F1 F2 F3 F4
1000 1000.0 3 empty
1000 1000.0 3 1-space
1000 1000.001 3 2-spaces
1000 1001 abc 3 no space
1000 999.999 abc 3 space prefix
1000 999 abc 3 space suffix
1000 999.9999 a 3 space prefix&suffix
999.999 1000 x x
999.999 1000.999 x x
1000 1001.1 x x
-999.99 -1000 x x
-999.98 -1000 x x
-999.99 1000 x x
999.99 -1000 x x