JFT mock tests are created based on the content of Irodori (vocabulary, kanji, and sentence patterns)

JFT mock tests from Gokaku Nihongo are created based on the Irodori textbook.

The official JFT-Basic website also recommends studying Irodori as preparation for the exam.

See: JFT-Basic Website – Hint for Learning

JFT mock tests from Gokaku Nihongo use Irodori and its official supplementary materials (such as vocabulary lists, kanji lists, and sentence pattern lists), and follow the official exam format.
This makes them a practical and efficient tool for test preparation.