I am trying to specific String value in mockito using when() method like
#Mock Individual indProvider;
when(indProvider.asProvider().getProviderId()).thenReturn("795316051750");
But I am getting exception
org.mockito.exceptions.misusing.InvalidUseOfMatchersException:
Invalid use of argument matchers!
0 matchers expected, 1 recorded.
This exception may occur if matchers are combined with raw values:
//incorrect:
someMethod(anyObject(), "raw String");
When using matchers, all arguments have to be provided by matchers.
For example:
//correct:
someMethod(anyObject(), eq("String by matcher"));
For more info see javadoc for Matchers class.
How can I return specific String in such case?
There's probably somewhere in the code a mockito Matcher used outside of stubbed invocation or verified invocation.
If your code base use JUnit I recommend the use of the mockito runner, it will validate the mockito use for each test method, which means any issue can be pinpointed to the test incorrectly written.
#RunWith(MockitoJUnitRunner.class)
public class TheTest {
#Test public void shoudl_perform_something() { ... }
}
Or with a mockito rule (since 1.10.17)
public class TheTest {
#Rule MockitoRule mockitoRule = MockitoJUnit.rule();
#Test public void should_perform_something() { ... }
}
You don't have to use have #Mocks in your test to benefit from this framework validation.
And anyway both are the preferred ways to instantiate mocks compared to MockitoAnnotations.initMocks(...)
Also which version of mockito are you using ? I believe Mockito has improved some messages with the location of the bad code.
Note that this code cannot work properly, because indProvider.asProvider() is not stubbed so mockito will use the default value which is null. You have to do this either way (deep stubs is here for legacy code, a mock returning a mock is usually considered a code smell and it shows the tested code breaks the Law of Demeter) :
#Mock(answer = RETURNS_DEEP_STUBS) Individual indProvider;
// ...
when(indProvider.asProvider().getProviderId()).thenReturn("795316051750");
or as answered by #przemek, it's more verbose and shows the same weakness in the tested code.
#Mock(answer = RETURNS_DEEP_STUBS) Individual indProvider;
#Mock Provider provider;
// ...
when(indProvider.asProvider()).thenReturn(provider);
when(provider.getProviderId()).thenReturn("795316051750");
I advise you to read this book (Growing Object Oriented Software Guided by Tests), it's one of the very best book you can read about writing softwares guided by tests. I find it even more important than infamous Effective Java book.
You should use multiple when() interceptions:
#Mock Individual indProvider;
#Mock Provider provider;
when(indProvider.asProvider()).thenReturn(provider);
when(provider.getProviderId()).thenReturn("795316051750");
You can solve it like this:
Mockito.when(indProvider.asProvider().getProviderId())
.thenAnswer(t -> "795316051750");
Related
I am using RandomStringUtils class from apache commons lang3 library. I am facing issue while mocking the random method of it.
below is my example class with simple method generatePassword.
public class Example() {
public String generatePassword() {
final String randomDevicePass = RandomStringUtils.random(10, "abcdefghijklmnopqrstuvwxyz");
System.out.println(randomDevicePass)
return randomDevicePass;
}
}
below is my Test Class, by which I am running the test case.
#RunWith(MockitoJUnitRunner.class)
public class ExampleTest() {
#InjectMocks
private Example Example;
#Mock
RandomStringutils randomStringutils;
#Test
public void givenCharacters_returnStringPassword() {
Mockito.when(randomStringUtils.random(Mockito.anyInt(),Mockito.anyString())).thenReturn("asdf");
Assertions.assertEquals("asdf", example.generatePassword());
}
}
It gives below error:
Misplaced or misused argument matcher detected here:
You cannot use argument matchers outside of verification or stubbing.
Examples of correct usage of argument matchers:
when(mock.get(anyInt())).thenReturn(null);
doThrow(new RuntimeException()).when(mock).someVoidMethod(anyObject());
verify(mock).someMethod(contains("foo"))
This message may appear after an NullPointerException if the last matcher is returning an object
like any() but the stubbed method signature expect a primitive argument, in this case,
use primitive alternatives.
when(mock.get(any())); // bad use, will raise NPE
when(mock.get(anyInt())); // correct usage use
Also, this error might show up because you use argument matchers with methods that cannot be mocked.
