diff --git a/src/Duration.cpp b/src/Duration.cpp
index 583ad2b37..e833adfad 100644
--- a/src/Duration.cpp
+++ b/src/Duration.cpp
@@ -35,6 +35,59 @@
 #include "util.h"
 #include "Duration.h"
 
+static const char* durations[] =
+{
+  "annual",
+  "biannual",
+  "bimonthly",
+  "biweekly",
+  "biyearly",
+  "daily",
+  "days",
+  "day",
+  "d",
+  "fortnight",
+  "hours",
+  "hrs",
+  "h",
+  "minutes",
+  "mins",
+  "min",
+  "m",
+
+  "mnths",
+  "monthly",
+  "months",
+  "month",
+  "mos",
+  "mo",
+  "mths",
+
+  "quarterly",
+  "quarters",
+  "qrtrs",
+  "qtrs",
+  "q",
+  "seconds",
+  "secs",
+  "sec",
+  "s",
+  "semiannual",
+  "sennight",
+  "weekdays",
+  "weekly",
+  "weeks",
+  "wks",
+  "w",
+  "yearly",
+  "years",
+  "yrs",
+  "y",
+  "-",
+};
+
+#define NUM_DURATIONS   (sizeof (durations)   / sizeof (durations[0]))
+
 ////////////////////////////////////////////////////////////////////////////////
 Duration::Duration ()
 : mSecs (0)
@@ -42,6 +95,13 @@ Duration::Duration ()
 {
 }
 
+////////////////////////////////////////////////////////////////////////////////
+Duration::Duration (const Duration& other)
+{
+  mSecs     = other.mSecs;
+  mNegative = other.mNegative;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 Duration::Duration (time_t input)
 {
@@ -59,6 +119,8 @@ Duration::Duration (time_t input)
 
 ////////////////////////////////////////////////////////////////////////////////
 Duration::Duration (const std::string& input)
+: mSecs (0)
+, mNegative (false)
 {
   parse (input);
 }
@@ -73,7 +135,7 @@ Duration::operator time_t ()
 Duration::operator std::string ()
 {
   std::stringstream s;
-  s << (mNegative ? -mSecs : mSecs);
+  s << (mNegative ? - (long) mSecs : (long) mSecs);
   return s.str ();
 }
 
@@ -168,80 +230,39 @@ Duration::~Duration ()
 {
 }
 
+////////////////////////////////////////////////////////////////////////////////
+bool Duration::negative () const
+{
+  return mNegative;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 bool Duration::valid (const std::string& input) const
 {
   std::string lower_input = lowerCase (input);
 
+  // Assume the ordinal is 1, but look for an integer, just in case.
+  int value = 1;
+  Nibbler n (lower_input);
+  n.skipAll (' ');
+  n.getInt (value);
+  n.skipAll (' ');
+
+  if (value < 0)
+    value = -value;
+
+  std::string units;
+  n.getUntilEOS (units);
+
+  // Auto complete against all supported durations.
   std::vector <std::string> supported;
-  supported.push_back ("daily");       // TODO i18n
-  supported.push_back ("day");         // TODO i18n
-  supported.push_back ("weekly");      // TODO i18n
-  supported.push_back ("weekdays");    // TODO i18n
-  supported.push_back ("sennight");    // TODO i18n
-  supported.push_back ("biweekly");    // TODO i18n
-  supported.push_back ("fortnight");   // TODO i18n
-  supported.push_back ("monthly");     // TODO i18n
-  supported.push_back ("bimonthly");   // TODO i18n
-  supported.push_back ("quarterly");   // TODO i18n
-  supported.push_back ("biannual");    // TODO i18n
-  supported.push_back ("biyearly");    // TODO i18n
-  supported.push_back ("annual");      // TODO i18n
-  supported.push_back ("semiannual");  // TODO i18n
-  supported.push_back ("yearly");      // TODO i18n
+  for (unsigned int i = 0; i < NUM_DURATIONS; ++i)
+    supported.push_back (durations[i]);
 
   std::vector <std::string> matches;
-  if (autoComplete (lower_input, supported, matches) == 1)
+  if (autoComplete (units, supported, matches) == 1)
     return true;
 
