Is it right to use Mockito.reset() in #Before method for mock objects which is being used in more than test method in the same test Class as shown below.
public class SampleTest {
#Mock
private CustomRepository customRepo;
#Before
public void setUp() {
Mockito.reset(customRepo);
}
#Test
public void test1(){
......
given(customRepo.someMethod()).willReturn(Answer1);
......
}
#Test
public void test2(){
......
given(customRepo.someMethod()).willReturn(Answer2);
......
}
}
You don't have to reset the mock because JUnit/Mockito creates a new instance of SampleTest and the mock object for each test.
Related
I have a class Room, where I inject Optional Person object, this is coming null while running testSuccess. My understanding is it should come non null, since I am setting this to new Person() at the start of the test. Why is it coming null?
public class Room{
#Inject
private Optional<Person> person1
//this is coming null when running test
}
My unit test
public class RoomTest {
#Inject Mocks
private Room testRoom
.....
//Other mocks
private Optional<Person> testPerson
//Not able to mock this since its optional, hence directly setting value in unit test.
#Before
public void setUp() throws Exception {
MockitoAnnotations.initMocks(this);
}
#Test
public void testSuccess() {
testPerson = Optional.of(new Person());
....
}
}
As the name implies, #InjectMocks only injects #Mocks. The testPerson is not a mock. Why not just add an #Inject-ing constructor to the Room class that would accept a person? This way you could just instantiate a testRoom in your test method and your dependency injection will still work.
public class Room{
private Optional<Person> person;
#Inject
public Room(Optional<Person> person) {
this.person = person;
}
}
public class RoomTest {
#Test
public void testSuccess() {
Optional<Person> testPerson = Optional.of(new Person());
Room room = new Room(testPerson);
...
}
}
That said, if you absolutely want to use the annotations and adding the constructor is not an option for you then you can use PowerMock runner to mock the Optional. Conceptually, it can look like the code below. But usually, if you have to use PowerMock there might be something wrong with the code :)
public class Room{
#Inject
private Optional<Person> person;
}
// This is for JUnit4. Using Powermock with JUnit5 will be more involved
#RunWith(PowerMockitoRunner.class)
#PrepareForTest(Optional.class) // to mock the final class
public class RoomTest {
#InjectMocks
private Room testRoom;
#Mock
private Optional<Person> testPerson;
#Before
public void setUp() throws Exception {
MockitoAnnotations.initMocks(this);
}
#Test
public void testSuccess() {
...
}
}
I am trying to mock a simple shared preferences using Mockito . Since, the examples on google are too complicated to make anything out of it, I decided to go ahead on my own.
The shared preferences are setup using dagger.
It crashes with NPE in the saveString method in the SharedPreferenceManager class on the putString line.
#Module
public class StudentModule {
#Provides
#Singleton
static Context getContext(Application application) {
return application.getApplicationContext();
}
#Provides
#Singleton
static SharedPreferences getSharedPreferences(Context context) {
return PreferenceManager.getDefaultSharedPreferences(context);
}
}
There is a manager class:
public class SharedPreferenceManager {
private SharedPreferences sharedPreferences;
private Context context;
#Inject public SharedPreferenceManager(SharedPreferences sharedPreferences, Context context){
this.sharedPreferences=sharedPreferences;
this.context=context;
}
public String doSomething(){
return sharedPreferences.getString("s","");
}
public void saveString(String s){
System.out.println(sharedPreferences.getClass().getSimpleName());
SharedPreferences.Editor editor=sharedPreferences.edit();
editor.putString("s","bis").apply();
}
}
Here is the test:
#RunWith(MockitoJUnitRunner.class)
public class MockTest {
#InjectMocks
SharedPreferenceManager sharedPreferenceManager;
#Mock SharedPreferences sharedPreferences;
#Before
public void setup() {
MockitoAnnotations.initMocks(this);
}
#Test
public void isSharedPefWorking(){
sharedPreferenceManager.saveString("bis");
assertEquals("bis",sharedPreferenceManager.doSomething());
}
}
SharedPreferences uses a SharedPreferences.Editor which you're not currently mocking.
You would need to do something like the following to mock and verify the behaviour of your SharedPreferenceManager.
#RunWith(MockitoJUnitRunner.class)
public class MockTest {
#InjectMocks
SharedPreferenceManager sharedPreferenceManager;
#Mock
SharedPreferences sharedPreferences;
#Mock
SharedPreferences.Editor sharedPreferencesEditor;
final String savedString = "savedString";
#Before
public void setup() {
MockitoAnnotations.initMocks(this);
when(sharedPreferences.edit()).thenReturn(sharedPreferencesEditor);
when(sharedPreferencesEditor.putString(anyString(), anyString())).thenReturn(sharedPreferencesEditor);
}
#Test
public void saveString() {
sharedPreferenceManager.saveString(savedString);
verify(sharedPreferencesEditor).putString("s", savedString);
}
#Test
public void getString() {
when(sharedPreferences.getString("s","")).thenReturn(savedString);
String preferenceString = sharedPreferenceManager.doSomething();
assertEquals(preferenceString, savedString);
}
}
I'm trying to unit test code that runs as callback in a Consumer functional interface.
