re-add TsSeconds for RustcDecodable

I think it's a terrible API, but AFAIK rustc-serialize doesn't support anything
like serde's `with` attribute.

I think it would be better to just not include this API at all and require that
people who want to use this move to serde, which is the recommended rust
encoding/decoding library.

src/datetime.rs

@@ -477,6 +477,35 @@ fn test_decodable_json<FUTC, FFixed, FLocal, E>(utc_from_str: FUTC,
     assert!(fixed_from_str(r#""2014-07-32T12:34:06Z""#).is_err());
 }
 
+#[cfg(all(test, feature = "rustc-serialize"))]
+fn test_decodable_json_timestamps<FUTC, FFixed, FLocal, E>(utc_from_str: FUTC,
+                                                           fixed_from_str: FFixed,
+                                                           local_from_str: FLocal)
+    where FUTC: Fn(&str) -> Result<TsSeconds<UTC>, E>,
+          FFixed: Fn(&str) -> Result<TsSeconds<FixedOffset>, E>,
+          FLocal: Fn(&str) -> Result<TsSeconds<Local>, E>,
+          E: ::std::fmt::Debug
+{
+    fn norm<Tz: TimeZone>(dt: &Option<DateTime<Tz>>) -> Option<(&DateTime<Tz>, &Tz::Offset)> {
+        dt.as_ref().map(|dt| (dt, dt.offset()))
+    }
+
+    assert_eq!(norm(&utc_from_str("0").ok().map(DateTime::from)),
+               norm(&Some(UTC.ymd(1970, 1, 1).and_hms(0, 0, 0))));
+    assert_eq!(norm(&utc_from_str("-1").ok().map(DateTime::from)),
+               norm(&Some(UTC.ymd(1969, 12, 31).and_hms(23, 59, 59))));
+
+    assert_eq!(norm(&fixed_from_str("0").ok().map(DateTime::from)),
+               norm(&Some(FixedOffset::east(0).ymd(1970, 1, 1).and_hms(0, 0, 0))));
+    assert_eq!(norm(&fixed_from_str("-1").ok().map(DateTime::from)),
+               norm(&Some(FixedOffset::east(0).ymd(1969, 12, 31).and_hms(23, 59, 59))));
+
+    assert_eq!(*fixed_from_str("0").expect("0 timestamp should parse"),
+               UTC.ymd(1970, 1, 1).and_hms(0, 0, 0));
+    assert_eq!(*local_from_str("-1").expect("-1 timestamp should parse"),
+               UTC.ymd(1969, 12, 31).and_hms(23, 59, 59));
+}
+
 #[cfg(feature = "rustc-serialize")]
 mod rustc_serialize {
     use std::fmt;
@@ -565,6 +594,11 @@ mod rustc_serialize {
         super::test_decodable_json(json::decode, json::decode, json::decode);
     }
 
+    #[test]
+    fn test_decodable_timestamps() {
+        super::test_decodable_json_timestamps(json::decode, json::decode, json::decode);
+    }
+
 }
 
 /// Ser/de helpers

src/naive/datetime.rs

@@ -1443,6 +1443,23 @@ fn test_decodable_json<F, E>(from_str: F)
     assert!(from_str(r#"null"#).is_err());
 }
 
+
+#[cfg(all(test, feature = "rustc-serialize"))]
+fn test_decodable_json_timestamp<F, E>(from_str: F)
+    where F: Fn(&str) -> Result<TsSeconds, E>, E: ::std::fmt::Debug
+{
+    assert_eq!(
+        *from_str("0").unwrap(),
+        NaiveDate::from_ymd(1970, 1, 1).and_hms(0, 0, 0),
+        "should parse integers as timestamps"
+    );
+    assert_eq!(
+        *from_str("-1").unwrap(),
+        NaiveDate::from_ymd(1969, 12, 31).and_hms(23, 59, 59),
+        "should parse integers as timestamps"
+    );
+}
+
 #[cfg(feature = "rustc-serialize")]
 mod rustc_serialize {
     use super::{NaiveDateTime, TsSeconds};
@@ -1480,6 +1497,12 @@ mod rustc_serialize {
         super::test_decodable_json(json::decode);
     }
 
+    #[test]
+    fn test_decodable_timestamps() {
+        super::test_decodable_json_timestamp(json::decode);
+
+    }
+
 }
 
 /// Tools to help serializing/deserializing NaiveDateTimes