CmdStart: Stop previous interval at given start time

- End time of previous open interval now set to start time given on
  cmd line in CmdStart.

src/commands/CmdStart.cpp

@@ -45,9 +45,12 @@ int CmdStart (
   auto latest = getLatestInterval (database);
   if (latest.range.is_open ())
   {
-    // Stop it.
+    // Stop it, at the given start time, if applicable.
     Interval modified {latest};
-    modified.range.end = Datetime ();
+    if (filter.range.start.toEpoch () != 0)
+      modified.range.end = filter.range.start;
+    else
+      modified.range.end = Datetime ();
 
     // Update database.
     database.deleteInterval (latest);

test/start.t

@@ -79,6 +79,16 @@ class TestStart(TestCase):
         self.assertIn("Recorded foo", out)
         self.assertIn("Tracking bar", out)
 
+    def test_start_with_open_interval_timed(self):
+        """Test timed start with already open interval, which should be auto-stopped 
+        at given datetime"""
+        self.t("start 2016-01-01T00:00:00 foo")
+        code, out, err = self.t("start 2016-01-01T01:00:00 bar")
+        self.assertIn("Recorded foo", out)
+        self.assertIn("Tracking bar", out)
+
+        self.assertIn("Ended              01:00:00",out)
+
 if __name__ == "__main__":
     from simpletap import TAPTestRunner
     unittest.main(testRunner=TAPTestRunner())