class will be able to extend it because it won't be able to call the super constructor;
Create a static factory method to instantiate your class.
// No more final keyword here.
public class RainOnTrees {
public static RainOnTrees newInstance() {
return new RainOnTrees();
}
private RainOnTrees() {
// Private constructor.
}
public void startRain() {
// some code here
}
}
By using this strategy, you'll be able to use Mockito and keep your class closed for extension with little boilerplate code.
Another workaround, which may apply in some cases, is to create an interface that is implemented by that final class, change the code to use the interface instead of the concrete class and then mock the interface. This lets you separate the contract (interface) from the implementation (final class). Of course, if what you want is really to bind to the final class, this will not apply.
Time saver for people who are facing the same issue (Mockito + Final Class) on Android + Kotlin. As in Kotlin classes are final by default. I found a solution in one of Google Android samples with Architecture component. Solution picked from here : https://github.com/googlesamples/android-architecture-components/blob/master/GithubBrowserSample
Create following annotations :
/**
* This annotation allows us to open some classes for mocking purposes while they are final in
* release builds.
*/
#Target(AnnotationTarget.ANNOTATION_CLASS)
annotation class OpenClass
/**
* Annotate a class with [OpenForTesting] if you want it to be extendable in debug builds.
*/
#OpenClass
#Target(AnnotationTarget.CLASS)
annotation class OpenForTesting
Modify your gradle file. Take example from here : https://github.com/googlesamples/android-architecture-components/blob/master/GithubBrowserSample/app/build.gradle
apply plugin: 'kotlin-allopen'
allOpen {
// allows mocking for classes w/o directly opening them for release builds
annotation 'com.android.example.github.testing.OpenClass'
}
Now you can annotate any class to make it open for testing :
#OpenForTesting
class RepoRepository
Actually there is one way, which I use for spying. It would work for you only if two preconditions are satisfied:
You use some kind of DI to inject an instance of final class
Final class implements an interface
Please recall Item 16 from Effective Java. You may create a wrapper (not final) and forward all call to the instance of final class:
public final class RainOnTrees implement IRainOnTrees {
#Override public void startRain() { // some code here }
}
public class RainOnTreesWrapper implement IRainOnTrees {
private IRainOnTrees delegate;
public RainOnTreesWrapper(IRainOnTrees delegate) {this.delegate = delegate;}
#Override public void startRain() { delegate.startRain(); }
}
Now not only can you mock your final class but also spy on it:
public class Seasons{
RainOnTrees rain;
public Seasons(IRainOnTrees rain) { this.rain = rain; };
public void findSeasonAndRain(){
rain.startRain();
}
}
IRainOnTrees rain = spy(new RainOnTreesWrapper(new RainOnTrees()) // or mock(IRainOnTrees.class)
doNothing().when(rain).startRain();
new Seasons(rain).findSeasonAndRain();
Give this a try:
Mockito.mock(SomeMockableType.class,AdditionalAnswers.delegatesTo(someInstanceThatIsNotMockableOrSpyable));
It worked for me. "SomeMockableType.class" is the parent class of what you want to mock or spy, and someInstanceThatIsNotMockableOrSpyable is the actual class that you want to mock or spy.
For more details have a look here
This can be done if you are using Mockito2, with the new incubating feature which supports mocking of final classes & methods.
Key points to note:
1. Create a simple file with the name “org.mockito.plugins.MockMaker” and place it in a folder named “mockito-extensions”. This folder should be made available on the classpath.
2. The content of the file created above should be a single line as given below:
mock-maker-inline
The above two steps are required in order to activate the mockito extension mechanism and use this opt-in feature.
Sample classes are as follows:-
FinalClass.java
public final class FinalClass {
public final String hello(){
System.out.println("Final class says Hello!!!");
return "0";
}
}
Foo.java
public class Foo {
public String executeFinal(FinalClass finalClass){
return finalClass.hello();
}
}
FooTest.java
public class FooTest {
#Test
public void testFinalClass(){
// Instantiate the class under test.
Foo foo = new Foo();
// Instantiate the external dependency
FinalClass realFinalClass = new FinalClass();
// Create mock object for the final class.
FinalClass mockedFinalClass = mock(FinalClass.class);
// Provide stub for mocked object.
when(mockedFinalClass.hello()).thenReturn("1");
// assert
assertEquals("0", foo.executeFinal(realFinalClass));
assertEquals("1", foo.executeFinal(mockedFinalClass));
}
}
Hope it helps.
