expected <- eval(parse(text="structure(c(15897600, 31536000, 31536000, 31536000, 31622400, 31536000, 31536000, 31536000, 47260800, 31536000, 31536000, 63158400, 78969600, 63158400, 31536000, 47260800, 31536000, 31536000, 47433600, 47260800, 47433600, 0, 0, 0), units = \"secs\", class = \"difftime\")"));               
test(id=0, code={               
argv <- eval(parse(text="list(structure(c(94694400, 126230400, 157766400, 189302400, 220924800, 252460800, 283996800, 315532800, 362793600, 394329600, 425865600, 489024000, 567993600, 631152000, 662688000, 709948800, 741484800, 773020800, 820454400, 867715200, 915148800, 1136073600, 1230768000, 1341100800), class = c(\"POSIXct\", \"POSIXt\")), structure(c(78796800, 94694400, 126230400, 157766400, 189302400, 220924800, 252460800, 283996800, 315532800, 362793600, 394329600, 425865600, 489024000, 567993600, 631152000, 662688000, 709948800, 741484800, 773020800, 820454400, 867715200, 1136073600, 1230768000, 1341100800), class = c(\"POSIXct\", \"POSIXt\")))"));               
do.call(`-`, argv);               
}, o=expected);               

