What is the test for awarding attorney's fees in a Title VII case?

Title VII provides that "the court, in its discretion, may allow the prevailing party [in litigation under Title VII] . . . a reasonable attorney's fee . . . as part of the costs." 42 U.S.C. 2000e-5(k).⁵ We review a district court's award of attorney's fees for abuse of discretion. See LeBlanc-Sternberg v. Fletcher, 143 F.3d 748, 757 (2d Cir. 1998). Despite this highly deferential standard of review, "[a] district court necessarily abuses its discretion if it bases its ruling on an erroneous view of the law or on a clearly erroneous assessment of the record." Id.