This may be a stupid question, as I'm just starting out with jUnit testing, but I need to test that an object of a class is NOT created in the main() method.
Basically, what I need is the opposite of this code I guess:
PowerMockito.whenNew(Test.class).withNoArguments().thenReturn(PowerMockito.mock(Test.class));
Test.main(null);
PowerMockito.verifyNew(Test.class).withNoArguments();
The test code above checks that there's a Test object created within the main() method. What I need is a test that scans main() and makes sure that the Test test = new Test() is NOT created there.
Found the solution, in case anyone runs into the same issue.
Basically, just need to add an extra argument call to never() method within verifyNew(), like so:
PowerMockito.verifyNew(Test.class, never()).withNoArguments();
Related
I'm new to Junit. I want to write test cases for if condition,loops.
Do we have any guidelines or procedure to write test cases for if,loop conditions?
Can anyone explain with an example?
IF Age < 18 THEN WHILE Age <> 18
DO ResultResult = Result +1 AgeAge = Age +1 END
DO Print “You can start driving in {Result} years”
ELSE
Print “You can start driving now!”
ENDIF
You want one test case for each major scenario that your code is supposed to be able to handle. With an "if" statement, there are generally two cases, although you might include a third case which is the "boundary" of the two. With a loop, you might want to include a case where the loop is run multiple times, and also a case where the loop is not run at all.
In your particular example, I would write three test cases - one where the age is less than 18, one where the age is exactly 18, and one where the age is over 18. In JUnit, each test case is a separate method inside a test class. Each test method should run the code that you're testing, in the particular scenario, then assert that the result was correct.
Lastly, you need to consider what to call each test method. I strongly recommend using a sentence that indicates which scenario you're testing, and what you expect to happen. Some people like to begin their test method names with the word "test"; but my experience is that this tends to draw attention away from what CONDITION you're trying to test, and draws attention toward which particular method or function it is that you're testing, and you tend to get lower quality tests as a result. For your example, I would call the test methods something like this.
public void canStartDrivingIfAgeOver18()
public void canStartDrivingIfAgeEquals18()
public void numberOfYearsRemainingIsShownIfAgeUnder18()
From my understanding of writing in junit for java ,we were used to create a source code into different blocks is the code conventional,and used to pass the values as args to the function from the test cases so the values will steps into the block statements ,and passes the test cases .
For example you are having the variable as age by assuming as functionName(int age), for testing you should pass the integer from the test case as functionName(18) it will steps into the statements and will show you the status of the test case.Create test case for a testing class write test case for the functions
UseClass classObj=new UseClass();// it should be your class
#Test
public void testValidateAge() {
classObj.validateAge("20");
assertEquals(200,"");
}
Correct me if 'm wrong :)
Let say I have a test class called MyTest.
In it I have three tests.
public class MyTest {
AnObject object;
#Before
public void setup(){
object = new AnObject();
object.setSomeValue(aValue);
}
#Test
public void testMyFirstMethod(){
object.setAnotherValue(anotherValue);
// do some assertion to test that the functionality works
assertSomething(sometest);
}
#Test
public void testMySecondMethod(){
AValue val = object.getAnotherValue();
object.doSomethingElse(val);
// do some assertion to test that the functionality works
assertSomething(sometest);
}
Is there any way I can use the value of anotherValue, which is set with its setter in the first test, in the second test. I am using this for testing database functionality. When I create an object in the DB I want to get its GUID so I can use this to do updates and deletes in later test methods, without having to hardcode the GUID and therefore making it irrelevant for future use.
You are introducing a dependency between two tests. JUnit deliberately does not support dependency between tests, and you can't guarantee the order of execution (except for test classes in a test suite, see my answer to Has JUnit4 begun supporting ordering of test? Is it intentional?). So you really want to have dependencies between two test methods:
you have to use an intermediate static value
as Cedric suggests, use TestNG, which specifically supports dependencies
in this case, you can create a method to create the line, and call it from both methods.
I would personally prefer 3, because:
I get independent tests, and I can run just the second test (in Eclipse or such like)
In my teardown in the class, I can remove the line from the database, the cleanup. This means that whichever test I run, I always start off with the same (known) database state.
However, if your setup is really expensive, you can consider this to be an integration test and just accept the dependency, to save time.
You should use TestNG if you need this (and I agree it's fairly common in integration testing). TestNG uses the same instance to run your tests, so values stored in fields are preserved between tests, which is very useful when your objects are expensive to create (JUnit forces you to use statics to achieve the same effect, which should be avoided).
First off, make sure your #Test 's run in some kind of defined order
i.e. #FixMethodOrder(MethodSorters.NAME_ASCENDING)
In the example below, I'm assuming that test2 will run after test1
To share a variable between them, use a ThreadLocal (from java.lang).
Note that the scope of the ThreadLocal variable is to the thread, so if you are running multiple threads, each will have a copy of 'email' (the static in this case implies that its only global to the thread)
private static ThreadLocal<String> email = new ThreadLocal<String>();
#Test
public void test1 {
email.set("hchan#apache.org);
}
#Test
public void test2 {
System.out.println(email.get());
}
You should not do that. Tests are supposed to be able to run in random order. If you want to test things that depend on one value in the database, you can do that in the #Before code, so it's not all repeated for each test case.
I have found nice solution, just add Before annotation to the previous test!
private static String email = null;
#Before
#Test
public void test1 {
email = "test#google.com"
}
#Test
public void test2 {
System.out.println(email);
}
If you, like me, googled until here and the answer didn't serve to you, I'll just leave this: Use #BeforeEach
I am using Moq, NUnit, WPF, MVVM, Ninject.
