Error in Parameterised test cases in Junit - junit

I am trying to write a parameterized test case in JUnit. My code looks like this:
#RunWith(Parameterized.class)
#PrepareForTest({AR9DirectDebitFileWriterCustomization.class})
public class AR9DirectDebitFileWriterCustomizationTest2 extends AR3BasicUnitTest {
private DirectDebitExtractDetRec mockObj;
private ARApplicationContext mockAppCon;
private AR9DirectDebitFileWriterCustomization spyObj = null;
AccountDBViewData mockdbData;
AccountDBView mockdbView;
SearchInvoicesDBViewData[] mocksearchInvdbviewdatarr = new SearchInvoicesDBViewData[1];
#Before
public void setUp() throws Exception {
AR9DirectDebitFileWriterCustomization ar9Obj = new AR9DirectDebitFileWriterCustomization(mockdbView, mocksearchInvdbviewdatarr, mockdbData);
spyObj = PowerMockito.spy(ar9Obj);
}
public AR9DirectDebitFileWriterCustomizationTest2(DirectDebitExtractDetRec mockObj_from_collection, ARApplicationContext mockAppCon_from_collection) {
this.mockObj = mockObj_from_collection;
this.mockAppCon = mockAppCon_from_collection;
}
#Parameterized.Parameters
public static Collection<Object[]> getparameters() throws ACMException{
return Arrays.asList(new Object[][]{
{mock(DirectDebitExtractDetRec.class),mock(ARApplicationContext.class)}
});
}
#Test
#Parameters
public final void testAddFileRecordCustObjectARApplicationContext( ) throws Exception {
.....SOME CODE
}
Whenever I right click on the testAddFileRecordCustObjectARApplicationContext function and run it as Junit test I get an initialization error :
java.lang.Exception: No tests found matching Method
testAddFileRecordCustObjectARApplicationContext(amdocs.ar.customizationexits.handlers.helpers.AR9DirectDebitFileWriterCustomizationTest2)
from org.junit.internal.requests.ClassRequest#3fa50b at
org.junit.internal.requests.FilterRequest.getRunner(FilterRequest.java:37)
at
org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.(JUnit4TestReference.java:33)
at
org.eclipse.jdt.internal.junit4.runner.JUnit4TestMethodReference.(JUnit4TestMethodReference.java:25)
at
org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createTest(JUnit4TestLoader.java:54)
at
org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.loadTests(JUnit4TestLoader.java:38)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:452)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
After looking for several hours on internet about this issue I could not find anything meaningful. In this scenario I am using spy and powerMocktio Functionality as well.I am not sure what is the root of this error .
And interesting thing is when I run it without using Parameterised test ,it works perfectly fine.

I had very similar error:
No tests found matching data with any parameter from...
According to my observations, it is caused by another strange error:
Unable to mock class ... due to a missing dependency
Only the first I see when I run the test, and the second, when I debug it. According to https://stackoverflow.com/a/23788935/715269,
https://stackoverflow.com/a/25659518/715269, it is the bug connected to classpath reading. The problem disappears, when we upgrade JMockit to higher versions.