Complete article present here mocking-the-unmockable.
Yes same problem here, we cannot mock a final class with Mockito. To be accurate, Mockito cannot mock/spy following:
final classes
anonymous classes
primitive types
But using a wrapper class seems to me a big price to pay, so get PowerMockito instead.
I think you need think more in principle. Instead you final class use his interface and mock interface instead.
For this:
public class RainOnTrees{
fun startRain():Observable<Boolean>{
// some code here
}
}
add
interface iRainOnTrees{
public void startRain():Observable<Boolean>
}
and mock you interface:
#Before
fun setUp() {
rainService= Mockito.mock(iRainOnTrees::class.java)
`when`(rainService.startRain()).thenReturn(
just(true).delay(3, TimeUnit.SECONDS)
)
}
Please look at JMockit. It has extensive documentation with a lot of examples. Here you have an example solution of your problem (to simplify I've added constructor to Seasons to inject mocked RainOnTrees instance):
package jmockitexample;
import mockit.Mocked;
import mockit.Verifications;
import mockit.integration.junit4.JMockit;
import org.junit.Test;
import org.junit.runner.RunWith;
#RunWith(JMockit.class)
public class SeasonsTest {
#Test
public void shouldStartRain(#Mocked final RainOnTrees rain) {
Seasons seasons = new Seasons(rain);
seasons.findSeasonAndRain();
new Verifications() {{
rain.startRain();
}};
}
public final class RainOnTrees {
public void startRain() {
// some code here
}
}
public class Seasons {
private final RainOnTrees rain;
public Seasons(RainOnTrees rain) {
this.rain = rain;
}
public void findSeasonAndRain() {
rain.startRain();
}
}
}
Solutions provided by RC and Luigi R. Viggiano together is possibly the best idea.
Although Mockito cannot, by design, mock final classes, the delegation approach is possible. This has its advantages:
You are not forced to change your class to non-final if that is what your API intends in the first place (final classes have their benefits).
You are testing the possibility of a decoration around your API.
In your test case, you deliberately forward the calls to the system under test. Hence, by design, your decoration does not do anything.
Hence you test can also demonstrate that the user can only decorate the API instead of extending it.
On a more subjective note:
I prefer keeping the frameworks to a minimum, which is why JUnit and Mockito are usually sufficient for me. In fact, restricting this way sometimes forces me to refactor for good as well.
If you trying to run unit-test under the test folder, the top solution is fine. Just follow it adding an extension.
But if you want to run it with android related class like context or activity which is under androidtest folder, the answer is for you.
Add these dependencies for run mockito successfully :
testImplementation 'org.mockito:mockito-core:2.24.5'
testImplementation "org.mockito:mockito-inline:2.24.5"
Mocking final classes is not supported for mockito-android as per this GitHub issue. You should use Mockk instead for this.
For both unit test and ui test, you can use Mockk with no problem.
If you need to use Mockito in an instrumented test in Android (i. e. running in an Android device), you cannot use mockito-inline. There is a special mockito-android version which doesn't solve the "final class" problem either. The only solution which seems to work is the Dexmaker library. The only limitation is that it works only in Android P (Android 9, API 28) and higher. It can be imported as follows:
androidTestImplementation "com.linkedin.dexmaker:dexmaker-mockito-inline:2.28.1"
Beware that there is also a "dexmaker-mockito" version which doesn't work for final classes either. Make sure you import "dexmaker-mockito-inline".
As others have stated, this won't work out of the box with Mockito. I would suggest using reflection to set the specific fields on the object that is being used by the code under test. If you find yourself doing this a lot, you can wrap this functionality in a library.
As an aside, if you are the one marking classes final, stop doing that. I ran across this question because I am working with an API where everything was marked final to prevent my legitimate need for extension (mocking), and I wish that the developer had not assumed that I would never need to extend the class.
For us, it was because we excluded mockito-inline from koin-test. One gradle module actually needed this and for reason only failed on release builds (debug builds in the IDE worked) :-P
For final class add below to mock and call static or non static.
1- add this in class level
#SuppressStatucInitializationFor(value ={class name with package})
2- PowerMockito.mockStatic(classname.class) will mock class
3- then use your when statement to return mock object when calling method of this class.
