JUnit expected exception not working as expected - java

i am trying to test a private method inside an ActionListener. The method should throw an exception if an invalid url is passed:
Heres the code of my test:
#Rule
public ExpectedException expectedException = ExpectedException.none();
Map<JLabel, JTextField> inputs;
ActionListener listener;
AddStationWindow window;
ArrayList<Station> stationsToDelete;
#Before
public void setUp() throws IllegalAccessException, NoSuchFieldException,
InstantiationException, SQLException, ClassNotFoundException {
inputs = new HashMap<JLabel, JTextField>();
window = new AddStationWindow();
stationsToDelete = new ArrayList<>();
InitializeH2Database.initialiteDatabase();
}
#Test
public void saveStation() throws NoSuchFieldException,
IllegalAccessException, MalformedURLException, NoSuchMethodException,
InvocationTargetException {
Field f = window.getClass().getDeclaredField("inputElements");
f.setAccessible(true);
LinkedHashMap<JLabel, JTextField> inputs = (LinkedHashMap<JLabel,
JTextField>) f.get(window);
Field f2 = window.getClass().getDeclaredField("save");
f2.setAccessible(true);
JButton saveButton = (JButton) f2.get(window);
inputs.get(window.getInputLabels().get(0)).setText("Testsender");
inputs.get((window.getInputLabels().get(1))).setText("asdasdsa");
ActionListener listener = saveButton.getActionListeners()[0];
Method m = listener.getClass().getDeclaredMethod("saveStation");
m.setAccessible(true);
m.invoke(listener);
expectedException.expect(MalformedURLException.class);
}
#After
public void tearDown() {
stationsToDelete.forEach(s ->
H2DatabaseConnector.getInstance().deleteStation(s));
}
This is the tested method inside the ActionListener:
private boolean saveStation() {
List<JLabel> keys = new ArrayList<>();
for (Map.Entry<JLabel, JTextField> inputElement : inputElements.entrySet()) {
keys.add(inputElement.getKey());
}
String stationName = inputElements.get(keys.get(0)).getText();
String urlString = inputElements.get(keys.get(1)).getText();
URL stationURL = null;
try {
stationURL = new URL(urlString);
} catch (MalformedURLException e) {
JOptionPane.showMessageDialog(window, "Invalid URL!", "URL
not valid", JOptionPane.ERROR_MESSAGE);
e.printStackTrace();
return false;
}
Station s = new Station(stationName, stationURL);
if (checkStation(s)) {
return WebradioPlayer.addStation(s);
}
return false;
}
If i run the test, i can see that the stack tarce shows the malformed url exception with message no protocol: 'asdasdsa', but the test fails.
Can someone explain me why? JUnit version is 4.

You have to set the expected exception before you call the code that actually does throw the exception.
Instead of
#Test
public void saveStation() throws ... {
// code here
expectedException.expect(MalformedURLException.class);
}
you should write the test method as
#Test
public void saveStation() throws ... {
expectedException.expect(MalformedURLException.class);
// code here
}
Additionally, you have to change your method saveStation to not suppress the exception if you actually want to have it thrown. See #Leviand's answer for more details.

Your test is failing because you are expecting an exception to be thrown (you said invalid url exception), but you are wrapping that exception into a try catch, then you are printing the stacktrace.
try {
stationURL = new URL(urlString);
} catch (MalformedURLException e) {
JOptionPane.showMessageDialog(window, "Invalid URL!", "URL
not valid", JOptionPane.ERROR_MESSAGE);
e.printStackTrace();
return false;
}
you have to add the trown declaration in your catch, or not catch it at all, ie:
} catch (MalformedURLException e) {
JOptionPane.showMessageDialog(window, "Invalid URL!", "URL
not valid", JOptionPane.ERROR_MESSAGE);
e.printStackTrace();
throw new MalformedURLException(e);
}
and add the throw info to your method
private boolean saveStation() throws MalformedURLException{

Related

How to mock IOException for CharSource.read()?