I am writing a test for my LoginViewModel, and in the test when I use the constructor of the LoginViewModel to create a new instance, I am getting a NullReferenceException error. The code compiles and runs, (i.e. when I run the program the LoginView shows, and works with the LoginViewModel to create the correct behaviour etc) but for some reason the UnitTest is crashing.
this is the constructor:
public LoginViewModel(ILoginServices loginServices,IDialogService dialogServices)
{
InitializeFields();
_loginServices = loginServices;
_dialogService = dialogServices;
DomainList = _loginServices.GetDomainListing();
}
I have mocked the dependencies as follows:
Mock<ILoginServices> moq = new Mock<ILoginServices>();
moq.Setup(log =>
log.LoginUser(It.IsAny<string>(),
It.IsAny<string>(),
It.IsAny<string>()))
.Callback<string, string, string>((i, j, k) => CheckArgs(i, j, k));
moq.Setup(log2 =>
log2.GetDomainListing()).Returns(new List<string> { "Domain" });
Mock<IDialogService> moq2 = new Mock<IDialogService>();
I have also tried inserting real services as the parameters.
I have verified that the mocks do work, and the objects these mocks
return are not null.
I have commented out all the code in the constructor.
I have tried inserting the line
LoginViewModel test = new LoginViewModel(_fakeLoginService,_fakeDialogService);
in front of the call to the constructor (to see if it had to do with the original local variable being disposed or something before) and this line crashed instead.
From all I can see this must be the constructor,(but not the code I have written inside it) and that this is solely related to NUnit / Moq as my code still compiles and runs fine.
I have no idea on this one guys, can anyone point me in the right direction?
[Edit]
Ok so I have run through the code and the error comes from this line of code:
ImageSource = (ImageSource)Application.Current.FindResource(_imageName);
This code is going to a ImageDictionary and getting a reference to the image for an undo button in the WindowViewModel (which my LoginViewModel inherits).
My hypotheses as to why its working in the normal running of the application, but not in the testing are:
1) Because I am running the program code through NUnit, the Application.Current object isnt getting property assigned/there is no Application.Current object to get.
**or**
2) Something to do with the fact that because the program code is being run in NUnit, the code doesn't have access to/can't resolve the ImageDictionary to find the image.
I'm leaning more strongly to the first hypothesis, but I'm as of yet not 100% sure, and I am having trouble finding the values of the Application.Current at runtime, cause when I move my cursor over the code the tooltip that normally appears showing the detail of the object that is not appearing.
My new question is: Does any of this make sense? Do you guys know if the Application.Current object exists / can be accessed when running the testing project through NUnit?
Any help will be appreciated.
You are correct. Application.Current is null for Unit tests. You can work around this by injecting the Application object as referencing singletons in code can make life tricky.
I have a Junit test class with two tests in it. test 1 will add an element to an ArrayList and passes it to the main class to do some logic and returns true. Test two should use the same arrayList and calls the same main class do the same logic but by the time the list comes to second test methods, its getting null.
I declared it as class variable. My questions is.. when I assign values to a class variable in a test method, will I not have access to the values in next test method? If yes, how should i retain the values.
Thanks,
Mahi
The way variables work in jUnit is that they get initialized before each test. So if you added value x to a list in Test1, it won't be there when you run Test2. If you want to some kind of initialization before each test, use the setup method.
I'm trying to setup a test in JUnit w/ EasyMock and I'm running into a small issue that I can't seem to wrap my head around. I was hoping someone here could help.
Here is a simplified version of the method I'm trying to test:
public void myMethod() {
//(...)
Obj myObj = this.service.getObj(param);
if (myObj.getExtId() != null) {
OtherObj otherObj = new OtherObj();
otherObj.setId(myObj.getExtId());
this.dao.insert(otherObj);
}
//(...)
}
Ok so using EasyMock I've mocked the service.getObj(myObj) call and that works fine.
My problem comes when JUnit hits the dao.insert(otherObj) call. EasyMock throws a *Unexpected Method Call* on it.
I wouldn't mind mocking that dao in my test and using expectLastCall().once(); on it, but that assumes that I have a handle on the "otherObj" that's passed as a parameter at insert time...
Which of course I don't since it's conditionally created within the context of the method being tested.
Anyone has ever had to deal with that and somehow solved it?
Thanks.
You could also use EasyMock.isA(OtherObj.class) for a little more type safety.
If you can't get a reference to the object itself in your test code, you could use EasyMock.anyObject() as the expected argument to yourinsert method. As the name suggests, it will expect the method to be called with.. well, any object :)
It's maybe a little less rigorous than matching the exact argument, but if you're happy with it, give it a spin. Remember to include the cast to OtherObjwhen declaring the expected method call.
The anyObject() matcher works great if you just want to get past this call, but if you actually want to validate the constructed object is what you thought it was going to be, you can use a Capture. It would look something like:
Capture<OtherObj> capturedOtherObj = new Capture<OtherObj>();
mockDao.insert(capture(capturedOtherObj));
replay(mockDao);
objUnderTest.myMethod();
assertThat("captured what you expected", capturedOtherObj.getValue().getId(),
equalTo(expectedId));
Also, PowerMock has the ability to expect an object to be constructed, so you could look into that if you wanted.
Note also that if you use EasyMock.createStrictMock();, the order of the method calls is also important and if you break this rule, it would throw an unexpected method call.