Fix typo in tests_require
(transplanted from 73ce95a4c5acf619191264613b1afb2b91cd921f)

--HG--
extra : transplant_source : s%CE%95%A4%C5%AC%F6%19%19%12da%3B%1A%FB%2B%91%CD%92%1F
create branch 1.6

--HG--
branch : 1.6
close branch 1.6

--HG--
branch : 1.6
extra : close : 1