here is the code for which I want to write a test case for catch block
public class X {
protected String getInputString(final String inputPath) {
try {
return Resources.asCharSource(Resources.getResource(inputPath), UTF_8).read();
} catch (final IOException e) {
log.error("Error loading partner aliases from local config", e);
throw new UncheckedIOException(e);
}
}
}
have tried mocking the staic method asCharSource as bellow:
#Test
public void Failed() throws Exception{
URL url = Resources.getResource("resources/linearPartners.json");
CharSource s;
try{
s = new CharSource() {
#Override
public Reader openStream() throws IOException {
throw new IOException("Expected as a test");
}
#Override
public String read() throws IOException {
throw new IOException("Expected as a test");
}
};
try (MockedStatic<Resources> resources = Mockito.mockStatic(Resources.class)) {
resources.when(() -> Resources.asCharSource(url, UTF_8))
.thenReturn(s);
Assertions.assertThrows(UncheckedIOException.class, () -> staticConfigPartnerAliasesPersistenceFacade.getInputString("resources/file.json"));
}
} catch (Exception e) {
e.printStackTrace();
}
}
bellow is the error
org.opentest4j.AssertionFailedError: Unexpected exception type thrown ==> expected: <java.io.UncheckedIOException> but was: <java.lang.NullPointerException>
[java] org.junit.jupiter.api.AssertThrows.assertThrows(AssertThrows.java:65)
[java] org.junit.jupiter.api.AssertThrows.assertThrows(AssertThrows.java:37)
[java] org.junit.jupiter.api.Assertions.assertThrows(Assertions.java:3082)
I did not understand, where is the NullPointerException is coming from. Please guide me on this

Using reflection to identify if the error thrown matches expected error

I need to write a simple code tester program, but I got stuck comparing the given error class with the test expected class. I am supposed to use reflection in this exercise.
I have my code testing class:
public class TestRunner {
private String result = "";
public void runTests(List<String> testClassNames) {
for (String testClassName : testClassNames) {
Class<?> clazz;
try {
clazz = Class.forName(testClassName);
} catch (ClassNotFoundException e) {
throw new IllegalStateException("No such class.");
}
Method[] methods = clazz.getMethods();
for (Method method : methods) {
if (method.getAnnotation(MyTest.class) != null) {
if (testClassName.equals("reflection.tester.ExampleTests1")) {
result += method.getName() + "() - ";
ExampleTests1 instance = new ExampleTests1();
try {
// if null, result = OK
method.invoke(instance);
result += "OK\n";
} catch (IllegalArgumentException | IllegalAccessException | InvocationTargetException e) {
// if error is caught result = FAILED
result += "FAILED\n";
}
} else {
// the second class. should only return "OK" if the error is implemented from the exception class
result += method.getName() + "() - ";
ExampleTests2 instance = new ExampleTests2();
try {
method.invoke(instance);
result += "FAILED\n";
} catch (RuntimeException e) {
Throwable original = e.getCause();
Object expected = method.getReturnType();
if (original.getClass().isAssignableFrom(expected.getClass())) {
result += "OK\n";
} else {
result += "FAILED\n";
}
} catch (InvocationTargetException | IllegalAccessException e) {
result += "ERROR\n";
}
}
}
}
}
}
}
Also have two test classes. In the first one there is only one rule, if the test won't throw an exception the test should pass, and it is working. The second class is more complicated. If the thrown error class is implemented or same to the expected error class then the test should pass and OK should be added to the result. Currently my code won't catch RunTimeException at all and moves to the last catch block. How can I fix this?
I will also add the test class for more information.
public class ExampleTests2 {
#MyTest(expected = RuntimeException.class)
public void test3() {
throw new IllegalStateException();
}
#MyTest(expected = IllegalStateException.class)
public void test4() {
throw new RuntimeException();
}
#MyTest(expected = IllegalStateException.class)
public void test5() {
throw new IllegalStateException();
}
#MyTest(expected = IllegalStateException.class)
public void test6() {
}
public void helperMethod() {
}
}
test3() and test5() should pass, test4() and test6() should fail, helperMethod() won't be checked because I only need to use the tests with #MyTest annotation.
JUnit has an assertThrows method that checks that an Exception is thrown. It has a method signature of
static <T extends Throwable> assertThrows​(Class<T> expectedType, Executable executable){}
Here's the documentation: https://junit.org/junit5/docs/current/api/org.junit.jupiter.api/org/junit/jupiter/api/Assertions.html#assertThrows(java.lang.Class,org.junit.jupiter.api.function.Executable)
and here's how JUnit implements it:
https://github.com/junit-team/junit5/blob/main/junit-jupiter-api/src/main/java/org/junit/jupiter/api/AssertThrows.java

