Add: Implement Display trait for Category

This allows to convert the category directly to a string.

rust/nvtcache/src/nvt.rs

@@ -1,6 +1,6 @@
-use crate::dberror::DbError;
 use crate::dberror::Result;
 use std::collections::LinkedList;
+use std::fmt;
 
 ///Alias for time stamps
 type TimeT = i64;
@@ -20,6 +20,24 @@ pub enum Category {
     ActEnd,
 }
 
+impl fmt::Display for Category {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Category::ActInit => write!(f, "0"),
+            Category::ActScanner => write!(f, "1"),
+            Category::ActSettings => write!(f, "2"),
+            Category::ActGatherInfo => write!(f, "3"),
+            Category::ActAttack => write!(f, "4"),
+            Category::ActMixedAttack => write!(f, "5"),
+            Category::ActDestructiveAttack => write!(f, "6"),
+            Category::ActDenial => write!(f, "7"),
+            Category::ActKillHost => write!(f, "8"),
+            Category::ActFlood => write!(f, "9"),
+            Category::ActEnd => write!(f, "10"),
+        }
+    }
+}
+
 /// Structure to store NVT preferences
 #[derive(Debug)]
 pub struct NvtPref {

rust/nvtcache/tests/nvt_tests.rs

@@ -1,5 +1,5 @@
 use nvtcache::dberror::Result;
-use nvtcache::nvt::{Nvt, NvtRef};
+use nvtcache::nvt::{Category, Nvt, NvtRef};
 
 #[cfg(test)]
 mod test {
@@ -105,4 +105,11 @@ mod test {
 
         Ok(())
     }
+
+    #[test]
+    fn test_category_from_trait() {
+        let cat = Category::ActEnd;
+
+        assert_eq!(cat.to_string(), "10");
+    }
 }