std: Add tests for time module

Tested on OSX and Windows.

src/libstd/time.rs

@@ -45,3 +45,50 @@ in seconds since an unspecified epoch.
 fn precise_time_s() -> float {
     ret (precise_time_ns() as float) / 1000000000.;
 }
+
+#[cfg(test)]
+mod tests {
+    import task;
+
+    #[test]
+    fn test_get_time() {
+        const some_recent_date: u32 = 1325376000u32; // 2012-01-01T00:00:00Z
+        const some_future_date: u32 = 1577836800u32; // 2020-01-01T00:00:00Z
+
+        let tv1 = get_time();
+        log(debug, "tv1=" + uint::str(tv1.sec as uint) + " sec + "
+                   + uint::str(tv1.usec as uint) + " usec");
+
+        assert tv1.sec > some_recent_date;
+        assert tv1.usec < 1000000u32;
+
+        let tv2 = get_time();
+        log(debug, "tv2=" + uint::str(tv2.sec as uint) + " sec + "
+                   + uint::str(tv2.usec as uint) + " usec");
+
+        assert tv2.sec >= tv1.sec;
+        assert tv2.sec < some_future_date;
+        assert tv2.usec < 1000000u32;
+        if tv2.sec == tv1.sec {
+            assert tv2.usec >= tv1.usec;
+        }
+    }
+
+    #[test]
+    fn test_precise_time() {
+        let s0 = precise_time_s();
+        let ns1 = precise_time_ns();
+
+        log(debug, "s0=" + float::to_str(s0, 9u) + " sec");
+        assert s0 > 0.;
+        let ns0 = (s0 * 1000000000.) as u64;
+        log(debug, "ns0=" + u64::str(ns0) + " ns");
+
+        log(debug, "ns1=" + u64::str(ns1) + " ns");
+        assert ns1 >= ns0;
+
+        let ns2 = precise_time_ns();
+        log(debug, "ns2=" + u64::str(ns2) + " ns");
+        assert ns2 >= ns1;
+    }
+}