Enjoy
I was able to overcome this message:
org.mockito.exceptions.base.MockitoException:
Cannot mock/spy class org.slf4j.impl.Log4jLoggerAdapter
Mockito cannot mock/spy because :
final or anonymous class
from this: log = spy(log);
By using this instead:
log = mock(Logger.class);
Then it works.
I guess that "default" logger adapter is an instance of a final class so I couldn't "spy" it, but I could mock the whole thing. Go figure...
This may mean that you could substitute it for some other "non final" instance if you have that handy, as well. Or a simplified version, etc. FWIW...
I am writing the steps I followed after various unsuccessful attempts to mock final/private classes and their methods in Java 11, which finally worked for me.
Create a file named org.mockito.plugins.MockMaker inside
your test/resources/mockito-extensions folder. Please create
mockito-extensions folder if not present already.
Add a single line mock-maker-inline as the content of the above org.mockito.plugins.MockMaker file
Add
#RunWith(PowerMockRunner.class)
#PowerMockIgnore({"javax.management.*", "jdk.internal.reflect.*", "com.sun.org.apache.xerces.*", "javax.xml.*", "org.xml.*", "org.w3c.*"})
#PrepareForTest(Utility.class)
annotations at the class level.
Setup process in the test class
#Before
public void setup () {
MockitoAnnotations.initMocks(this);
Mockito.mockStatic(ClassToBeMocked.class);
}
Use Mockito.when(..).thenReturn(..) for assertions
In case of multiple test cases, add the below code
#After
public void after() {
Mockito.framework().clearInlineMocks();
}
The mockito version which I am using: 3.9.0
Java version: 11
Didn't try final, but for private, using reflection remove the modifier worked ! have checked further, it doesn't work for final.
I am using reason code entries in a Dialog form.
For writing the unit Test for the above, I need to first insert reasonCodes dynamically via code in setUpTestCase in UnitTestFramework in Dynamics AX 2012.
How can I do this? I havnt found any help on the internet yet.
Self learned the answer.
In order to write a Unit Test using UnitTestFramework, you create a class which extends SysTestCase class (a System class).
setUp(), setUpTestCase(), tearDown(), tearDownTestCase() are base class functions which are used for setting up and destroying the data during purposely for the test case.
setUp() & tearDown() methods are called at the start & end respectively for each test function in the test case class.
Note, setUp(), tearDown() is run once for every test function while setUpTestCase(), tearDownTestCase() is run only once for for a unit test at the start and end respectively.
Coming back to what I asked,
I had to setup reason codes together with reason comments for writing the test case.
Following is the X++ code required to do so.
private void createReason(str _reasonCode, str _reasonComment)
{
ReasonTable _reasonTable;
_reasonTable.clear();
_reasonTable.Asset = NoYes::Yes;
_reasonTable.Ledger = NoYes::Yes;
_reasonTable.Reason = _reasonCode;
_reasonTable.Description = _reasonComment;
_reasonTable.doInsert();
}
You might have different setting to setup reasons in your test case.
Example, you might wamt to set
_reasonTable.Asset = NoYes::No;
instead of
_reasonTable.Asset = NoYes::Yes;
Call createReason() function in the setUpTestCase() and reasons are inserted into database.
That's all. Hope that it helps someone at some point of time.
Be happy.
~Shakir Shabbir
Have you tried the setUp() and tearDown() methods on the test class?
http://msdn.microsoft.com/EN-US/library/bb496539.aspx
You can create data before the test class execution and delete it when testing ends.
I'm trying to override the +initialize method of a class using ASOC, but I cannot find a way to override a class method. Is it even possible?
Not to let any confusion possible about the language I'm talking about, here's some code:
script FLAppDelegate
property parent: class "NSObject"
-- -- Class Methods -- --
-- Insert code here
end script
I've done some tests, and as far as I can tell, weird as it is, methods defined using AppleScriptObjC are both class and instance methods.
Let's say I have an AppleScriptObjC file:
script iTunesController
property parent: class "NSObject"
on playpause()
tell application id "com.apple.iTunes" to playpause
end playpause
end script
In an Objective-C method, both:
- (void)callASOC
{
iTunesControllerInstance = [NSClassFromString(#"iTunesController") new];
[iTunesControllerInstance playpause];
[iTunesControllerInstance release];
}
and
- (void)callASOC
{
[NSClassFromString(#"iTunesController") playpause];
}
will call the playpause handler in the AppleScriptObjC file. The latter formulation will generate a warning a compile time, but works.
