expected <- eval(parse(text="NULL"));                   
test(id=0, code={                   
argv <- eval(parse(text="list(c(NA, NA, \"/home/lzhao/tmp/RtmpGUHe0I/R.INSTALL2aa51f3e9d31/lattice/R/histogram.R\", \"/home/lzhao/tmp/RtmpGUHe0I/R.INSTALL2aa51f3e9d31/lattice/R/histogram.R\"), \"levels\")"));                   
do.call(`attr`, argv);                   
}, o=expected);                   