Following methods *cannot* be stubbed/verified: final/private/equals()/hashCode().
Mocking methods declared on non-public parent classes is not supported.
org.mockito.exceptions.misusing.InvalidUseOfMatchersException:
Misplaced or misused argument matcher detected here:
I am not sure how to mock the Java inbuilt apache commons library class. not sure can we use spy? or something ...can anyone helps me on this ?
Thanks in advance
It is usually somewhat of a code smell whenever you need to mock a static method. However, there are ways of doing it within the Mockito library.
First, add a file to your test resources directory in a new folder mockito-extensions. The file name should be org.mockito.plugins.MockMaker. The file needs to have the single line: mock-maker-inline
Then you are ready to add a static mock through Mockito.mockStatic like this:
try (MockedStatic<RandomStringUtils> utils = Mockito.mockStatic(RandomStringUtils.class)) {
utils.when(() -> RandomStringUtils.random(Mockito.anyInt(), Mockito.anyString())).thenReturn("asdf");
Assertions.assertEquals("asdf", example.generatePassword());
}
I am recently writing a JUnit test and I acknowledged that Mockito either needs all Raw values or using all Matchers but I find the following case still fails with all Matchers, error message is:
Invalid use of argument matchers!
0 matchers expected, 1 recorded:
I tested a little bit and it looks like something to do with using a stub method as value for the eq() Matcher. See example below:
I have a Class A very simple
public class A {
public void testMockitoMatcher(double a, String b){
}
}
Here is my test case
import org.junit.Test;
import static org.mockito.Mockito.*;
public class SomeUnitTest {
private A mockA = mock(A.class);
#Test
public void allMatchersDoesntWork() {
Object mockObject = mock(Object.class);
String someString = "Just some mocked String value to return";
when(mockObject.toString()).thenReturn(someString);
mockA.testMockitoMatcher(1312d, mockObject.toString());
verify(mockA, times(1)).testMockitoMatcher(anyDouble(), eq(someString)); //<- This works
verify(mockA, times(1)).testMockitoMatcher(anyDouble(), eq(mockObject.toString())); //<- This doesn't by using stub method toString() to return the String value as param to eq()
}
}
I also verified by using debug at 2nd verify statement that mockObject.toString() can still return the stubbed value for me. Also both verify use all Matchers, why mockito still gives me only 1 Matchers recorded instead of 2 at the 2nd verify?
Thanks!
Mockito expects your tests to be in three stages.
You set things up for the test, including stubbing any methods that need to be stubbed (the "arrange" stage).
You run the actual method that you're trying to test (the "act" stage).
You make assertions about the output of the test, possibly including verifying which methods got called on your mocks (the "assert" stage).
You need to do these three things, in this sequence, because Mockito tracks whether you're stubbing, verifying or whatever. It also has its own internal stack which stores Matchers, for use in stubbing or verification.
In your second verify call in your example, the call to anyDouble() puts the Matcher onto the stack. But this creates an invalid state for the call to mockObject.toString().
Don't do this. Once you're ready to run your assertions and verifications, you shouldn't be making any more calls to stubbed methods. Keep the "arrange", "act" and "assert" stages of each test entirely separate from each other.
I've recently started using Mockito 3 + Junit 5 + Spring 5 and I'm writing some example tests in order to understand how Mockito works. I have a question about inner calls. So, I have a spring component A in which is injected some DAO component someObjectDAO. The A class:
#Component("aClass")
public class A {
#Autowired
private ObjectDAO someObjectDAO;
public Long countRecords() {
ObjectSearchCriteria search = new ObjectSearchCriteria();
return someObjectDAO.count(search);
}
}
I want to test A's countRecords method. I've mocked and injected someObjectDAO like this:
#ExtendWith(MockitoExtension.class)
#ContextConfiguration("contextConfFileSomewhere")
public class ATest {
#Mock
ObjectDAO someObjectDAOMock;
#InjectMocks
A aComponent;
#Test
void testCount() {
ObjectSearchCriteria search = Mockito.mock(ObjectSearchCriteria.class);
Mockito.when(someObjectDAOMock.count(search)).thenReturn(1L);
Assertion.assertEquals(1L, aComponent.countRecords());
}
}
But this way is incorrect, in fact PotentialStubbingProblem is raised.