#Component
class SomeClass {
#Autowired
private SomeInteface toBeMockedDependency;
public method() {
toBeMockedDependency.doSomething(message -> {
// Logic under test goes here
// (implements java.util.function.Consumer interface)
...
});
}
}
#RunWith(MockitoJUnitRunner.class)
public class SomeClassTest {
#InjectMocks
private SomeClass someClass;
#Mock
private SomeInteface toBeMockedDependency;
#Test
public void testMethod() {
...
someClass.method();
...
}
}
Essentially I want to provide the tested code some tested "message" via "toBeMockedDependency".
How can the "toBeMockedDependency" be mocked to provide a predefined message?
Is it the right approach?
Don't try to make toBeMockedDependency automatically call your functional interface. Instead, use a #Captor to capture the anonymous functional interface, and then use your test to manually call it.
#RunWith(MockitoJUnitRunner.class)
public class SomeClassTest {
#InjectMocks
private SomeClass someClass;
#Mock
private SomeInteface toBeMockedDependency;
#Captor
private ArgumentCaptor<Consumer<Message>> messageConsumerCaptor;
#Test
public void testMethod() {
someClass.method();
verify(toBeMockedDependency).doSomething(messageConsumerCaptor.capture());
Consumer<Message> messageConsumer = messageConsumerCaptor.getValue();
// Now you have your message consumer, so you can test it all you want.
messageConsumer.accept(new Message(...));
assertEquals(...);
}
}
I am using Mockito to write a simple unit test. I have a smiple abstract class which implements Runnable:
public abstract class MyRunnable implements Runnable {
#Override
public void run() {
doTask();
}
public abstract void doTask();
}
Then, a function under test uses MyRunnable:
public class MyService {
public void something() {
executor.execute(new MyRunnable() {
#Override
doTask() {
…
}
});
}
}
My test case, I want to test doTask() has run :
#Test
public void testSomething() {
…
ArgumentCaptor<MyRunnable> myCaptor = ArgumentCaptor.forClass(MyRunnable.class);
verify(mockMyService).something(myCaptor.capture());
// get what has been captured
MyRunnable myRunnable = myCaptor.getValue();
//verify doTask() has run , but got ERROR.
verify(myRunnable).doTask();
}
My test case throw the following error:
org.mockito.exceptions.misusing.NotAMockException:
Argument passed to verify() is of type and is not a mock!
The error complains that verify() only accept mocked object. Then, how can I verify/test that the captured MyRunnable object has run doTask() with Mockito?
If you have control over your codebase, you can make your code testable with Mockito by moving any code that uses the new keyword into a separate Factory class like so...
public class MyService {
private MyRunnableFactory = factory;
public MyService(MyRunnableFactory factory) {
this.factory = factory;
}
public void something() {
executor.execute(factory.createInstance());
}
}
Then your test can simply inject a Mock of the factory which you can verify its behaviour/interactions
#Mock MyRunnableFactory factory;
#Mock MyRunnable myRunnable;
#Test
public void testSomething() {
when(factory.createInstance()).thenReturn(myRunnable);
// method under test
MyService service = new MyService();
service.something();
verify(myRunnable).doTask();
}
I use a rule of thumb that classes that creates objects, shouldn't have any business logic, so you don't have these testing headaches. This is essentially the Single Responsibilty Principal
You can't do this with Mockito because MyRunnable is created by the code under test. But you may have a look at PowerMock because it allows you to mock the constructor: https://github.com/jayway/powermock/wiki/MockConstructor
So i have a class that needs to be tested. Lets call it ClassToTest. It has a couple of Dao objects as fields.
Public class ClassToTest {
#Autowired
MyDao dao;
void methodToTest() {
dao.save(something);
}
}
As you can see ClassToTest does not contain any constructor or setter and I am using spring to autowire the fields.
Now, I have a base test class with all the dependencies that classToTest requires:
public abstract BaseTest {
#Mock
MyDao dao;
}
And the testClass extends this BaseTest class :
public class TestClass extends BaseTest {
#InjectMocks
ClassToTest classToTest = new ClassToTest();
#Before
public void setup() {
MockitoAnnotations.initMocks(this);
}
#Test
public void test() {
classToTest.methodToTest();
}
}
This results in a null pointer exception when the save happens. However, if i change setup method to this :
#Before
public void setup() {
MockitoAnnotations.initMocks(this);
classToTest.dao = dao;
}
the test passes.
My understanding was that when a class does not have a constructor or a setter, InjectMocks would inject the mocks by using field injection. Why is that not happening here?
Figured out that this is a bug in the 1.8.5 version that i was using : https://code.google.com/p/mockito/issues/detail?id=229.
Upgrading 1.10 fixed the issue.