Finish gigasecond

gigasecond/src/lib.rs

@@ -1,6 +1,8 @@
 use time::PrimitiveDateTime as DateTime;
+use time::Duration;
 
 // Returns a DateTime one billion seconds after start.
 pub fn after(start: DateTime) -> DateTime {
-    unimplemented!("What time is a gigasecond later than {}", start);
+    let gigasec:i64 = 1000000000;
+    start.saturating_add(Duration::seconds(gigasec))
 }

gigasecond/tests/gigasecond.rs

@@ -20,7 +20,6 @@ fn test_date() {
 }
 
 #[test]
-#[ignore]
 fn test_another_date() {
     let start_date = dt(1977, 6, 13, 0, 0, 0);
 
@@ -28,7 +27,6 @@ fn test_another_date() {
 }
 
 #[test]
-#[ignore]
 fn test_third_date() {
     let start_date = dt(1959, 7, 19, 0, 0, 0);
 
@@ -36,7 +34,6 @@ fn test_third_date() {
 }
 
 #[test]
-#[ignore]
 fn test_datetime() {
     let start_date = dt(2015, 1, 24, 22, 0, 0);
 
@@ -44,7 +41,6 @@ fn test_datetime() {
 }
 
 #[test]
-#[ignore]
 fn test_another_datetime() {
     let start_date = dt(2015, 1, 24, 23, 59, 59);