I was not able to find any documentation confirming or refuting this.
Thanks to #Friziab who reminded me of the NSClassFromString
So I could call a AppleScriptObjC method in my AppDelegate.applescript from another class (script) (NSView subclass)
I don't use AppleScriptObjC so there may be a proper way of doing it but this worked
current application's NSClassFromString("AppDelegate")'s popWindow()
I'm trying to create a unit test for a code similar to this:
foreach (string domainName in Directory.GetDirectories(server.Path))
{
HandleDomainDirectory(session, server, domainName);
}
The problem is that I'm using the System.IO.Directory class in my code.
How can I create a testing method that won't be dependent on any folder I have on my hard disk.
In other words, How can I fake the response of "Directory.GetDirectories(server.Path)"?
(Please note, I do control the "server" object in my class, therefore i can give any path i want)
Thanks.
Rather than calling Directory.GetDirectories(server.Path) directly, you could create an interface like IDirectoryResolver with a single method that takes a path string and returns the list of directories. The class containing your code above would then need a property or field of type IDirectoryResolver, which can be injected through the constructor or a setter.
For your production code, you would then create a new class that implements the IDirectoryResolver interface. This class could use the Directory.GetDirectories method in its implementation of the interface method.
For unit testing, you could create a MockDirectoryResolver class which implements IDirectoryResolver (or use a mocking library to create a mock instance for the interface). The mock implementation can do whatever you need it to do.
You would inject a wrapper class.
public class DirectoryFetcher
{
public virtual List<string> GetDirectoriesIn(string directory)
{
return Directory.GetDirectories(directory);
}
}
And then inject that:
foreach(string directory in _directoryFetcher.GetDirectoriesIn(server.Path))
{
// Whatever
}
You can then Mock that guy at the injection point (this example uses Moq, and constructor injection):
Mock<DirectoryFetcher> mockFetcher = new Mock<DirectoryFetcher>();
mockFetcher.Setup(x => x.GetDirectoriesIn("SomeDirectory")).Returns(new List<string>
{
"SampleDirectory1",
"SampleDirectory2"
});
MyObjectToTest testObj = new MyObjectToTest(mockFetcher.Object);
// Do Test
When communicating with the outside world, such as file system, databases, web services etc. , you should always consider using wrapper classes like the others before me suggested. Testability is one major argument, but an even bigger one is: The out side world changes, and you have no control over it. Folders move, user rights changes, new disk drives appears and old ones are removed. You only want to care about stuff like that in one place. Hence, the wrapper -- let's call it DirectoryResolver like Andy White suggested ealier.
So, wrap your file system calls, extract an interface, and inject that interface where you need to communicate with the file system.
The best solution I've found was to use Moles. The code is very specific, and must do very specific thing. Wrapping it with wrapper class will be redundant. The only reason I needed wrapper class is in order to write tests. Moles allows me to write the tests without any wrapper class :)
This seems like an easy enough issue but I can't seem to find the keywords to effect my searches.
I'm trying to unit test by mocking out all objects within this method call. I am able to do so to all of my own creations except for this one:
public void MyFunc(MyVarClass myVar)
{
Image picture;
...
picture = Image.FromStream(new MemoryStream(myVar.ImageStream));
...
}
FromStream is a static call from the Image class (part of c#). So how can I refactor my code to mock this out because I really don't want to provide a image stream to the unit test.
You can create an IImageLoader interface. The "normal" implementation just calls Image.FromStream, while your unit test version can do whatever you need it to do.
Moq and most other mocking frameworks don't support mocking out static methods. However, TypeMock does support mocking out static methods and that might be of interest to you if you're willing to purchase it. Otherwise, you'll have to refactor so that an interface can be mocked...
You could wrap the static function into Func type property which can be set by the unit test with a mock or stub.
public class MyClass
{
..
public Func<Image, MemoryStream> ImageFromStream =
(stream) => Image.FromStream(stream);
public void MyFunc(MyVarClass myVar)
{
...
picture = ImageFromStream(new MemoryStream(myVar.ImageStream));
...
}
..
}
This can be acheived with Moles, a Visual Studio 2010 Power Tools. The Moles code would look like this:
// replace Image.FromStream(MemoryStream) with a delegate
MImage.FromStreamMemoryStream = stream => null;