org.mockito.exceptions.misusing.PotentialStubbingProblem:
Strict stubbing argument mismatch. Please check:
- this invocation of 'count' method:
someObjectDAO.count(
com.example.java.ObjectSearchCriteria#45cc6b13
);
-> at com.example.java.A.countRecords()
- has following stubbing(s) with different arguments:
1. someObjectDAOMock.count(
Mock for ObjectSearchCriteria, hashCode: 204078646
);
Typically, stubbing argument mismatch indicates user mistake when writing tests.
Mockito fails early so that you can debug potential problem easily.
However, there are legit scenarios when this exception generates false negative signal:
- stubbing the same method multiple times using 'given().will()' or 'when().then()' API
Please use 'will().given()' or 'doReturn().when()' API for stubbing.
- stubbed method is intentionally invoked with different arguments by code under test
Please use default or 'silent' JUnit Rule (equivalent of Strictness.LENIENT).
For more information see javadoc for PotentialStubbingProblem class.
If I understand correctly the exception indicates that I'm passing an object different from the actual object used in the code under test, right?
So, how can I mock a inner method which uses a local variable as parameter?
You want to mock the call to ObjectDAO.count which has parameters. Instead of passing an instance of the expected parameter as an argument, you should use an argument matcher:
Mockito.when(someObjectDAOMock.count(Mockito.any(ObjectSearchCriteria.class)))
.thenReturn(1L);
Edit: You should probably never even want to "mock a local variable". Your goal is to test the system under test (countRecords method) without knowing implementation details. All you can do is mock the dependencies.
I try to simulate the behaviour of a class, using Mockito.
This worked using Mockito 1.x. Migrating to JUnit 5 and Mockito 2 it seems not to work anymore.
#ExtendWith(MockitoExtension.class)
public class MockitoExample {
static abstract class TestClass {
public abstract int booleanMethod(boolean arg);
}
#Mock
TestClass testClass;
#BeforeEach
public void beforeEach() {
when(testClass.booleanMethod(eq(true))).thenReturn(1);
when(testClass.booleanMethod(eq(false))).thenReturn(2);
}
#Test
public void test() {
assertEquals(1,testClass.booleanMethod(true));
assertEquals(2,testClass.booleanMethod(false));
}
}
The expectation is, that the mocked TestClass shows the behaviour as tested in the test-method.
The error I get is:
org.mockito.exceptions.misusing.PotentialStubbingProblem:
Strict stubbing argument mismatch. Please check:
- this invocation of 'booleanMethod' method:
testClass.booleanMethod(false);
-> at org.oneandone.ejbcdiunit.mockito_example.MockitoExample.beforeEach(MockitoExample.java:30)
- has following stubbing(s) with different arguments:
1. testClass.booleanMethod(false);
-> at org.oneandone.ejbcdiunit.mockito_example.MockitoExample.beforeEach(MockitoExample.java:29)
Typically, stubbing argument mismatch indicates user mistake when writing tests.
Mockito fails early so that you can debug potential problem easily.
However, there are legit scenarios when this exception generates false negative signal:
- stubbing the same method multiple times using 'given().will()' or 'when().then()' API
Please use 'will().given()' or 'doReturn().when()' API for stubbing.
- stubbed method is intentionally invoked with different arguments by code under test
Please use default or 'silent' JUnit Rule (equivalent of Strictness.LENIENT).
For more information see javadoc for PotentialStubbingProblem class.
In both cases, the argument false seems to be matched, though I clearly matched with true.
Is that a bug in Mockito 2.17 or a misunderstanding. How should/can I use Mockito 2.x to simulate calls with different boolean arguments?
