Added datetime field.

src/field.rs

@@ -1,3 +1,4 @@
+use chrono::prelude::*;
 use std::fmt;
 use uuid::Uuid;
 
@@ -5,6 +6,7 @@ use uuid::Uuid;
 pub enum Field {
     Static(String),
     Uuid(Uuid),
+    DateTime(DateTime<Utc>),
 }
 
 impl Field {
@@ -14,6 +16,13 @@ impl Field {
             _ => Err("not a uuid".to_string()),
         }
     }
+
+    pub fn to_datetime(&self) -> Result<DateTime<Utc>, String> {
+        match self {
+            Field::DateTime(data) => Ok(data.clone()),
+            _ => Err("not a datetime".to_string()),
+        }
+    }
 }
 
 impl From<String> for Field {
@@ -42,11 +51,18 @@ impl From<Uuid> for Field {
     }
 }
 
+impl From<DateTime<Utc>> for Field {
+    fn from(value: DateTime<Utc>) -> Self {
+        Field::DateTime(value)
+    }
+}
+
 impl fmt::Display for Field {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             Field::Uuid(data) => write!(f, "{}", data),
             Field::Static(data) => write!(f, "{}", data),
+            Field::DateTime(data) => write!(f, "{}", data),
         }
     }
 }
@@ -148,4 +164,36 @@ mod fields {
             Err(_) => {}
         }
     }
+
+    #[test]
+    fn use_date_to_field() {
+        let expected = Utc::now();
+        let field: Field = expected.into();
+        match field {
+            Field::DateTime(result) => assert_eq!(result, expected),
+            _ => unreachable!("should have been date time"),
+        }
+    }
+
+    #[test]
+    fn from_datetime_field_to_string() {
+        let now = Utc::now();
+        let expected = now.to_string();
+        let field: Field = now.into();
+        assert_eq!(field.to_string(), expected);
+    }
+
+    #[test]
+    fn from_field_to_datetime() {
+        let now = Utc::now();
+        let field: Field = now.into();
+        assert_eq!(field.to_datetime().unwrap(), now);
+    }
+
+    #[test]
+    fn from_static_field_to_datatime() {
+        let txt = "Not gonna work.";
+        let field: Field = txt.into();
+        assert!(field.to_datetime().is_err(), "should not return a value");
+    }
 }