Value of doReturn not used - spring-boot

I use spring boot 2.
I search to test a private method in the facade
#RunWith(SpringRunner.class)
#SpringBootTest
public class SamplingsFacadeTest {
#Autowired
private SamplingsFacade facade;
#MockBean
private SamplingsService samplingsService;
#Test
public void exampleTest() throws Exception {
List<Samplings> samplings = new ArrayList<>();
Samplling sampling = new Samplings();
..
samplings.add(sampling);
//fake call
Mockito.doReturn(samplings).when(samplingsService.getSamplingContainingNonCompliantTest());
//real call
List<FactoryEmailNCDto> factoryEmails = Whitebox.invokeMethod(facade, "prepareDataNoncompliantSampling");
}
public List<Samplings> getSamplingContainingNonCompliantTest() {
return samplingsRepository.findSamplingContainingNonCompliantTest();
}
In Facade In
private List<FactoryEmailNCDto> prepareDataNoncompliantSampling() {
List<FactoryEmailNCDto> factoryEmailNC = new ArrayList<>();
List<Samplings> samplings = samplingsService.getSamplingContainingNonCompliantTest();
for (Samplings sampling : samplings) {
...
}
}
Why when I debug, samplings is null and not the value I created

Mockito.doReturn(samplings)
.when(samplingsService.getSamplingContainingNonCompliantTest());
One potential problem is that doReturn takes the form doReturn(value).when(mock).method(), not doReturn(value).when(mock.method()). The latter is considered an incomplete stubbing. Instead, it should look like this:
Mockito.doReturn(samplings)
.when(samplingsService)
.getSamplingContainingNonCompliantTest();
Note that there may be other problems with your test; the code you've written expects samplingsService to be public and non-final, and your getSamplingContainingNonCompliantTest() to likewise be public, non-static, and non-final, but the code sample you have does not confirm that. You may want to call Mockito.validateMockitoUsage() in an #After method, or use a #Rule that handles Mockito annotations and cleanup for you.

Related

Dependency injection with mockito example

I am very new with Mockito and I don't get the following example (classes were provided, only test to write) and how to solve it.
What I try to do is use a test double for the supplier so that we can control the returned greeting in the test and assert that the GreetingService does not modify the greeting message in any way. Then assert that the returned greeting string is equal to "Hello Andy.".
public class Greeting {
private final String template;
public Greeting(String template) {
this.template = template;
}
public String forName(String world) {
return String.format(template, world);
}
}
#Component
public class GreetingService {
private final Supplier<Greeting> greetingSupplier;
public GreetingService(Supplier<Greeting> greetingSupplier) {
this.greetingSupplier = greetingSupplier;
}
public String greet(String name) {
return greetingSupplier.get().forName(name);
}
}
#Component
public class RandomGreetingSupplier implements Supplier<Greeting> {
private final List<Greeting> greetings = Arrays.asList(
new Greeting("Hello %s."),
new Greeting("Hi %s!"),
);
private final Random random = new Random();
#Override
public Greeting get() {
return greetings.get(random.nextInt(greetings.size()));
}
}
#SpringBootTest
public class GreetingServiceTest {
#Autowired
GreetingService greetingService;
#MockBean
Supplier<Greeting> greetingSupplier;
#Test
void getGreetingForPerson() {
String name = "Andy";
// that test cannot know which greeting will be returned by the supplier
// WHY IS IT NULLPOINTEREXCEPTION AFTER INITIALIZING #MockBean
//String greeting = greetingService.greet(name);
//assertThat(greeting).contains(name);
// WROTE SUCH TEST HERE -> NullPointerException WHY?
Mockito.when(greetingSupplier.get().forName(name)).thenReturn("Hello %s.");
assertThat(greetingSupplier.equals("Hello Andy."));
// THIS IS WORKING & TEST PASSED BUT I GUESS ITS WRONG?
Mockito.when(greetingSupplier.get()).thenReturn(new Greeting("Hello %s."));
assertThat(greetingSupplier.equals("Hello Andy."));
}
}
Mockito.when(greetingSupplier.get().forName(name)).thenReturn("Hello %s.");
You can't chain calls like that, you need to produce intermediate results, like
Supplier<Greeting> supplier = mock(Supplier.class);
Mockito.when(supplier).forName().thenReturn("Hello %s.");
Mockito.when(greetingSupplier.get()).thenReturn(supplier);
For dependency injection, you need to create the subject under test with the mocked Supplier. You can do that in a #Before method for example.
Your mocking is wrong.
Mockito.when(greetingSupplier.get().forName(name)).thenReturn("Hello %s.");
You mocked Supplier<Greeting> and the default behavior is to return null. So when you call greetingSupplier.get() in your first line it returns null. You directly chain forName which nou basicall is null.forName which leads to an error.
Your second part is actually (kind of) correct.
Mockito.when(greetingSupplier.get()).thenReturn(new Greeting("Hello %s."));
You now properly return a response from greetingSupplier.get(). Instead of chaining the call.
However I would argue that your excercise is wrong. Why? When using a Supplier<?> in Spring it actually is a lazy beanFactory.getBean call. You can lazily inject dependencies this way. You should have a mock for Greeting which returns a hardcoded String which you can check.

