New validation.

src/lib.rs

@@ -192,10 +192,10 @@ impl AsciiTable {
     fn valid(&self, data: &Vec<Vec<String>>, num_cols: usize) -> bool {
         if data.len() == 0 {
             false
-        } else if self.max_width < 4 {
-            false
         } else if num_cols == 0 {
             false
+        } else if self.max_width < ((num_cols - 1) * 3) + 4 {
+            false
         } else {
             true
         }

src/test.rs

@@ -118,7 +118,7 @@ fn smallest_cell2() {
 #[test]
 fn smallest_cube() {
     let config = AsciiTable {
-        max_width: 4,
+        max_width: 10,
         ..AsciiTable::default()
     };
     let input = vec![&[1, 2, 3], &[4, 5, 6], &[7, 8, 9]];
@@ -233,7 +233,7 @@ fn smallest_cell_with_header2() {
 #[test]
 fn smallest_cube_with_header() {
     let mut config = AsciiTable {
-        max_width: 4,
+        max_width: 10,
         ..AsciiTable::default()
     };
     config.columns.insert(0, Column {header: "abc".to_string(), ..Column::default()});