Impl: Display trait for Playfield

Ref: Move new to tests and refactor tests in nested mod

src/main.rs

@@ -24,32 +24,31 @@ struct Field {
     value: Option<u32>,
 }
 
+use std::fmt;
 impl Playfield {
     fn new(size: usize) -> Playfield {
-        let fields = vec![
-            vec![
-                Field {
-                    possible_values: Vec::<u32>::new(),
-                    value: None
-                };
-                size
-            ];
-            size
-        ];
         Self {
-            fields,
+            fields: vec![vec![Field::default(); size]; size],
             open_fields: Vec::<u32>::new(),
         }
     }
 }
 
-impl Field {
-    fn new(value: u32) -> Field {
-        Self {
-            possible_values: Vec::<u32>::new(),
-            value: Some(value),
+impl fmt::Display for Playfield {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut result = String::new();
+        for row in &self.fields {
+            for field in row {
+                result += &field.value.unwrap_or_else(|| 0).to_string();
+                result += " ";
+            }
+            result += "\n";
         }
+        write!(f, "{}", result)
     }
+}
+
+impl Field {
     fn default() -> Field {
         Self {
             possible_values: Vec::<u32>::new(),
@@ -62,6 +61,8 @@ fn main() {
     let cli = Cli::parse();
 
     let playfield = parse_playfield(&cli.field, cli.field_size);
+
+    println!("Input:\n{}", playfield)
 }
 
 fn parse_playfield(field: &String, field_size: usize) -> Playfield {
@@ -105,50 +106,63 @@ fn is_right_field_size(field: &Vec<&str>, field_size: usize) -> bool {
 mod tests {
     use super::*;
 
-    #[test]
-    fn test_parse_field() {
-        let input = "1 2 3 0 0 0 3 2 1";
-        let field_size = 3;
-
-        let playfield = parse_playfield(&input.to_string(), field_size);
-
-        assert_eq!(
-            playfield,
-            Playfield {
-                fields: vec![
-                    vec![Field::new(1), Field::new(2), Field::new(3)],
-                    vec![Field::default(), Field::default(), Field::default()],
-                    vec![Field::new(3), Field::new(2), Field::new(1)]
-                ],
-                open_fields: vec![]
+    impl Field {
+        fn new(value: u32) -> Field {
+            Self {
+                possible_values: Vec::<u32>::new(),
+                value: Some(value),
             }
-        )
+        }
     }
 
-    #[test]
-    #[should_panic(expected = "Input must have dimension of size 2x2")]
-    fn test_parse_field_too_long_input() {
-        let input = "1 2 3 0 0 0 3 2 1";
-        let field_size = 2;
+    mod parse_field {
+        use super::super::*;
 
-        let _ = parse_playfield(&input.to_string(), field_size);
-    }
+        #[test]
+        fn simple() {
+            let input = "1 2 3 0 0 0 3 2 1";
+            let field_size = 3;
 
-    #[test]
-    #[should_panic(expected = "Input must have dimension of size 3x3")]
-    fn test_parse_field_too_short_input() {
-        let input = "1 2 3";
-        let field_size = 3;
+            let playfield = parse_playfield(&input.to_string(), field_size);
 
-        let _ = parse_playfield(&input.to_string(), field_size);
-    }
+            assert_eq!(
+                playfield,
+                Playfield {
+                    fields: vec![
+                        vec![Field::new(1), Field::new(2), Field::new(3)],
+                        vec![Field::default(), Field::default(), Field::default()],
+                        vec![Field::new(3), Field::new(2), Field::new(1)]
+                    ],
+                    open_fields: vec![]
+                }
+            )
+        }
 
-    #[test]
-    #[should_panic(expected = "Input must contain only digits followed by space")]
-    fn test_parse_field_wrong_character() {
-        let input = "1 2 3 0 0 0 3 2 a";
-        let field_size = 3;
+        #[test]
+        #[should_panic(expected = "Input must have dimension of size 2x2")]
+        fn too_long_input() {
+            let input = "1 2 3 0 0 0 3 2 1";
+            let field_size = 2;
 
-        let _ = parse_playfield(&input.to_string(), field_size);
+            let _ = parse_playfield(&input.to_string(), field_size);
+        }
+
+        #[test]
+        #[should_panic(expected = "Input must have dimension of size 3x3")]
+        fn too_short_input() {
+            let input = "1 2 3";
+            let field_size = 3;
+
+            let _ = parse_playfield(&input.to_string(), field_size);
+        }
+
+        #[test]
+        #[should_panic(expected = "Input must contain only digits followed by space")]
+        fn wrong_character() {
+            let input = "1 2 3 0 0 0 3 2 a";
+            let field_size = 3;
+
+            let _ = parse_playfield(&input.to_string(), field_size);
+        }
     }
 }