Spring boot with Mockito mocking NamedParameterJdbcTemplate

Trying to unit test a method which is defined as :
public void myMethod(List<? extends MyModel> model){
int[] result = namedParameterJdbcTemplate.batchUpdate("update query", SqlParameterSourceUtils.createBatch(model));
}
In my test class i am defining test method as
class MyTestClass{
#Mock
NamedParameterJdbcTemplate namedParameterJdbcTemplate;
#InjectMocks
MyDao dao;
#Test
public void testMyMethod() {
final int[] rowsAffected = new int[]{1,2};
when(namedParameterJdbcTemplate.batchUpdate(any(), SqlParameterSourceUtils.createBatch(Arrays.asList(anySet())))).thenReturn(rowsAffected);
List<MyModel> myModels = new ArrayList<>();
MyModel mymodel = new MyModel();
mymodel.setSomeParam("");
myModels.add(mymodel);
dao.myMethod(myModels);
}
}
While running this test method , i am getting NullPointerException in called method(myMethod()). int[] result is coming as null. My understanding is it should get the result from the stub in the mock.
Please help me understand what am i doing wrong.
It seems that you're not using the correct import for any() because if it would be the correct ArgumentMatchers.any() from Mockito, Mockito would complain that you don't use an ArgumentMatcher for both parameters of .batchUpdate().
You can statically import it with import static org.mockito.ArgumentMatchers.*; or use ArgumentMatchers.any().
So as first step, try the following:
when(namedParameterJdbcTemplate.batchUpdate(ArgumentMatchers.any(), ArgumentMatchers.any())).thenReturn(rowsAffected);
or be less generic and match the return type of SqlParameterSourceUtils.createBatch() with:
// I don't know what SqlParameterSourceUtils.createBatch() returns, so you might have to adjust it
when(namedParameterJdbcTemplate.batchUpdate(ArgumentMatchers.any(), ArgumentMatchers.eq("SOME RETURN"))).thenReturn(rowsAffected);
It worked by adding the cast to the Argument matchers:
Updated Code :
when(namedParameterJdbcTemplate.batchUpdate(anyString(), (SqlParameterSource[]) any())).thenReturn(rowsAffected);

Is a mock MongoRepository saving objects?