Related

Mock a void method

//Original method:
#Autowired
private ConversionServiceValidator validator;
public CRSConversionResult convertCRS(ConvertCrsVo convertCrsVo) throws Exception {
if (validator.isSameSourceAndTarget(convertCrsVo))
throw new ValidationException(Constants.BADREQUEST);
if (convertCrsVo.getPreferredTransforms() != null) {
List<TransformVo> preferredTransformList = new ArrayList<>();
for (TransformVo transformVo : convertCrsVo.getPreferredTransforms()) {
preferredTransformList.add(getPerfByCode(transformVo));
}
convertCrsVo.setPreferredTransforms(preferredTransformList);
}
convertCrsVo.setSourceCRS(getCrsVoByCode(convertCrsVo.getSourceCRS()));
convertCrsVo.setTargetCRS(getCrsVoByCode(convertCrsVo.getTargetCRS()));
convertCrsVo = validator.replaceCoordinates(convertCrsVo);
logger.info("ShellGeodeticService::convertCRS::Request to GeoCalService convertpoints::" + mapper.writeValueAsString(convertCrsVo));
ConvertPointsResponse response = geoCalService.convertCRS(convertCrsVo);
CRSConversionResult result = new CRSConversionResult();
result.setCriteriaMessage(response.getCriteriaMessage());
result.setResultPoints(response.getResultPoints());
result.setTransformName(response.getTransformName());
result.setTransformDescription(response.getTransformDescription());
// added schema as per pbi 195298
List<ConvertedTransformsResult> transformsResults = new ArrayList<>();
if (response.getTransforms() != null || !response.getTransforms().isEmpty())
response.getTransforms().stream().forEach(
t -> transformsResults.add(new ConvertedTransformsResult().getConvertedTransformsResult(t)));
result.setTransforms(transformsResults);
String logmessage=generateLogMessage(result,convertCrsVo);
logger.info(logmessage);
validator.isResponseValid(result);
return result;
}
//The testcase for the above method
#Test
public void testconvertCRSJob() throws Exception{
ConvertCrsVo convertCrsVo = TestDataFactory.getConvertCrsVo();
CRSConversionResult crsConversionResult = TestDataFactory.getCRSConversionResult();
ConversionServiceValidator conversionServiceValidatorMock = mock(ConversionServiceValidator.class);
Mockito.when(geoCalService.convertCRS(Mockito.any()))
.thenReturn(TestDataFactory.getConvertPointsResponse(convertCrsVo));
Mockito.when(validator.replaceCoordinates(convertCrsVo))
.thenReturn(TestDataFactory.getConvertCrsVo());
Mockito.when(geoCalService.search(Mockito.any(SearchFilter.class)))
.thenReturn(TestDataFactory.getSearchResultResponseForCRS());
Mockito.when(shellGeodeticService.convertCRS(convertCrsVo))
.thenReturn(TestDataFactory.getCRSConversionResult());
shellGeodeticService.convertCRSJob();
}
The error that i am getting is as below:
org.mockito.exceptions.misusing.CannotStubVoidMethodWithReturnValue:
'isResponseValid' is a void method and it cannot be stubbed with a return value!
Voids are usually stubbed with Throwables:
doThrow(exception).when(mock).someVoidMethod();
If you're unsure why you're getting above error read on.
Due to the nature of the syntax above problem might occur because:
1. The method you are trying to stub is overloaded. Make sure you are calling the right overloaded version.
2. Somewhere in your test you are stubbing final methods. Sorry, Mockito does not verify/stub final methods.
3. A spy is stubbed using when(spy.foo()).then() syntax. It is safer to stub spies -
- with doReturn|Throw() family of methods. More in javadocs for Mockito.spy() method.
4. Mocking methods declared on non-public parent classes is not supported.
at com.shell.geodetic.GeodeticConvertionApiAppTests.testconvertCRSJob(GeodeticConvertionApiAppTests.java:1783)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
Can someone help me on how to stub the void method "isResponseValid" ? I tried around 100 combinations that i saw in SOF and nothing worked. Thanks for the help in advance.
*Edit
Class ConversionServiceValidator {
public void isResponseValid(CRSConversionResult response) throws InvalidDataException {
if (response.getResultPoints().isEmpty() || response.getResultPoints() == null) {
throw new ValidationException("Request body has incorrect format");
} else {
for (Point point : response.getResultPoints()) {
if (point.getX().trim().equals("0") || point.getY().trim().equals("0")) {
throw new InvalidDataException(400, "Bad Request", "WARNING: Not all points could be converted",
response);
}
}
}
It is a mock #InjectMocks ShellGeodeticService shellGeodeticService;
shellGeodeticService is not a mock. #InjectMocks is used for the class under test, where the mocks are injected into.
That implies you can not use
Mockito.when(shellGeodeticService.convertCRS(convertCrsVo))
.thenReturn(TestDataFactory.getCRSConversionResult());
in your test as only mocks(or spys) can be used within Mockito.when.
Actually im trying to run test case for shellGeodeticService.convertCRS() and since it calls isResponseValid method internally , i have to mock that also right?
No, that is incorrect. If validator is a mock every method invocation will do nothing by default. So, unless you want to throw an exception, you do not need to define anything.
As your question lacks some details, I assume a complete version of your test could be similiar to this:
#InjectMocks
ShellGeodeticService shellGeodeticService;
#Mock
ConversionServiceValidator validator;
#Mock
... geoCalService; // some unknown class
#Test
public void testconvertCRSJob() throws Exception{
ConvertCrsVo convertCrsVo = TestDataFactory.getConvertCrsVo();
// Note sure whether this is correct by your logic as there is no `replacement` happening.
Mockito.when(validator.replaceCoordinates(convertCrsVo)).thenReturn(convertCrsVo);
Mockito.when(geoCalService.convertCRS(Mockito.any())).thenReturn(TestDataFactory.getConvertPointsResponse(convertCrsVo));
CRSConversionResult result = shellGeodeticService.convertCRS();
// do some assertions on the result
}
As validator is a mock:
validator.isSameSourceAndTarget(convertCrsVo) returns false be default
validator.isResponseValid( ... ) does nothing by default
As you did not add the methods getCrsVoByCode, getPerfByCode and generateLogMessage take note that if there are any further interactions with the mocked objects you'll need to add them.
(eg.: a call to geoCalService.search is not visible in your test code, so I removed the behaviour definition from the test displayed above)

