Refactoring to allow for a more flexible API.

src/custom_error.rs

@@ -1,6 +1,4 @@
-pub use std::convert;
-pub use std::io::prelude::*;
-
+use std::convert;
 use std::error;
 use std::fmt;
 use std::io;
@@ -14,8 +12,12 @@ pub struct Error {
 }
 
 impl Error {
+    /// Initializes a new error with a description and optional detail string.
     pub fn new(descr: &'static str, detail: Option<String>) -> Error {
-        Error { descr: descr, detail: detail }
+        Error {
+            descr: descr,
+            detail: detail,
+        }
     }
 }
 
@@ -23,17 +25,21 @@ impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self.detail {
             None => write!(f, "{}", self.descr),
-            Some(ref detail) => write!(f, "{} ({})", self.descr, detail)
+            Some(ref detail) => write!(f, "{} ({})", self.descr, detail),
         }
     }
 }
 
 impl error::Error for Error {
-    fn description(&self) -> &str { self.descr }
-    fn cause(&self) -> Option<&error::Error> { None }
+    fn description(&self) -> &str {
+        self.descr
+    }
+    fn cause(&self) -> Option<&error::Error> {
+        None
+    }
 }
 
-impl convert::From<Error> for io::Error {
+impl From<Error> for io::Error {
     fn from(me: Error) -> io::Error {
         io::Error::new(io::ErrorKind::Other, me)
     }
@@ -42,30 +48,47 @@ impl convert::From<Error> for io::Error {
 /// Returns an `io::Error` from description string and optional detail string.
 /// Particularly useful in `Result` expressions.
 pub fn other_io_err(descr: &'static str, detail: Option<String>) -> io::Error {
-    convert::From::from(
-        Error::new(descr, detail)
-    )
+    convert::From::from(Error::new(descr, detail))
 }
 
 /// maps a `ParseIntError` to an `io::Error`
 pub fn pie2io(p: num::ParseIntError) -> io::Error {
-    convert::From::from(
-        Error::new("Integer parsing error", Some(p.to_string()))
-    )
+    convert::From::from(Error::new("Integer parsing error", Some(p.to_string())))
 }
 
-#[test]
-fn test_custom_error() {
-    let desc = "Boring error description";
-    let detail = "More of it";
-    let ewd = Error::new(desc, Some(detail.to_string()));
+#[cfg(test)]
+mod tests_custom_err {
+    use std::error;
+    use custom_error;
 
-    assert_eq!(error::Error::description(&ewd), desc);
-    match error::Error::cause(&ewd) {
-        Some(_)  => assert!(false),
-        None   => assert!(true),
+    #[test]
+    fn test_custom_error() {
+        let desc = "Boring error description";
+        let detail = "More of it";
+        let ewd = custom_error::Error::new(desc, Some(detail.to_string()));
+
+        assert_eq!(error::Error::description(&ewd), desc);
+        match error::Error::cause(&ewd) {
+            Some(_) => assert!(false),
+            None => assert!(true),
+        }
+        let _formated_err = format!("{}", ewd);
+        let ewod = custom_error::Error::new(desc, None);
+        let _formated_err = format!("{}", ewod);
+    }
+}
+
+#[cfg(test)]
+mod tests_std_err {
+    use std::error::Error;
+    use custom_error::pie2io;
+
+    #[test]
+    fn test_parse_errors() {
+        let nan = "2a".to_string();
+        match nan.parse::<u8>().map_err(pie2io) {
+            Ok(_) => assert!(false),
+            Err(x) => assert_eq!("Integer parsing error", x.description()),
+        }
     }
-    let _formated_err = format!("{}", ewd);
-    let ewod = Error::new(desc, None);
-    let _formated_err = format!("{}", ewod);
 }