-  // Support \s+ -? \d+ \s? s|secs?|m|mins?|h|hrs?|d|days?|wks?|mo|mths?|y|yrs?|-
-  // Note: Does not support a sign character.  That must be external to
-  // Duration.
-  Nibbler n (lower_input);
-  int value;
-
-  n.skipAll (' ');
-  n.skip ('-');
-
-  if (n.getUnsignedInt (value))
-  {
-    n.skipAll (' ');
-
-         if (n.getLiteral ("yrs")  && n.depleted ()) return true;
-    else if (n.getLiteral ("yr")   && n.depleted ()) return true;
-    else if (n.getLiteral ("y")    && n.depleted ()) return true;
-
-    else if (n.getLiteral ("qtrs") && n.depleted ()) return true;
-    else if (n.getLiteral ("qtr")  && n.depleted ()) return true;
-    else if (n.getLiteral ("q")    && n.depleted ()) return true;
-
-    else if (n.getLiteral ("mths") && n.depleted ()) return true;
-    else if (n.getLiteral ("mth")  && n.depleted ()) return true;
-    else if (n.getLiteral ("mo")   && n.depleted ()) return true;
-
-    else if (n.getLiteral ("wks")  && n.depleted ()) return true;
-    else if (n.getLiteral ("wk")   && n.depleted ()) return true;
-    else if (n.getLiteral ("w")    && n.depleted ()) return true;
-
-    else if (n.getLiteral ("days") && n.depleted ()) return true;
-    else if (n.getLiteral ("day")  && n.depleted ()) return true;
-    else if (n.getLiteral ("d")    && n.depleted ()) return true;
-
-    else if (n.getLiteral ("hrs")  && n.depleted ()) return true;
-    else if (n.getLiteral ("hr")   && n.depleted ()) return true;
-    else if (n.getLiteral ("h")    && n.depleted ()) return true;
-
-    else if (n.getLiteral ("mins") && n.depleted ()) return true;
-    else if (n.getLiteral ("min")  && n.depleted ()) return true;
-    else if (n.getLiteral ("m")    && n.depleted ()) return true;
-
-    else if (n.getLiteral ("secs") && n.depleted ()) return true;
-    else if (n.getLiteral ("sec")  && n.depleted ()) return true;
-    else if (n.getLiteral ("s")    && n.depleted ()) return true;
-
-    else if (n.getLiteral ("-")    && n.depleted ()) return true;
-  }
-
   return false;
 }
 
@@ -250,95 +271,98 @@ void Duration::parse (const std::string& input)
 {
   std::string lower_input = lowerCase (input);
 
-  std::vector <std::string> supported;
-  supported.push_back ("daily");        // TODO i18n
-  supported.push_back ("day");          // TODO i18n
-  supported.push_back ("weekly");       // TODO i18n
-  supported.push_back ("weekdays");     // TODO i18n
-  supported.push_back ("sennight");     // TODO i18n
-  supported.push_back ("biweekly");     // TODO i18n
-  supported.push_back ("fortnight");    // TODO i18n
-  supported.push_back ("monthly");      // TODO i18n
-  supported.push_back ("bimonthly");    // TODO i18n
-  supported.push_back ("quarterly");    // TODO i18n
-  supported.push_back ("biannual");     // TODO i18n
-  supported.push_back ("biyearly");     // TODO i18n
-  supported.push_back ("annual");       // TODO i18n
-  supported.push_back ("semiannual");   // TODO i18n
-  supported.push_back ("yearly");       // TODO i18n
+  // Assume the ordinal is 1, but look for an integer, just in case.
+  int value = 1;
+  Nibbler n (lower_input);
+  n.skipAll (' ');
+  n.getInt (value);
 
-  std::vector <std::string> matches;
-  if (autoComplete (lower_input, supported, matches) == 1)
+  n.skipAll (' ');
+
+  if (value < 0)
   {
-    std::string found = matches[0];
-
-         if (found == "daily"    || found == "day")       mSecs = 86400 * 1;   // TODO i18n
-    else if (found == "weekdays")                         mSecs = 86400 * 1;   // TODO i18n
-    else if (found == "weekly"   || found == "sennight")  mSecs = 86400 * 7;   // TODO i18n
-    else if (found == "biweekly" || found == "fortnight") mSecs = 86400 * 14;  // TODO i18n
-    else if (found == "monthly")                          mSecs = 86400 * 30;  // TODO i18n
-    else if (found == "bimonthly")                        mSecs = 86400 * 61;  // TODO i18n
-    else if (found == "quarterly")                        mSecs = 86400 * 91;  // TODO i18n
-    else if (found == "semiannual")                       mSecs = 86400 * 183; // TODO i18n
-    else if (found == "yearly"   || found == "annual")    mSecs = 86400 * 365; // TODO i18n
-    else if (found == "biannual" || found == "biyearly")  mSecs = 86400 * 730; // TODO i18n
+    mNegative = true;
+    value = -value;
   }
-
-  // Support -? \d+ \s? s|secs?|m|mins?|h|hrs?|d|days?|wks?|mo|mths?|y|yrs?|-
-  // Note: Does not support a sign character.  That must be external to
-  // Duration.
   else
-  {
-    Nibbler n (lower_input);
-
-    n.skipAll (' ');
     mNegative = false;
-    if (n.skip ('-'))
-      mNegative = true;
 