JUnit test not catching exception

UPDATE: Here's the full test:
#Test(expected = NullPointerException.class)
public void testMissingData() throws Exception{
Resource<ObjectDataModel, Content, Status> resource = builder.build(content, argA1Response,
argA2Response, objFilterParam, argA3Response);}
And here's the build method:
public Resource<ObjectDataModel, Content, Status> build(Content argContent,
ResponseA1 argA1Response,
ResponseA2 argA2Response, String argObjectTypeFilter,
ResponseA3 argA3Response) {
try {
viewDataModel.setObjectType(this.buildObjectType(filteredObjectType,
argA1Response.getData().getDataObject().getCategories().get(0).getObjectTypes().get(0)));
}
catch (Exception e) {
String msg = "Exception occoured while buildng the Object Data Model";
LOG.error(msg, e);
}
// we have the required information gathered to return
return Resource.okFromDataAndContent(viewDataModel, argContent);
}
And here's the buildObjectType() method:
private ObjectType buildObjectType(ObjectTypes argA1ProductType,
PendingObjectTypes argA2ProductType) {
ProductType objectType = new ObjectType();
List<Plan> plans = argA1ObjectType.getPlan();
List<PendingObjectSummary> objPlans = argA1ObjectType.getData();
if (objectType.getData() == null) {
objectType.setData(new ArrayList<>());
}
PendingObjectSummary tempPlan = null;
for (Plan currPlan : plans) {
tempPlan = plans.stream()
.filter(plan -> plan.getObjId().equals(currPlan.getObjId()))
.findFirst()
.orElseThrow(NullPointerException::new);
}
return objectType;
}
I'm using an Optional to test for null and I can confirm that the exception is being thrown -- but JUnit isn't catching it. Here's the test case:
#Test(expected = NullPointerException.class)
public void testMissingData() throws Exception{
Object<> response = fixture.create();
assertNotNull(response);
assertNotNull(response.getData());
assertNull(resource.getData().getObjectType());
}
In my create method I'm simply iterating over a bunch of objects to try and find one that matches my ID; if not found then throw a NullPointerException:
for (Object currObj : objects) {
tempObj = myOtherCollection.stream()
.filter(obj -> obj.getId().equals(currObj.getId()))
.findFirst()
.orElseThrow(NullPointerException::new);
}
The JUnit output clearly isn't catching the exception - here's the output:
java.lang.AssertionError: Expected exception: java.lang.NullPointerException
And my tomcat logs are definitely throwing the exception here:
18:48:30.015 [main] ERROR com.myCompany.src.ModelBuilder - Exception occoured while buildng the Data Model
java.lang.NullPointerException: null
at java.util.Optional.orElseThrow(Optional.java:290)
The only issue I can see is that maybe where I assign tempObj that the code is wrong. Am I missing anything obvious? Thanks for any helpful tips.
You are catching the nullpointer exception so the exception is not propagated to your test.
see
try {
viewDataModel.setObjectType(this.buildObjectType(filteredObjectType,
argA1Response.getData().getDataObject().getCategories().get(0).getObjectTypes().get(0)));
}
catch (Exception e) {
String msg = "Exception occoured while buildng the Object Data Model";
LOG.error(msg, e);
}
If you want to test for an exception you could throw an exception in your error handling (for example a custom ObjectCreationExcepion) and assert that that one is thrown, like
try {
viewDataModel.setObjectType(this.buildObjectType(filteredObjectType,
argA1Response.getData().getDataObject().getCategories().get(0).getObjectTypes().get(0)));
}
catch (Exception e) {
String msg = "Exception occoured while buildng the Object Data Model";
LOG.error(msg, e);
throw new ObjectCreationException(msg);
}
and in your test
#Test(expected = ObjectCreationException.class)
public void testMissingData() throws Exception{
Object<> response = fixture.create();
}
#Test(expected = ObjectCreationException.class) only handles exceptions that are not handled within the tested code OR the test itself.
So what you could do is
public Resource<ObjectDataModel, Content, Status> build(Content argContent,
ResponseA1 argA1Response,
ResponseA2 argA2Response, String argObjectTypeFilter,
ResponseA3 argA3Response) throws NullPointerExceptions // << notice thrwoing declatration
{ // do some stuf}
and then in test you can handle it like you where trying by
public void testMissingData() throws Exception{
Resource<ObjectDataModel, Content, Status> resource = builder.build(content, argA1Response,
argA2Response, objFilterParam, argA3Response);
}

