TI-6: Exception after shortening task.

- Thanks to Sergey Trofimov.

ChangeLog

@@ -11,6 +11,8 @@
           (thanks to Tomas Babej).
 - TI-5    Unicode tags not working.
           (thanks to Sergey Trofimov).
+- TI-6    Exception after shortening task.
+          (thanks to Sergey Trofimov).
 - Added 'continue' command.
 - Added 'diagnostics' command.
 - Added 'export' command.

src/commands/CmdShorten.cpp

@@ -67,6 +67,8 @@ int CmdShorten (
       if (! i.range.is_open ())
       {
         Duration dur (delta);
+        if (dur < (i.range.end - i.range.start))
+        {
           i.range.end -= dur.toTime_t ();
 
           database.modifyInterval (tracked[tracked.size () - id], i);
@@ -74,6 +76,15 @@ int CmdShorten (
           // Feedback.
           std::cout << "Shortened @" << id << " by " << dur.formatHours () << '\n';
         }
+        else
+          std::cout << "Cannot shorten interval @"
+                    << id
+                    << " by "
+                    << dur.formatHours ()
+                    << " because it is only "
+                    << Duration (i.range.end - i.range.start).formatHours ()
+                    << " in length.\n";
+      }
       else
         std::cout << "Cannot shorten open interval @" << id << '\n';
     }

test/shorten.t

@@ -70,6 +70,21 @@ class TestShorten(TestCase):
 
 # TODO Add :adjust tests.
 
+class TestBug6(TestCase):
+    def setUp(self):
+        """Executed before each test in the class"""
+        self.t = Timew()
+
+    def test_over_shorten_closed_interval(self):
+        """TI-6: Exception after shortening task.
+
+           When an interval is shortened by an amount that exceeds it's length,
+           an assert is triggered, and should be an error instead.
+        """
+        self.t("track 2016-06-08T07:30:00 - 2016-06-08T07:35:00 foo")
+        code, out, err = self.t("shorten @1 10mins")
+        self.assertIn('Cannot shorten interval @1 by 0:10:00 because it is only 0:05:00 in length.', out)
+
 if __name__ == "__main__":
     from simpletap import TAPTestRunner
     unittest.main(testRunner=TAPTestRunner())