What is the test for a hostile work environment claim?

"A hostile work environment claim requires a showing [1] that the harassment was sufficiently severe or pervasive to alter the conditions of the victim's employment and create an abusive working environment, and [2] that a specific basis exists for imputing the objectionable conduct to the employer." Alfano v. Costello, 294 F.3d 365, 373 (2d Cir. 2002) (citation and quotation marks omitted). Isolated incidents generally "do not meet the threshold of severity or pervasiveness," id. at 374, but a single act will suffice if it is so severe that it "work[s] a transformation of the plaintiff's workplace," id. "To decide whether the threshold has been reached, courts examine the case-specific circumstances in their totality and evaluate the severity, frequency, and degree of the abuse." Id.