Preserve time zone offset when deserializing times

lib/psych/scalar_scanner.rb

@@ -143,7 +143,7 @@ def parse_time string
         offset += ((tz[1] || 0) * 60)
       end
 
-      klass.at((time - offset).to_i, us)
+      klass.new(yy, m, dd, hh, mm, ss+us/(1_000_000r), offset)
     end
   end
 end

test/psych/test_date_time.rb

@@ -9,10 +9,41 @@ def test_negative_year
       assert_cycle time
     end
 
+    def test_usec
+      time = Time.utc(2017, 4, 13, 12, 0, 0, 5)
+      assert_cycle time
+    end
+
+    def test_non_utc
+      time = Time.new(2017, 4, 13, 12, 0, 0.5, "+09:00")
+      assert_cycle time
+    end
+
+    def test_timezone_offset
+      times = [Time.new(2017, 4, 13, 12, 0, 0, "+09:00"),
+               Time.new(2017, 4, 13, 12, 0, 0, "-05:00")]
+      cycled = Psych::load(Psych.dump times)
+      assert_match(/12:00:00 \+0900/, cycled.first.to_s)
+      assert_match(/12:00:00 -0500/,  cycled.last.to_s)
+    end
+
     def test_new_datetime
       assert_cycle DateTime.new
     end
 
+    def test_datetime_non_utc
+      dt = DateTime.new(2017, 4, 13, 12, 0, 0.5, "+09:00")
+      assert_cycle dt
+    end
+
+    def test_datetime_timezone_offset
+      times = [DateTime.new(2017, 4, 13, 12, 0, 0, "+09:00"),
+               DateTime.new(2017, 4, 13, 12, 0, 0, "-05:00")]
+      cycled = Psych::load(Psych.dump times)
+      assert_match(/12:00:00\+09:00/, cycled.first.to_s)
+      assert_match(/12:00:00-05:00/,  cycled.last.to_s)
+    end
+
     def test_invalid_date
       assert_cycle "2013-10-31T10:40:07-000000000000033"
     end