LocalDateConverterTest: added negative test for invalid string input
(DateTimeParseException).
CategoryDaoTest, LocationDaoTest: added getAll tests with multiple
entities to verify complete retrieval.
ItemDaoTest: fixed getExpiringSoon test (was calling non-existent
getExpiringSoon(Int) instead of getExpiringSoonByCutoff(LocalDate));
added getAll, getById positive, and getById negative tests.
JsonRoundtripTest (new): verifies lossless export-import roundtrip
with multiple items covering all fields, nullable fields (null
kcalPer100g, null expiryDate), and empty database edge case.
TestFakes (new): extracted shared Fake DAO implementations from
ImportExportRepositoryImplTest to avoid private class redeclaration
errors across test files in the same package.
Closes#22
0c1e06afca