-    int value;
-    if (n.getUnsignedInt (value))
-    {
-      n.skipAll (' ');
+  std::string units;
+  n.getUntilEOS (units);
 
-           if (n.getLiteral ("yrs")  && n.depleted ()) mSecs = value * 86400 * 365;
-      else if (n.getLiteral ("yr")   && n.depleted ()) mSecs = value * 86400 * 365;
-      else if (n.getLiteral ("y")    && n.depleted ()) mSecs = value * 86400 * 365;
+  // Auto complete against all supported durations.
+  std::vector <std::string> supported;
+  for (unsigned int i = 0; i < NUM_DURATIONS; ++i)
+    supported.push_back (durations[i]);
 
-      else if (n.getLiteral ("qtrs") && n.depleted ()) mSecs = value * 86400 * 91;
-      else if (n.getLiteral ("qtr")  && n.depleted ()) mSecs = value * 86400 * 91;
-      else if (n.getLiteral ("q")    && n.depleted ()) mSecs = value * 86400 * 91;
+  mSecs = 0;
+  std::vector <std::string> matches;
+  if (autoComplete (units, supported, matches) == 1)
+  {
+    std::string match = matches[0];
 
-      else if (n.getLiteral ("mths") && n.depleted ()) mSecs = value * 86400 * 30;
-      else if (n.getLiteral ("mth")  && n.depleted ()) mSecs = value * 86400 * 30;
-      else if (n.getLiteral ("mo")   && n.depleted ()) mSecs = value * 86400 * 30;
+         if (match == "biannual")                         mSecs = value * 86400 * 730;
+    else if (match == "biyearly")                         mSecs = value * 86400 * 730;
 
-      else if (n.getLiteral ("wks")  && n.depleted ()) mSecs = value * 86400 * 7;
-      else if (n.getLiteral ("wk")   && n.depleted ()) mSecs = value * 86400 * 7;
-      else if (n.getLiteral ("w")    && n.depleted ()) mSecs = value * 86400 * 7;
+    else if (match == "yearly")                           mSecs = value * 86400 * 365;
+    else if (match == "annual")                           mSecs = value * 86400 * 365;
+    else if (match == "years")                            mSecs = value * 86400 * 365;
+    else if (match == "yrs")                              mSecs = value * 86400 * 365;
+    else if (match == "y")                                mSecs = value * 86400 * 365;
+    else if (match == "yearly")                           mSecs = value * 86400 * 365;
+    else if (match == "annual")                           mSecs = value * 86400 * 365;
 
-      else if (n.getLiteral ("days") && n.depleted ()) mSecs = value * 86400;
-      else if (n.getLiteral ("day")  && n.depleted ()) mSecs = value * 86400;
-      else if (n.getLiteral ("d")    && n.depleted ()) mSecs = value * 86400;
+    else if (match == "semiannual")                       mSecs = value * 86400 * 183;
 
-      else if (n.getLiteral ("hrs")  && n.depleted ()) mSecs = value * 3600;
-      else if (n.getLiteral ("hr")   && n.depleted ()) mSecs = value * 3600;
-      else if (n.getLiteral ("h")    && n.depleted ()) mSecs = value * 3600;
+    else if (match == "bimonthly")                        mSecs = value * 86400 * 61;
+    else if (match == "quarterly")                        mSecs = value * 86400 * 91;
+    else if (match == "quarters")                         mSecs = value * 86400 * 91;
+    else if (match == "qrtrs")                            mSecs = value * 86400 * 91;
+    else if (match == "qtrs")                             mSecs = value * 86400 * 91;
+    else if (match == "q")                                mSecs = value * 86400 * 91;
 