I am using SpringBoot 1.5.9 and try to do Integration testing. Weirdly a MongoRepository.save() method updates the object when called on mock MongoRepository.
I have a Counter Class
public class Counter {
public String id;
public int seq;
public void increaseSeq() {
this.seq += 1;
}
}
And his repository
public interface CounterRepository extends MongoRepository<Counter, String>{
Counter findById(String id);
List<Counter> findAll();
}
And his service
#Service
public class CounterService {
#Autowired private CounterRepository counterRepository;
public Counter findCounter(String id) {
return counterRepository.findById(id);
}
public int getSeqAndIncrease(String id) {
Counter counter = findCounter(id);
if (counter == null) {
return -1;
}
counter.increaseSeq();
counterRepository.save(counter);
return counter.getSeq();
}
}
Now, when I do system integration and try to mock the counterRepository, it happens something that I don't expect. The counterRepository.findById() returns a Counter object where the 'seq' field is increased. Why? Does the counterRepository.save() affect the result in any way (the counterRepository is mocked, hence I suppose that save() should not have any effect)?
#RunWith(SpringRunner.class)
#SpringBootTest
public class FlowServiceTest {
#MockBean private CounterRepository counterRepository;
#Autowired private CounterService counterService;
#Before
public void setUp() {
Mockito.when(counterRepository.save(any(Counter.class))).then(arg -> arg.getArgumentAt(0, Counter.class));
Mockito.when(counterRepository.findById("flow")).thenReturn(new Counter("flow", 10));
}
#Test
public void testSavingInDatabase() {
System.out.println(counterRepository.findById("flow"));
counterService.getSeqAndIncreaseSafe("flow");
System.out.println(counterRepository.findById("flow"));
counterService.getSeqAndIncreaseSafe("flow");
System.out.println(counterRepository.findById("flow"));
}
}
It prints "10 11 12". Why doesn't it print '10 10 10'?
The problem is these lines
counterRepository.save(counter);
return counter.getSeq();
What you should be doing is this
Counter saveCounter = counterRepository.save(counter);
return savedCounter.getSeq();
In getSeqAndIncrease method, you are not returning sequence of the saved object.
By doing this you are making your mock statement for save useless. Because you are not using the value returned from mock.
tl;dr - The returned object from mock is initialized only once in mockito. So I basically got the same reference every time, and since it is a reference not a new object, the values are updated.
Complete answer: When setting
Mockito.when(counterRepository.findById("flow")).thenReturn(new Counter("flow", 10));
, it might seem intuitive to return a new object every time, but the return object is initialised only once when the test starts and will be returned at all subsequent calls.
Then, in my code I do
counter.increaseSeq();
which increases the 'seq' of found object (this object comes from Mockito). Then at the next call, Mockito returns the firstly initialised object which was updated in the meantime; Mockito does not return a new object as it might seem like.

How specify the behaviour of SpringClassRule/SpringMethodRule for a specific #Test?

I am working with Spring 4.3.1.RELEASE and I have the following about testing:
#RunWith(Parameterized.class)
#ContextConfiguration(classes={RootApplicationContextConfig.class})
#Transactional
public class PersonaJdbcRepositoryTest {
#ClassRule
public static final SpringClassRule SPRING_CLASS_RULE= new SpringClassRule();
#Rule
public final SpringMethodRule springMethodRule = new SpringMethodRule();
#Autowired
private PersonaRepository personaJdbcRepository;
private final Persona persona;
public PersonaJdbcRepositoryTest(Persona persona){
this.persona = persona;
}
#Parameters
public static Collection<Persona[]> data() {
return Arrays.asList(new Persona[][] {
{PersonaFactory.crearPersona01()},
{PersonaFactory.crearPersona02()},
{PersonaFactory.crearPersona03()},
{PersonaFactory.crearPersona04()},
{PersonaFactory.crearPersonaMix()}
});
}
#Test
#Sql(scripts={"classpath:/com/manuel/jordan/h2/h2-elimination-script.sql"})
public void saveOneTest(){
Persona personaSaveOne = personaJdbcRepository.saveOne(persona);
Persona personaFindOne = personaJdbcRepository.findOne(personaSaveOne.getId());
assertEquals(personaFindOne, personaSaveOne);
}
#Test
public void findOneTest(){
Persona personaFindOne = personaJdbcRepository.findOne(persona.getId());
assertEquals(personaFindOne, persona);
}
#Test
public void findAllTest(){
Collection<Persona> personas = PersonaFactory.crearPersonas();
Collection<Persona> personasFindAll = personaJdbcRepository.findAll();
assertEquals(personas.size(), personasFindAll.size());
}
}
I can confirm that each #Test is executed and pass N times (in this case 5) according with data().
My requirement is that: I only need one execution of the findAllTest() method. I mean, it is executed 4 times unnecessarily. Even more when it does not use the persona object.
Therefore is possible indicate through SpringClassRule/SpringMethodRule that a #Test method just works once? How?
Is it possible to indicate through SpringClassRule/SpringMethodRule that a #Test method just runs once?
No. That is not possible.
The behavior you are experiencing has nothing to do with Spring.
It is the Parameterized runner that controls how many times a test method is executed.
If you don't want a test method to be parameterized, simply move it to a different test class that does not use the Parameterized runner.

