LONDON—Rolls-Royce expects to commence a new round of tests soon to further boost the performance of its Boeing 787-powering Trent 1000 engine as it looks to regain market share on the widebody.

Last year, the UK-headquartered engine maker disclosed a £1 billion ($1.26 billion) investment to improve durability across its Trent portfolio, including the 40% time-on-wing improvement target.

Rolls-Royce has recently unveiled a significant development in its partnership with IndiGo, a prominent Indian airline, with an agreement to supply 60 Trent XWB-84 engines. This marks the first ...