Unable to Mock functions inside static method Powermock

I am writing unit test for the below code using junit and mockito
public class Abc implements Runnable
{
private static ServerSocket server;
private static int port;
public Abc(int cPort)
{
port = cPort;
}
public void run()
{
init();
}
public static void init()
{
try {
server = new ServerSocket(port);
...something...
client.close();
}
}
catch(IOException e)
{
System.out.println("Exception inside init()...");
e.printStackTrace();
}
}
};
Unit test I have written
#RunWith(PowerMockRunner.class)
#PrepareForTest({ServerSocket.class})
public class abcTest {
#Mock (name = "server") //same name as private var.
ServerSocket mockServer;
#InjectMocks
Abc abc;
#Test
public void testInit() throws Exception {
int port = 1880;
Socket mockClient = Mockito.mock(Socket.class);
PowerMockito.whenNew(ServerSocket.class).
withArguments(anyInt()).thenReturn(mockServer);
abc = new Abc(port);
Abc.init();
PowerMockito.verifyNew(ServerSocket.class).withArguments(port);
}
};
But the call always go to original function definition. I am using junit 4.11 with mockito 2.28.2 and powermockito 2.0.2. I'm using java after a long time. Now its feel like kind of new. Please correct me if anything wrong in the code also.
You will need to change your PrepareForTest annotation
to #PrepareForTest({Abc.class}).
From the PowerMockito docu:
This annotation tells PowerMock to prepare certain classes for testing. Classes needed to be defined using this annotation are typically those that needs to be byte-code manipulated
In this case that refers to the class which creates the new instance of ServerSocket. ServerSocket itself is a non-final public class that does not require special handling from PowerMockito (instead Mockito can deal with this class on its own).
You could also change your test to do the following:
#Test
public void testInit() throws Exception {
int port = 1880;
ServerSocket mockServer = Mockito.mock(ServerSocket.class);
PowerMockito.whenNew(ServerSocket.class)
.withArguments(Mockito.anyInt()).thenReturn(mockServer);
Abc.port = port;
Abc.init();
PowerMockito.verifyNew(ServerSocket.class).withArguments(port);
}
(This first point is unrelated to whether the test fails or succeeds)
I do not know why you mix object's and static method behaviour together, but I think you should change that.In the test instead of creatic an ABC object, just could just set the static port variable directly.
Or alternatively change the whole ABC class into an object.
#InjectMocks failed for me as there is no default constructor
(Actually I got an error message in the console when trying to execute your code)
Additonaly you create a new instance of ABC in your test, which would have overwritten the things done by the annotations. Also as server is created during the init call, there is no need to inject a mock for it.
powermockito 2.0.2 actually depends on junit 4.12, so I am not sure what effects downgrading to an older version might have.
Socket mockClient seemed somewhat unrelated to the code your posted, so I removed it from my example in the answer, however as you use a client (I assume that is your Socket) in your code your probably need to do some mocking for that as well and provide the mock to the method accordingly.

How to make a valid test using the mockito library?

