GSAFD, 2000 (Didactic fiction: Use for works that are primarily intended to teach a lesson)
Baldick, C. Oxford dictionary of literary terms, c2008 (didactic: instructive; designed to impart information, advice, or some doctrine of morality or philosophy. In the broadest sense, most allegories and satires implying a moral or political view may be regarded as didactic, along with many other kinds of work in which the theme embodies some philosophical or other belief of the author. A stricter definition would confine the term to those works that explicitly tell the reader what they should do.)
Henry, L. The fiction dictionary, c1995 (Didactic fiction: usually a pejorative term describing fiction whose goal is to teach the reader something; fiction that tries to teach the reader to feel a certain way about some subject, rather than to impart objective information.)

Fiction that is intended to be instructional.