What is the test for equitable tolling in a limitation statute?

While "[o]rdinarily limitations statutes use fairly simple language, which can often plausibly read as containing an implied 'equitable tolling' exception" (United States v. Brockamp (1997) 519 U.S. 347, 350 [136 L.Ed.2d 818, 822]), "[e]quitable tolling is not permissible where it is inconsistent with the text of the relevant statute." (United States v. Beggerly (1998) 524 U.S. 38, __ [141 L.Ed.2d 32, 41]; United States v. Brockamp, supra, 519 U.S. at pp. 350-351 [136 L.Ed.2d at pp. 822-823].)