The example can also be found on github. But surefire will start the test only using
mvn test -Dtest=MockitoExample
Executing the test using Mockito 2.21 leads to the same results.
Since Mockito 2.20 it is also possible, to add lenient() locally
#ExtendWith(MockitoExtension.class)
public class MockitoExample {
static abstract class TestClass {
public abstract int booleanMethod(boolean arg);
}
#Mock
TestClass testClass;
#BeforeEach
public void beforeEach() {
lenient().when(testClass.booleanMethod(eq(true))).thenReturn(1);
lenient().when(testClass.booleanMethod(eq(false))).thenReturn(2);
}
#Test
public void test() {
assertEquals(1,testClass.booleanMethod(true));
assertEquals(2,testClass.booleanMethod(false));
}
}
With strict stubs (the default behavior of Mockito) calling several whens on the same method will reset that mock. The solution is to call when once and have the logic in an Answer:
#BeforeEach
public void beforeEach() {
when(testClass.booleanMethod(anyBoolean())).thenAnswer(invocationOnMock -> {
if ((boolean) invocationOnMock.getArguments()[0]) {
return 1;
}
return 2;
});
}
Alternatively, you can use lenient mocking, but that's not always a good idea - lenient mocking allows redundant stubbing, and makes it easier for you to make mistakes in your test, which may lead to unnoticed bugs in the "production" code:
#ExtendWith(MockitoExtension.class)
#MockitoSettings(strictness = Strictness.LENIENT)
public class MockitoExample {
Mockito 1 and 2 don't have the same "strictness" level.
Besides by using Mockito 2 with JUnit 4 or 5 the default level will be still different.
To sum up :
3 levels of strictness :
LENIENT : minimum strictness
WARN : extra warnings emitted to the console
STRICT_STUBS : ensures clean tests by throwing exception if potential misuse but may also produce some false positives.
Default effective level according to the APIs used :
Mockito 1 : LENIENT
Mockito 2 with JUnit 4 : WARN
Mockito 2 with JUnit 5 (MockitoExtension.class) : STRICT_STUBS
Mockito 3 : planned to be STRICT_STUBS.
More details
The actual Mockito documentation is very clear about that :
The Strictness javadoc states :
Configures the "strictness" of Mockito during a mocking session.A
session typically maps to a single test method invocation. Strictness
drives cleaner tests and better productivity.The easiest way to
leverage enhanced Strictness is usingMockito's JUnit support
(MockitoRule or MockitoJUnitRunner).If you cannot use JUnit support
MockitoSession is the way to go.
How strictness level influences the behavior of the test (mocking
session)?
1.Strictness.LENIENT - no added behavior.The default of Mockito 1.x.Recommended only if you cannot use STRICT_STUBS nor WARN.
2.Strictness.WARN - helps keeping tests clean and improves debuggability.Reports console warnings about unused stubsand stubbing
argument mismatch (see org.mockito.quality.MockitoHint).The default
behavior of Mockito 2.x when JUnitRule or MockitoJUnitRunner are used.
Recommended if you cannot use STRICT_STUBS.
3.Strictness.STRICT_STUBS - ensures clean tests, reduces test code duplication, improves debuggability.Best combination of flexibility
and productivity. Highly recommended.Planned as default for Mockito
v3.See STRICT_STUBS for the details.
But whatever the thrown exception associated to the message
"has following stubbing(s) with different arguments"
seems to be a excessively strict check.
The exception message proves that in a some way :
However, there are legit scenarios when this exception generates false
negative signal:
...
stubbed method is intentionally invoked with different arguments by code under test
So forbidding it by default seems to be too much.
So if you use JUnit 5, as alternative to STRICT_STUBS you could use WARNING but you generally want to avoid LENIENT that is too quiet.
In addition to MockitoExtension, the mockito-junit-jupiter library provides
#MockitoSettings that may be used at the method level as well as at the class level.
