Joachim Raff's Op. 157 is likely a pair of Romantic character pieces, with one potentially being a spirited and technically demanding study.
Developing evenness and power in rapid scalar passages is essential.
2 Piano Pieces (Op.157) is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 6.
You should be comfortable at Henle level 4 — meaning you can already play level 3–4 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of 2 Piano Pieces (Op.157) lasts about 5 minutes.
2 Piano Pieces (Op.157) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.