fix problem with runtests.jl

Author: ablaom

test/runtests.jl

@@ -13,7 +13,7 @@ files = isempty(ARGS) ? test_files : ARGS
 for file in files
     quote
         @testset $file begin
-            include($file*".jl")
+            include($file)
         end
     end |> eval
 end