There's been similar questions, but none of those can solve my current problem
Say I have a fairly simple class:
public class ClassA {
private final Object someVariable;
public classA(Object obj) {
this.someVariable = obj
}
public void Object someMethod(Object obj) throws SomeException {
//does stuff
}
}
Now, I create an instance of this class in a diff class
public class ClassB {
private final Object anotherVariable;
public void Object anotherMethod() throws SomeException {
try {
ClassA objectA = new ClassA(anotherVariable)
objectA.someMethod()
} catch {
// does stuff
}
}
}
The end goal is to test the catch block by throwing an exceptions as so
@Mock
ClassA myObject = new ClassA(obj)
...
@Test(expected = SomeException.class)
public void myTest()throws Exception {
doThrow(new SomeException()).when(myObject).someMethod(any());
}
For some reason the exceptions is just never thrown. I've also tried replacing the any()
with both valid and invalid objects, and it still doesn't work.
Edit1:
Whilst fishing for a solution, this for some reason passes the test:
@Test(expected = SomeException.class)
public voif Test() throws Exception {
doThrow(new someException()).when(myObject).someMethod(any());
when(myObject.someMethod(any())).thenThrow(new someException());
}
Any explanation as to why this works? Is this bad practice or something?
I believe the reason is that you never call the method:
@Test(expected = SomeException.class)
public void myTest(0 throws Exception {
// here you stub the method
doThrow(new SomeException()).when(myObject).someMethod(any());
// also it should probably be like this:
// doThrow(new SomeException()).when(myObject).someMethod();
// because the method in ClassA does not have any params
// you need it to be called somewhere
// you can do that explicitly
myObject.someMethod(/*perhaps some param here*/);
// or you can call some other method which calls this one
// on the mock - then you should get an exception as well
}
Also, there is a little issue in ClassB:
public void Object anotherMethod() throws SomeException {
try {
// you instantiate obj of type ClassA here
// which means you cannot mock it if you need
// to test anotherMethod()
ClassA objectA = new ClassA(anotherVariable)
objectA.someMethod()
} catch {
// does stuff
}
}
If you'd like to test ClassB.anotherMethod()
you need to get rid of this super tight coupling:
ClassA objectA = new ClassA(anotherVariable)
Consider approach like this:
public class ClassB {
private final ClassA objectA;
public ClassB(ClassA obj) {
// now you can provide any instance of ClassA instead
// of having it created in try-block later
// so when you need ClassB in real code, you can create
// some real instance of ClassA and pass to this conctructor
// and for test you can pass mock
this.objectA = obj;
}
public void Object anotherMethod() throws SomeException {
try {
objectA.someMethod()
} catch {
// does stuff
}
}
}
What this gives us:
@Mock
ClassA myObject = new ClassA(obj)
...
@Test(expected = SomeException.class)
public void myTest()throws Exception {
// stub someMethod on object of ClassA
doThrow(new SomeException()).when(myObject).someMethod();
ClassB objB = new ClassB(myObject);
// now you can test it, and inside anotherMethod()
// there will be a call to someMethod() on a mock
// so you will get an exception
objB.anotherMethod();
}
I assume since u are mocking Class A below line
@Mock
ClassA myObject = new ClassA(obj) //u r creating new instance
do
@Mock
ClassA myObject; //assuming u r using initMock or @InjectMocks
or
ClassA myObject = Mockito.mock(ClassA.class);
then Mock the behavior how u mock a method call
when(myObject.someMethod(any()))
.thenThrow(new SomeException());
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