+// test: echo -e 'set (1, 2, -5, 6, -8, 9, -2, 23, 4)\nord\nshow' | calc.exe | grep -q 'stack: -8 -5 -2 1 2 4 6 9 23'
+// test: echo -e 'set (1, 2, -5, 6, -8, 9, -2, 23, 4)\nmin (5, -3)\nmax (-1)\nmean (1, 2)\nvar (1, 2)\nmin\nmean\nmed\nmax\nprod\nsum\nvar' | calc.exe | awk 'BEGIN { split("9 -3 -1 1.5 0.5 -8 3.33333 2 23 -794880 30 73.3333", v) } /=>/ { for (i in v) if ($2 == v[i]) n++ } END { exit n != 12 }'
+// test: echo -e 'set (1, 2, -5, 6, -8, 9, -2, 23, 4)\nmin (5, -3)\nmax (-1)\nmin\nmean\nmed\nmax\nord\nprod\nsum\nvar\nquit' | calc.exe -n -v 3 | grep -q bye
+// test: echo -e 'min\nmean\nmed\nmax\nprod\nsum\nvar\nord\nset (1)\nord' | calc.exe -n | grep -c error | xargs test 9 =
+// test: echo -e 'prog (1, cos(pi * arg (1))) / 4' | calc.exe | grep -c error | xargs test 1 =