Assert identity with AssertJ or JUnit

Question

Edit II

Basically, the question is if there's an AssertJ (preferred) or JUnit assertion for:

objA == objB

Edit I

My class under test (CUT) extends JAXB's XmlAdapter. When unmarshalling a XML file, it should guarantee that equal objects exist exactly once. In order to verify this, my test currently looks like this (in the example the standard ctor creates equal objects):

MyType obj = cut.unmarshal(new MyType());
assertThat(cut.unmarshal(new MyType()) == obj).isTrue();

Is there a way to explicitly assert identity with AssertJ or JUnit?

Original Post

My class under test (CUT) has a method (e.g. foo) which should guarantee that returned objects—that are equal—exist exactly once. Currently, I'm using the following assert statement:

assertThat(cut.foo() == obj).isTrue();

Is there a way to explicitly assert identity with AssertJ or JUnit?

What do you mean with "object exists only once". Any reference points to a unique object?! Do you mean: foo() should return a **different** object each time you call it?! — GhostCat, Nov 02 '16 at 10:41
There's no way to confirm that some other copy doesn't exist floating off in another corner of the JVM. — chrylis -cautiouslyoptimistic-, Nov 02 '16 at 10:49
@chrylis I know, I'm only talking about objects returned by `foo`. — beatngu13, Nov 02 '16 at 10:52
This will be fine unless you want to ensure that identical duplicates exist. You may find it more readable to use `assertSame()` http://junit.sourceforge.net/javadoc/org/junit/Assert.html — d.j.brown, Nov 02 '16 at 10:56
@chrylis Exactly, thanks! Would you mind adding this as an answer? — beatngu13, Nov 02 '16 at 10:56

score 6 · Accepted Answer · answered Nov 02 '16 at 11:28

6

If you are using AssertJ, you can use the isSameAs method to compare object identity:

assertThat(cut.foo()).isSameAs(obj);

answered Nov 02 '16 at 11:28

chrylis -cautiouslyoptimistic-

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Assert identity with AssertJ or JUnit

Edit II

Edit I

Original Post

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