How do I mock an autowired #Value field in Spring with Mockito?

I'm using Spring 3.1.4.RELEASE and Mockito 1.9.5. In my Spring class I have:
#Value("#{myProps['default.url']}")
private String defaultUrl;
#Value("#{myProps['default.password']}")
private String defaultrPassword;
// ...
From my JUnit test, which I currently have set up like so:
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration({ "classpath:test-context.xml" })
public class MyTest
{
I would like to mock a value for my "defaultUrl" field. Note that I don't want to mock values for the other fields — I'd like to keep those as they are, only the "defaultUrl" field. Also note that I have no explicit "setter" methods (e.g. setDefaultUrl) in my class and I don't want to create any just for the purposes of testing.
Given this, how can I mock a value for that one field?
You can use the magic of Spring's ReflectionTestUtils.setField in order to avoid making any modifications whatsoever to your code.
The comment from Michał Stochmal provides an example:
use ReflectionTestUtils.setField(bean, "fieldName", "value"); before invoking your bean method during test.
Check out this tutorial for even more information, although you probably won't need it since the method is very easy to use
UPDATE
Since the introduction of Spring 4.2.RC1 it is now possible to set a static field without having to supply an instance of the class. See this part of the documentation and this commit.
It was now the third time I googled myself to this SO post as I always forget how to mock an #Value field. Though the accepted answer is correct, I always need some time to get the "setField" call right, so at least for myself I paste an example snippet here:
Production class:
#Value("#{myProps[‘some.default.url']}")
private String defaultUrl;
Test class:
import org.springframework.test.util.ReflectionTestUtils;
ReflectionTestUtils.setField(instanceUnderTest, "defaultUrl", "http://foo");
// Note: Don't use MyClassUnderTest.class, use the instance you are testing itself
// Note: Don't use the referenced string "#{myProps[‘some.default.url']}",
// but simply the FIELDs name ("defaultUrl")
You can use this magic Spring Test annotation :
#TestPropertySource(properties = { "my.spring.property=20" })
see
org.springframework.test.context.TestPropertySource
For example, this is the test class :
#ContextConfiguration(classes = { MyTestClass.Config.class })
#TestPropertySource(properties = { "my.spring.property=20" })
public class MyTestClass {
public static class Config {
#Bean
MyClass getMyClass() {
return new MyClass ();
}
}
#Resource
private MyClass myClass ;
#Test
public void myTest() {
...
And this is the class with the property :
#Component
public class MyClass {
#Value("${my.spring.property}")
private int mySpringProperty;
...
I'd like to suggest a related solution, which is to pass the #Value-annotated fields as parameters to the constructor, instead of using the ReflectionTestUtils class.
Instead of this:
public class Foo {
#Value("${foo}")
private String foo;
}
and
public class FooTest {
#InjectMocks
private Foo foo;
#Before
public void setUp() {
ReflectionTestUtils.setField(Foo.class, "foo", "foo");
}
#Test
public void testFoo() {
// stuff
}
}
Do this:
public class Foo {
private String foo;
public Foo(#Value("${foo}") String foo) {
this.foo = foo;
}
}
and
public class FooTest {
private Foo foo;
#Before
public void setUp() {
foo = new Foo("foo");
}
#Test
public void testFoo() {
// stuff
}
}
Benefits of this approach: 1) we can instantiate the Foo class without a dependency container (it's just a constructor), and 2) we're not coupling our test to our implementation details (reflection ties us to the field name using a string, which could cause a problem if we change the field name).