Unhandled exceptions thrown by a method does not prevent compilation

So I have these two methods in a class:
public String getConsumerKey() throws FileNotFoundException, IOException
{
String consumerKey;
consumerKey = getPropertyValueOrNull(getConfigPath(CONSUMERVALUESCONFIGNAME),"consumer_key");
return consumerKey;
}
private String getPropertyValueOrNull(String path, String key) throws FileNotFoundException, IOException
{
Properties prop = new Properties();
String value = null;
// load a properties file
prop.load(new FileInputStream(path));
value = prop.getProperty(key);
if ( value == null || value.isEmpty())
{
value = null;
}
return value;
}
And I call getCosumerKey() from the main method like this:
public static void main(String[] args)
{
try {
MyClass.getInstance().getConsumerKey();
} catch (IOException e) {
e.printStackTrace();
}
}
When I run this code, there is no problem except that I am getting a FileNotFoundExcpetion. When I tried to add a catch block to handle the FileNotFoundException, I got an error saying that the exception is already handled from the IOException catch block.
Isn't the compiler supposed to prevent me from running the code and why does not compiler let me handle the exception?

Why is the main method not covered?

main method:
public static void main(String[] args) throws Exception
{
if (args.length != EXPECTED_NUMBER_OF_ARGUMENTS)
{
System.err.println("Usage - java XFRCompiler ConfigXML PackageXML XFR");
}
String configXML = args[0];
String packageXML = args[1];
String xfr = args[2];
AutoConfigCompiler compiler = new AutoConfigCompiler();
compiler.setConfigDocument(loadDocument(configXML));
compiler.setPackageInfoDoc(loadDocument(packageXML));
// compiler.setVisiblityDoc(loadDocument("VisibilityFilter.xml"));
compiler.compileModel(xfr);
}
private static Document loadDocument(String fileName) throws Exception
{
TXDOMParser parser = (TXDOMParser) ParserFactory.makeParser(TXDOMParser.class.getName());
InputSource source = new InputSource(new FileInputStream(fileName));
parser.parse(source);
return parser.getDocument();
}
testcase:
#Test
public void testCompileModel() throws Exception
{
// construct parameters
URL configFile = Thread.currentThread().getContextClassLoader().getResource("Ford_2008_Mustang_Config.xml");
URL packageFile = Thread.currentThread().getContextClassLoader().getResource("Ford_2008_Mustang_Package.xml");
File tmpFile = new File("Ford_2008_Mustang_tmp.xfr");
if(!tmpFile.exists()) {
tmpFile.createNewFile();
}
String[] args = new String[]{configFile.getPath(),packageFile.getPath(),tmpFile.getPath()};
try {
// test main method
XFRCompiler.main(args);
} catch (Exception e) {
assertTrue(true);
}
try {
// test args length is less than 3
XFRCompiler.main(new String[]{"",""});
} catch (Exception e) {
//ignore
}
tmpFile.delete();
}
Coverage outputs displayed as the lines from String configXML = args[0]; in main method
are not covered.
assertTrue(true); is a pointless no-op
Remove the try/catch around the call to XFRCompiler.main(args);, since all it does is swallow excpetions and make debugging harder; most likely you will then see an exception that tells you where the problem is.
There should be a call to fail() after the call to XFRCompiler.main(new String[]{"",""}); since you expect it to throw an exception
Put the two calls in separate test methods.
I'm worried about all those assertTrue(true). If there can't be an exception, then the assert is not necessary. If there is an unexpected exception, then this code will swallow it and you will get the behavior you see right now.
Then, if you expect an exception, you should code like this:
try {
... code that will throw an exception ...
fail("No exception was thrown");
} catch (SpecficTypeOfException e) {
assertEquals("message", e.getMessage());
}
That way, wrong types of exception and the exception message will be checked.
PS: Don't post questions with "urgent". We already help as fast as we can.

Categories