+// test: echo -e 'print (1)\nquit' | calc.exe -v 3 | grep -q Print
+// test: echo -e 'si\t\t (pi / 2)' | calc.exe | grep -q '=> 1'
+// test: echo -e '1 + 1;\nans + 1' | calc.exe | grep -qv 2
+// test: echo -e 'mem (3)\nsto (4, pi)' | calc.exe | grep -q "invalid index"
+// test: echo -e 'sto (2, 3)\nmem (2)\ndisp' | calc.exe | grep -q 'storage: 0 3$'
+// test: echo -e 'disp' | calc.exe | grep -q "storage: 0 0 0 0 0 0 0 0 0 0"
+// test: echo -e 'sto (3, 10)\ndisp' | calc.exe | grep -q "storage: 0 0 10 0 0 0 0 0 0 0"
+// test: echo -e 'rcl (3)\ndisp' | calc.exe | grep -q "storage: 0 0 0 0 0 0 0 0 0 0"
+// test: echo -e 'inc (2)\ndisp' | calc.exe | grep -q "storage: 0 1 0 0 0 0 0 0 0 0"
+// test: echo -e 'dec (2)\ndisp' | calc.exe | grep -q "storage: 0 -1 0 0 0 0 0 0 0 0"
+// test: echo -e 'sto (3, pi)\nclr\ndisp' | calc.exe | grep -q "storage: 0 0 0 0 0 0 0 0 0 0"
+// test: echo -e 'mem (3)\nclr\nquit' | calc.exe -v 3 | grep -q Clear
+// test: echo -e 'prog (2, 2, {rcl (2) - rcl (1)})\nprog (1, 1, {cos (rcl (1)^2)})\ncall (1, pi/6)\nprog (2, 1, {rcl (1) * 3})\ncall (2, 1, 2)\nls' | calc.exe
+// test: echo -e 'prog (1, 2, {rcl (2) - rcl (1)})\ncall (1, 2, 3)\nls\nedit (1)\nprog (1, 2, {rcl (2) + rcl (1)})\nedit (1)\ndel (1)\nquit' | calc.exe -v 3 |grep -q bye
+// test: echo -e 'prog (2, 2, {rcl (2) - rcl (1)})\nprog (3, 1, cos(rcl (1) * pi / 3))\ncall (1, 2, 3)\nls\nedit (1)\ndel (1)\n\ndel (2)\ncall (2, 1, 4)' | calc.exe | grep -c error | xargs test 4 =
+
+// Gauss sequence
+// test: echo -e '{sto (1, 0), sto (10, 0), while (inc (10) < 100, {sto (1, rcl (1) + rcl (10)), print (rcl (1))})};' | calc.exe | grep -q '=> 5050'