The context
I have a simple method that I'm testing using the mockito library.
The problem
I have a error:
"[MockitoHint] ReceiveServiceTest.testGetFileDto (see javadoc for MockitoHint):
[MockitoHint] 1. Unused... -> at .ReceiveServiceTest.testGetFileDto(ReceiveServiceTest.java:46)
[MockitoHint] ...args ok? -> at ReceiveService.getFileDto(ReceiveService.java:28)
I dont understand way.
The code
#RunWith(MockitoJUnitRunner.class)
public class ReceiveServiceTest {
private List<File> filePaths = new ArrayList<>();
#InjectMocks
private ReceiveService receiveService;
#Mock
private FindFiles findfiles;
#Mock
private ReadByte readByte;
#Before
public void before() {
filePaths.add(new File("d://folder//test1_message_received"));
filePaths.add(new File("d://folder//test2_message_received"));
filePaths.add(new File("d://folder//test3_message_received"));
}
#Test
public void testGetFileDto() throws IOException {
// Given
byte[] resultByteArr = new byte[1028];
when(findfiles.getPathFiles()).thenReturn(filePaths);
when(readByte.readByteArrFromFile(new File("d://folder//test3_message_received"))).thenReturn(resultByteArr);
List<MessageDTO> result = receiveService.getFileDto();
//some assert
}
method
#Autowired
private FindFiles findFiles;
#Autowired
private ReadByte readByte;
public List<MessageDTO> getFileDto() throws IOException {
List<MessageDTO> fileDtos = new ArrayList<>();
for (File file : findFiles.getPathFiles()) {
fileDtos.add(new MessageDTO(Base64.getEncoder().encode(readByte.readByteArrFromFile(new File(file.getPath()))),
file.getName(), "zip", null));
}
return fileDtos;
}
I think mocks are not being initialized. Please initialize the mocks in the #Before method.
#Before
public void init() {
initMocks(this);
}
This should solve the problem I guess.
Here is solution for my problem. I added foreach loop. Now the mock works, but byte [] is different than what it should return.
// Given
byte[] mockByteArr = new byte [2048];
when(findfiles.getPathFiles()).thenReturn(filePaths);
for (File filePath : filePaths) {
when(readByte.readByteArrFromFile(new File(filePath.getPath()))).thenReturn(mockByteArr);
}
//When
List<MessageDTO> result = receiveService.getFileDto();
//Then
assertEquals(3, result.size());
assertEquals(mockByteArr, result.get(1).getContent());
Your problem is, that you create a new object in the following line:
when(readByte.readByteArrFromFile(new File("d://folder//test3_message_received"))).thenReturn(resultByteArr);
Mockito needs to know which real object is passed to the method so that it can return the appropriate thenReturn-value. So if you pass the actual reference into it, your code will work, but also only if you specify all the values which are listed. Otherwise you may get a NullPointerException.
By the way, calling new File(file.getPath()) seems redundant to me. You can just use file instead.
So with the following your code might work better:
when(readByte.readByteArrFromFile(filePaths.get(0)).thenReturn(resultByteArray);
but then you need to specify it for all entries.
Alternatively, use a Matcher instead:
when(readByte.readByteArrFromFile(ArgumentMatchers.any(File.class))).thenReturn(resultByteArr);
or specify the actual argument matching you require as matchers can be very powerful in that regard.
Previously the answer contained the following, which is still true, but not as concise as the answer above:
It's been a long time since I last used mocks (and I am even proud of it ;-)).
The message already states that one should consult the javadoc and there I found the following:
Those are hints - they not necessarily indicate real problems 100% of the time.
Nonetheless, I believe the problem is with the following statement:
when(readByte.readByteArrFromFile(new File("d://folder//test3_message_received"))).thenReturn(resultByteArr);
I think you need to specify a return for every entry in the filePaths or make the call more generic using Matchers.any() (or any other appropriate Matcher).

Mockito/PowerMock when....then not being invoked?

