[R-Forge #2156] test.data.table() should set locale to English one for duration of tests

[arunsrinivasan]

Submitted by: Matt Dowle; Assigned to: Nobody; R-Forge link

As reported here :

http://lists.r-forge.r-project.org/pipermail/datatable-help/2012-July/001233.html

Doing this should also allow the tests of non ascii characters to be added back, to pass on CRAN's Mac.

So it should not be Sys.setlocale("LCTYPE","") because the default might be non-English. Needs to be explicitly English UTF-8, and the name for it might be different for each OS.