Here is an example :
import java.util.List;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.Mockito;
import org.mockito.junit.jupiter.MockitoExtension;
import org.mockito.junit.jupiter.MockitoSettings;
import org.mockito.quality.Strictness;
#ExtendWith(MockitoExtension.class)
public class FooTest {
#MockitoSettings(strictness = Strictness.WARN)
#Test
void foo() throws Exception {
List<String> strings = Mockito.mock(List.class);
Mockito.when(strings.add("a"))
.thenReturn(true);
Mockito.when(strings.add("b"))
.thenReturn(false);
}
#Test
void fooKo() throws Exception {
List<String> strings = Mockito.mock(List.class);
Mockito.when(strings.add("a"))
.thenReturn(true);
Mockito.when(strings.add("b"))
.thenReturn(false);
}
}
fooKo() throws the misuse Mockito exception while foo() is successful but provides helpful warnings :
[MockitoHint] FooTest (see javadoc for MockitoHint):
[MockitoHint] 1. Unused -> at FooTest.foo(FooTest.java:19)
[MockitoHint] 2. Unused -> at FooTest.foo(FooTest.java:21)
As other alternative you can also use Mockito.lenient() very well described by
aschoerk to apply the lenient strictness for a specific invocation.
As well as you can set every mock invocations as lenient at the mock instantiation :
#Test
void foo() throws Exception {
List<String> strings = Mockito.mock(List.class, Mockito.withSettings()
.lenient());
....
}
Since the first answer came as a surprise, I checked the following:
interface Poops {
String get(boolean is);
}
#Test
void test1() {
Poops a = mock(Poops.class);
when(a.get(eq(true))).thenReturn("1");
when(a.get(eq(false))).thenReturn("2");
Assertions.assertEquals("1", a.get(true));
Assertions.assertEquals("2", a.get(false));
}
It works with Mockito 2.21.0.
Update:
The problem seems to be the Jupiter Mockito extension which changes the default setting to Strictness.STRICT_STUBS.
My Code is as below,
#RunWith(MockitoJUnitRunner.class)
public class MyClass {
private static final String code ="Test";
#Mock
private MyClassDAO dao;
#InjectMocks
private MyClassService Service = new MyClassServiceImpl();
#Test
public void testDoSearch() throws Exception {
final String METHOD_NAME = logger.getName().concat(".testDoSearchEcRcfInspections()");
CriteriaDTO dto = new CriteriaDTO();
dto.setCode(code);
inspectionService.searchEcRcfInspections(dto);
List<SearchCriteriaDTO> summaryList = new ArrayList<SearchCriteriaDTO>();
inspectionsSummaryList.add(dto);
when(dao.doSearch(dto)).thenReturn(inspectionsSummaryList);//got error in this line
verify(dao).doSearchInspections(dto);
}
}
I am getting below exception
org.mockito.exceptions.misusing.UnnecessaryStubbingException:
Unnecessary stubbings detected in test class: Test
Clean & maintainable test code requires zero unnecessary code.
Following stubbings are unnecessary (click to navigate to relevant line of code):
1. -> at service.Test.testDoSearch(Test.java:72)
Please remove unnecessary stubbings or use 'silent' option. More info: javadoc for UnnecessaryStubbingException class.
at org.mockito.internal.exceptions.Reporter.formatUnncessaryStubbingException(Reporter.java:838)
at org.mockito.internal.junit.UnnecessaryStubbingsReporter.validateUnusedStubs(UnnecessaryStubbingsReporter.java:34)
at org.mockito.internal.runners.StrictRunner.run(StrictRunner.java:49)
at org.mockito.junit.MockitoJUnitRunner.run(MockitoJUnitRunner.java:103)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Please help me how to resolve
At first you should check your test logic. Usually there are 3 cases. First, you are mocking the wrong method (you made a typo or someone changed tested code so that mocked method is no longer used). Second, your test is failing before this method is called. Third, your logic falls in wrong if/switch branch somewhere in the code so that mocked method is not called.
