Failed containsOnlyNulls Assertion for Null-Extracted List Elements

[laisbento]

Failed containsOnlyNulls Assertion for Null-Extracted List Elements

[joel-costigliola]

Thanks for reporting this @laisbento, we'll have a stab at it for the next release !

[laisbento]

Hello @joel-costigliola! Thanks for the explanation. I hadn't realized that flatExtracting existed. I've replaced for it in my tests and now everything is working as expected. I'll be using it from now on. :)

[joel-costigliola]

This is not a bug, when extracting multiple values AssertJ returns a list of Tuple, each tuple corresponding to the extracted values of the iterable under test.

The extracting javadoc shows the tuple role:

 // Build a list of TolkienCharacter, a TolkienCharacter has a name, and age and a Race (a specific class)
 // they can be public field or properties, both can be extracted.
 List<TolkienCharacter> fellowshipOfTheRing = new ArrayList<TolkienCharacter>();

 fellowshipOfTheRing.add(new TolkienCharacter("Frodo", 33, HOBBIT));
 fellowshipOfTheRing.add(new TolkienCharacter("Sam", 38, HOBBIT));
 fellowshipOfTheRing.add(new TolkienCharacter("Gandalf", 2020, MAIA));
 fellowshipOfTheRing.add(new TolkienCharacter("Legolas", 1000, ELF));
 fellowshipOfTheRing.add(new TolkienCharacter("Pippin", 28, HOBBIT));
 fellowshipOfTheRing.add(new TolkienCharacter("Gimli", 139, DWARF));
 fellowshipOfTheRing.add(new TolkienCharacter("Aragorn", 87, MAN);
 fellowshipOfTheRing.add(new TolkienCharacter("Boromir", 37, MAN));

 // let's verify 'name' and 'age' of some TolkienCharacter in fellowshipOfTheRing:
 assertThat(fellowshipOfTheRing).extracting("name", "age")
                                .contains(tuple("Boromir", 37),
                                          tuple("Sam", 38),
                                          tuple("Legolas", 1000));

the contains assertion following extracting works on tuples.

In your case, I'm guessing what you wanted to do is to check the elements of the extracted fields, this is possible with flatExtracting that "flattens" the tuples values, here's the javadoc:

 // values are extracted in order and flattened: age1, name1, age2, name2, age3 ...
 assertThat(fellowshipOfTheRing).flatExtracting("age", "name")
                                .contains(33 ,"Frodo",
                                          1000, "Legolas",
                                          87, "Aragorn");

No tuples used with flatExtracting, try this:

    assertThat(testList).flatExtracting("fullNames", "ages")
                        .containsOnlyNulls(); 

[joel-costigliola]

@laisbento I'm closing this issue, but feel free to comment on it, and we'll reopen it if necessary.