You can also mock your property configuration into your test class
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration({ "classpath:test-context.xml" })
public class MyTest
{
#Configuration
public static class MockConfig{
#Bean
public Properties myProps(){
Properties properties = new Properties();
properties.setProperty("default.url", "myUrl");
properties.setProperty("property.value2", "value2");
return properties;
}
}
#Value("#{myProps['default.url']}")
private String defaultUrl;
#Test
public void testValue(){
Assert.assertEquals("myUrl", defaultUrl);
}
}
I used the below code and it worked for me:
#InjectMocks
private ClassABC classABC;
#Before
public void setUp() {
ReflectionTestUtils.setField(classABC, "constantFromConfigFile", 3);
}
Reference: https://www.jeejava.com/mock-an-autowired-value-field-in-spring-with-junit-mockito/
Also note that I have no explicit "setter" methods (e.g. setDefaultUrl) in my class and I don't want to create any just for the purposes of testing.
One way to resolve this is change your class to use Constructor Injection, that can be used for testing and Spring injection. No more reflection :)
So, you can pass any String using the constructor:
class MySpringClass {
private final String defaultUrl;
private final String defaultrPassword;
public MySpringClass (
#Value("#{myProps['default.url']}") String defaultUrl,
#Value("#{myProps['default.password']}") String defaultrPassword) {
this.defaultUrl = defaultUrl;
this.defaultrPassword= defaultrPassword;
}
}
And in your test, just use it:
MySpringClass MySpringClass = new MySpringClass("anyUrl", "anyPassword");
Whenever possible, I set the field visibility as package-protected so it can be accessed from the test class. I document that using Guava's #VisibleForTesting annotation (in case the next guy wonders why it's not private). This way I don't have to rely on the string name of the field and everything stays type-safe.
I know it goes against standard encapsulation practices we were taught in school. But as soon as there is some agreement in the team to go this way, I found it the most pragmatic solution.
Another way is to use #SpringBootTest annotation properties field.
Here we override example.firstProperty property:
#SpringBootTest(properties = { "example.firstProperty=annotation" })
public class SpringBootPropertySourceResolverIntegrationTest {
#Autowired private PropertySourceResolver propertySourceResolver;
#Test
public void shouldSpringBootTestAnnotation_overridePropertyValues() {
String firstProperty = propertySourceResolver.getFirstProperty();
String secondProperty = propertySourceResolver.getSecondProperty();
Assert.assertEquals("annotation", firstProperty);
Assert.assertEquals("defaultSecond", secondProperty);
}
}
As you can see It overrides only one property. Properties not mentioned in #SpringBootTest stay untouched. Therefore, this is a great solution when we need to override only specific properties for the test.
For single property you can write it without braces:
#SpringBootTest(properties = "example.firstProperty=annotation")
Answer from: https://www.baeldung.com/spring-tests-override-properties#springBootTest
I also encourage you to whenever possible pass property as a parameter in constructor like in Dherik answer (https://stackoverflow.com/a/52955459/1673775) as it enables you to mock properties easily in unit tests.
However in integration tests you often don't create objects manually, but:
you use #Autowired
you want to modify property used in a class that is used in your integration test indirectly as it is deep dependency of some directly used class.
then this solution with #SpringBootTest might be helpful.

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