If this is the first case you always want to change the mocked method for the one used in the code. With the second and the third it depends. Usually you should just delete this mock if it has no use. But sometimes there are certain cases in parametrized tests, which should take this different path or fail earlier. Then you can split this test into two or more separate ones but that's not always good looking. 3 test methods with possibly 3 arguments providers can make your test look unreadable. In that case for JUnit 4 you silent this exception with either
#RunWith(MockitoJUnitRunner.Silent.class)
annotation or if you are using rule approach
#Rule
public MockitoRule rule = MockitoJUnit.rule().strictness(Strictness.LENIENT);
or (the same behaviour)
#Rule
public MockitoRule rule = MockitoJUnit.rule().silent();
For JUnit 5 tests you can silence this exception using this annotation provided in mockito-junit-jupiter package:
#ExtendWith(MockitoExtension.class)
#MockitoSettings(strictness = Strictness.LENIENT)
class JUnit5MockitoTest {
}
Replace #RunWith(MockitoJUnitRunner.class) with #RunWith(MockitoJUnitRunner.Silent.class).
For me neither the #Rule nor the #RunWith(MockitoJUnitRunner.Silent.class) suggestions worked. It was a legacy project where we upgraded to mockito-core 2.23.0.
We could get rid of the UnnecessaryStubbingException by using:
Mockito.lenient().when(mockedService.getUserById(any())).thenReturn(new User());
instead of:
when(mockedService.getUserById(any())).thenReturn(new User());
Needless to say that you should rather look at the test code, but we needed to get the stuff compiled and the tests running first of all ;)
Silent is not a solution. You need fix your mock in your test. See official documentation here.
Unnecessary stubs are stubbed method calls that were never realized during test execution (see also MockitoHint), example:
//code under test:
...
String result = translator.translate("one")
...
//test:
...
when(translator.translate("one")).thenReturn("jeden"); // <- stubbing realized during code execution
when(translator.translate("two")).thenReturn("dwa"); // <- stubbing never realized
...
Notice that one of the stubbed methods were never realized in the code under test, during test execution. The stray stubbing might be an oversight of the developer, the artifact of copy-paste or the effect not understanding the test/code. Either way, the developer ends up with unnecessary test code. In order to keep the codebase clean & maintainable it is necessary to remove unnecessary code. Otherwise tests are harder to read and reason about.
To find out more about detecting unused stubbings see MockitoHint.
when(dao.doSearch(dto)).thenReturn(inspectionsSummaryList);//got error in this line
verify(dao).doSearchInspections(dto);
The when here configures your mock to do something. However, you donot use this mock in any way anymore after this line (apart from doing a verify). Mockito warns you that the when line therefore is pointless. Perhaps you made a logic error?
Replace
#RunWith(MockitoJUnitRunner.class)
with
#RunWith(MockitoJUnitRunner.Silent.class)
or remove #RunWith(MockitoJUnitRunner.class)
or just comment out the unwanted mocking calls (shown as unauthorised stubbing).
This was already pointed out in this comment, but I think that's too easy to overlook: You may run into an UnnecessaryStubbingException if you simply convert a JUnit 4 test class to a JUnit 5 test class by replacing an existing #Before with #BeforeEach, and if you perform some stubbing in that setup method that is not realized by at least one of the test cases.
This Mockito thread has more information on that, basically there is a subtle difference in the test execution between #Before and #BeforeEach. With #Before, it was sufficient if any test case realized the stubbings, with #BeforeEach, all cases would have to.
If you don't want to break up the setup of #BeforeEach into many small bits (as the comment cited above rightly points out), there's another option still instead of activating the lenient mode for the whole test class: you can merely make those stubbings in the #BeforeEach method lenient individually using lenient().
As others pointed out it is usually the simplest to remove the line that is unnecessarily stubbing a method call.
In my case it was in a #BeforeEach and it was relevant most of the time. In the only test where that method was not used I reset the mock, e.g.:
myMock.reset()
Hope this helps others with the same problem.
(Note that if there are multiple mocked calls on the same mock this could be inconvenient as well since you'll have to mock all the other methods except the one that isn't called.)