When I execute the following test, the original object is being returned and not the mock, so the real method getLevelCriteriaForLevel(level) is being executed (I observed that with the debugger). Why is that so? I'm pretty sure that this already worked yesterday and I didn't change anything there.
I already tried
#PrepareForTest({LevelCriteria.class, LevelGenerator.class})
or used the MockitoJunitRunner as I did before, but this doesn't help either.
Here is the code (generateConcreteLevel is a private method. The expected exception is only thrown when I pass this data from the mock. Otherwise it's not thrown. The test fails because the exception is not thrown, because the test doesn't use the mock object but the real object):
public class LevelGenerator
{
public void createLevel(int level)
{
generateConcreteLevel(levelCriteria.getLevelCriteriaForLevel(level));
}
private void generateConcreteLevel(LevelCriterion levelCriterion)
{
int entryGroupCount = levelCriterion.getEntryGroupCount();
int exitGroupCount = levelCriterion.getExitGroupCount();
int exitsWhileEntries = levelCriterion.getExitsWhileEntries();
int maxGroupSize = levelCriterion.getMaxGroupSize();
List<Question> questions = levelCriterion.getQuestions();
int speed = levelCriterion.getSpeed();
Range blueItemsCount = levelCriterion.getBlueItemsCount();
Range brownItemsCount = levelCriterion.getBrownItemsCount();
Range greenItemsCount = levelCriterion.getGreenItemsCount();
Range redItemsCount = levelCriterion.getRedItemsCount();
Range whiteItemsCount = levelCriterion.getWhiteItemsCount();
Range timespanBetweenGroups = levelCriterion.getTimespanBetweenGroups();
float fractionOfCarAmountToLeave = levelCriterion.getFractionOfCarAmountToLeave();
float fractionOfMinimumItemsAmountInCarParkToStartExits = levelCriterion.getFractionOfMinimumItemsAmountInCarParkToStartExits();
checkItemsFitInEntryGroups(entryGroupCount, maxGroupSize, blueItemsCount, brownItemsCount, greenItemsCount, redItemsCount, whiteItemsCount);
}
private void checkItemsFitInEntryGroups(int entryGroupCount, int maxGroupSize, Range... ranges)
{
int totalRangeCount = 0;
for (Range range : ranges)
{
totalRangeCount += range.getMaximum();
}
if (totalRangeCount > entryGroupCount * maxGroupSize)
{
throw new UnsupportedOperationException("Error in level criterion: Not enough entry groups for Items.");
}
}
}
and the test...
#RunWith(PowerMockRunner.class)
public class LevelGeneratorTest
{
#Mock
private LevelCriteria levelCriteriaMock;
#InjectMocks
private LevelGenerator levelGenerator;
#Test(expected=UnsupportedOperationException.class)
public void tooLessPositionsInEntryGroups()
{
LevelCriterion levelCriterion = new LevelCriterion.LevelCriterionBuilder()
.withBlueItemsCount(new Range(10, 10))
.withEntryGroupCount(3)
.withExitGroupCount(3)
.withMaxGroupSize(3)
.build();
when(levelCriteriaMock.getLevelCriteriaForLevel(anyInt())).thenReturn(levelCriterion);
levelGenerator.createLevel(0);
}
}
By the way: It's not an Eclipse problem, since a Maven build produces the same error.
I know that I can execute the private method with PowerMockito's Whitebox directly what I will do after refactoring, but the question is, why when...then is not working here.
Assuming your question is:
Why is the real method getLevelCriteriaForLevel(level) executed when I expect to have the mocked implementation?
I will try to demonstrate that everything works as expected fine if you reproduce it is a simple example (switch from your current workspace if you need to).
I do not have you LevelCriterion.LevelCriterionBuilder() so I simplified your test by just instantiating a LevelCriterion (empty object). This is not relevant because in my implementation I will always return an UnsupportedOperationException.
Here is how my LevelGenerator looks like. The UnsupportedOperationException is as simple as possible LevelGenerator#generateConcreteLevel(LevelCriterion).
If implemented like this:
public class LevelGenerator
{
LevelCriteria levelCriteria;
public void createLevel(int level)
{
generateConcreteLevel(levelCriteria.getLevelCriteriaForLevel(level));
}
private void generateConcreteLevel(LevelCriterion levelCriteriaForLevel)
{
throw new UnsupportedOperationException("xxx");
}
}
The test is green, using a #RunWith(MockitoJUnitRunner.class) on top of LevelGeneratorTest.
I did not used #PrepareForTest or PowerMockRunner. I have Mockito version 1.9.5.
I am sure that I have not used the real getLevelCriteriaForLevel(level) implementation, because it looks like this:
public class LevelCriteria {
public LevelCriterion getLevelCriteriaForLevel(int level) {
throw new IllegalStateException("Unexpected call");
}
}
If the real getLevelCriteriaForLevel(int) is excuted the test is red (because an IllegalStateException is thrown).
And the test is still green...
This works with pure-Mockito (version 1.9.5) approach.
You should remove all other mocking library (PowerMock, EasyMock...)
Are you sure that your static call of when(..).thenReturn(..) is the Mockito one?
Have you tried: Mockito.when(..).thenReturn(..)
I hope it helps.
PS: I have seen that you updated the question. It is a little bit unfair for me, but I am not going to update my answer once again.
I do not need the implementation detail of generateConcreteLevel(..) to illustrate that the when(..) call is working. Read my answer again. Try it in a separate workspace and you will see by yourself.
PS-2: I am using Eclipse too... Why should it be a problem? Eclipse is a great IDE.
I figured out what's wrong. Unfortunately you don't see the real problem in this question since I simplified the classes:
My real implementation of LevelGenerator got a parameterized constructor today. That's the reason why it worked yesterday but not anymore. Obviously there are mock injection problems with Mockito when not using a standard constructor.
Result: The when...then works as excpected.

How to force a SQLException in JUnit

I'm writing unit tests in JUnit, but have not been able to successfully cover a branch of a particular method that catches a SQLException and returns a null object.
This is the class I'm testing:
#Component
public class UnitOfMeasureRowMapper implements RowMapper<UnitOfMeasure> {
public UnitOfMeasure mapRow(final ResultSet resultSet, final int rowNumber) throws SQLException {
UnitOfMeasure unitOfMeasure = new UnitOfMeasure();
try {
unitOfMeasure.setUnitOfMeasureId(resultSet.getInt("UNITOFMEASUREID"));
unitOfMeasure.setOwnerUserId(resultSet.getInt("USERID"));
unitOfMeasure.setName(resultSet.getString("NAME"));
unitOfMeasure.setDescription(resultSet.getString("DESCRIPTION"));
} catch (SQLException e) {
unitOfMeasure = null;
}
return unitOfMeasure;
}
}
This is the JUnit test that I have written to cover the second branch of the above method (with appropriate context from the test class):
private static UnitOfMeasure testUnitOfMeasure;
private static UnitOfMeasureRowMapper mockRowMapper;
public void setUp() throws Exception {
mockRowMapper = mock(UnitOfMeasureRowMapper.class);
mockResultSet = mock(ResultSet.class);
}
#Test(expected=SQLException.class)
public void testUnitOfMeasureRowMapperFailsSQLException() throws SQLException {
when(mockRowMapper.mapRow(mockResultSet, 1)).thenReturn(null);
testUnitOfMeasure = mockRowMapper.mapRow(mockResultSet, 1);
}
I think the problem is with the last line; somehow I need to force a SQLException. The problem is, I don't know how and haven't been able to find an answer. Can anyone help?
If I understand the question well, the class under test is UnitOfMeasureRowMapper. If this is true, then you don't want to mock it in your test, otherwise you are testing a mock!
What is under test in your JUnit, is the behavior of UnitOfMeasureRowMapper#mapRow when ResultSet you give it throws a SQLException during the execution of the method. Then you want this method to return null.
I would write it like this:
private ResultSet mockResultSet;
private RowMapper<UnitOfMeasure> rowMapper = new UnitOfMeasureRowMapper();
public void setUp() throws Exception {
mockResultSet = mock(ResultSet.class);
}
#Test
public void mapRow_SHOULD_return_null_WHEN_resultSet_throws_a_SQLException() {
when(mockResultSet.getInt(anyString()).thenThrow(new SQLException());
assertThat(mockRowMapper.mapRow(mockResultSet, 1), nullValue());
}
As suggested Samuel in his answer, you may set one of the method of the result set you use to throw a SQLException, and then check in your JUnit that the mapRow method returns null as expected. Here you are not testing the behavior of the result set, so its fine to mock it to achieve a behavior it would normally have under some circunstancies that would be painful to obtain otherwise. Mocking the result set behavior lets you focus on testing the RowMapper behavior.
You are testing the UnitOfMeasureRowMapper that implements RowMapper. So have a rowMapper property in your JUnit, and I prefer to see it through its interface. I like to brutally call the constructor of UnitOfMeasureRowMapper because I want to keep my JUnit as simple as they can be.
Set one of the methods (maybe getInt?) of your mock ResultSet to throw the exception. You didn't specify what mocking framework you're using so I can't tell you the exact syntax.