Looking at a part of your stack trace it looks like you are stubbing the dao.doSearch() elsewhere. More like repeatedly creating the stubs of the same method.
Following stubbings are unnecessary (click to navigate to relevant line of code):
1. -> at service.Test.testDoSearch(Test.java:72)
Please remove unnecessary stubbings or use 'silent' option. More info: javadoc for UnnecessaryStubbingException class.
Consider the below Test Class for example:
#RunWith(MockitoJUnitRunner.class)
public class SomeTest {
#Mock
Service1 svc1Mock1;
#Mock
Service2 svc2Mock2;
#InjectMock
TestClass class;
//Assume you have many dependencies and you want to set up all the stubs
//in one place assuming that all your tests need these stubs.
//I know that any initialization code for the test can/should be in a
//#Before method. Lets assume there is another method just to create
//your stubs.
public void setUpRequiredStubs() {
when(svc1Mock1.someMethod(any(), any())).thenReturn(something));
when(svc2Mock2.someOtherMethod(any())).thenReturn(somethingElse);
}
#Test
public void methodUnderTest_StateUnderTest_ExpectedBehavior() {
// You forget that you defined the stub for svcMock1.someMethod or
//thought you could redefine it. Well you cannot. That's going to be
//a problem and would throw your UnnecessaryStubbingException.
when(svc1Mock1.someMethod(any(),any())).thenReturn(anyThing);//ERROR!
setUpRequiredStubs();
}
}
I would rather considering refactoring your tests to stub where necessary.
Well, In my case Mockito error was telling me to call the actual method after the when or whenever stub. Since we were not invoking the conditions that we just mocked, Mockito was reporting that as unnecessary stubs or code.
Here is what it was like when the error was coming :
#Test
fun `should return error when item list is empty for getStockAvailability`() {
doAnswer(
Answer<Void> { invocation ->
val callback =
invocation.arguments[1] as GetStockApiCallback<StockResultViewState.Idle, StockResultViewState.Error>
callback.onApiCallError(stockResultViewStateError)
null
}
).whenever(stockViewModelTest)
.getStockAvailability(listOf(), getStocksApiCallBack)
}
then I just called the actual method mentioned in when statement to mock the method.
changes done is as below
stockViewModelTest.getStockAvailability(listOf(), getStocksApiCallBack)
#Test
fun `should return error when item list is empty for getStockAvailability`() {
doAnswer(
Answer<Void> { invocation ->
val callback =
invocation.arguments[1] as GetStockApiCallback<StockResultViewState.Idle, StockResultViewState.Error>
callback.onApiCallError(stockResultViewStateError)
null
}
).whenever(stockViewModelTest)
.getStockAvailability(listOf(), getStocksApiCallBack)
//called the actual method here
stockViewModelTest.getStockAvailability(listOf(), getStocksApiCallBack)
}
it's working now.
If you're using this style instead:
#Rule
public MockitoRule rule = MockitoJUnit.rule().strictness(Strictness.STRICT_STUBS);
replace it with:
#Rule
public MockitoRule rule = MockitoJUnit.rule().silent();
I had UnnecessaryStubbingException when I tried to use the when methods on a Spy object.
Mockito.lenient() silenced the exception but the test results were not correct.
In case of Spy objects, one has to call the methods directly.
#ExtendWith(MockitoExtension.class)
#RunWith(JUnitPlatform.class)
class ArithmTest {
#Spy
private Arithm arithm;
#Test
void testAddition() {
int res = arithm.add(2, 5);
// doReturn(7).when(arithm).add(2, 5);
assertEquals(res, 7);
}
}
In case of a large project, it's difficult to fix each of these exceptions. At the same time, using Silent is not advised. I have written a script to remove all the unnecessary stubbings given a list of them.
https://gist.github.com/cueo/da1ca49e92679ac49f808c7ef594e75b
We just need to copy-paste the mvn output and write the list of these exceptions using regex and let the script take care of the rest.
If you use any() when mocking, you have to relpace #RunWith(MockitoJUnitRunner.class) with
#RunWith(MockitoJUnitRunner.Silent.class).