-      else if (n.getLiteral ("mins") && n.depleted ()) mSecs = value * 60;
-      else if (n.getLiteral ("min")  && n.depleted ()) mSecs = value * 60;
-      else if (n.getLiteral ("m")    && n.depleted ()) mSecs = value * 60;
+    else if (match == "monthly")                          mSecs = value * 86400 * 30;
+    else if (match == "month")                            mSecs = value * 86400 * 30;
+    else if (match == "months")                           mSecs = value * 86400 * 30;
+    else if (match == "mnths")                            mSecs = value * 86400 * 30;
+    else if (match == "mos")                              mSecs = value * 86400 * 30;
+    else if (match == "mo")                               mSecs = value * 86400 * 30;
+    else if (match == "mths")                             mSecs = value * 86400 * 30;
 
-      else if (n.getLiteral ("secs") && n.depleted ()) mSecs = value;
-      else if (n.getLiteral ("sec")  && n.depleted ()) mSecs = value;
-      else if (n.getLiteral ("s")    && n.depleted ()) mSecs = value;
+    else if (match == "biweekly")                         mSecs = value * 86400 * 14;
+    else if (match == "fortnight")                        mSecs = value * 86400 * 14;
 
-      else if (n.getLiteral ("-")    && n.depleted ()) mSecs = 0;
-    }
+    else if (match == "weekly")                           mSecs = value * 86400 * 7;
+    else if (match == "sennight")                         mSecs = value * 86400 * 7;
+    else if (match == "weeks")                            mSecs = value * 86400 * 7;
+    else if (match == "wks")                              mSecs = value * 86400 * 7;
+    else if (match == "w")                                mSecs = value * 86400 * 7;
+
+    else if (match == "daily")                            mSecs = value * 86400 * 1;
+    else if (match == "day")                              mSecs = value * 86400 * 1;
+    else if (match == "weekdays")                         mSecs = value * 86400 * 1;
+    else if (match == "days")                             mSecs = value * 86400 * 1;
+    else if (match == "d")                                mSecs = value * 86400 * 1;
+
+    else if (match == "hours")                            mSecs = value * 3600;
+    else if (match == "hrs")                              mSecs = value * 3600;
+    else if (match == "h")                                mSecs = value * 3600;
+
+    else if (match == "minutes")                          mSecs = value * 60;
+    else if (match == "mins")                             mSecs = value * 60;
+    else if (match == "min")                              mSecs = value * 60;
+    else if (match == "m")                                mSecs = value * 60;
+
+    else if (match == "seconds")                          mSecs = value;
+    else if (match == "secs")                             mSecs = value;
+    else if (match == "sec")                              mSecs = value;
+    else if (match == "s")                                mSecs = value;
+
+    else if (match == "-")                                mSecs = 0;
   }
 
   if (mSecs == 0)
-    throw std::string ("The duration '") + input + "' was not recognized.";  // TODO i18n
+    throw std::string ("The duration '") + input + "' was not recognized.";
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/src/Duration.h b/src/Duration.h
index ac0a0c2e5..cb5e7982a 100644
--- a/src/Duration.h
+++ b/src/Duration.h
@@ -34,7 +34,8 @@ class Duration
 {
 public:
   Duration ();                           // Default constructor
-  Duration (time_t);                     // Default constructor
+  Duration (const Duration&);            // Copy constructor
+  Duration (time_t);                     // Constructor
   Duration (const std::string&);         // Parse
   bool operator< (const Duration&);
   bool operator> (const Duration&);
@@ -47,6 +48,7 @@ public:
   std::string format () const;
   std::string formatCompact () const;
 
+  bool negative () const;
   bool valid (const std::string&) const;
   void parse (const std::string&);
 
diff --git a/src/tests/duration.t.cpp b/src/tests/duration.t.cpp
index 07c88c374..f2bd1efb0 100644
--- a/src/tests/duration.t.cpp
+++ b/src/tests/duration.t.cpp
@@ -506,169 +506,169 @@ int main (int argc, char** argv)
   d = Duration (364*86400), t.is (d.formatCompact (), "11mo", "364*86400 -> 11mo");
   d = Duration (365*86400), t.is (d.formatCompact (), "1.0y", "365*86400 -> 1.0y");
 
-  t.ok (d.valid ("daily"),      "valid duration daily = 1");
-  t.ok (d.valid ("day"),        "valid duration day = 1");
-  t.ok (d.valid ("weekly"),     "valid duration weekly = 7");
-  t.ok (d.valid ("weekdays"),   "valid duration weekdays = 1");
-  t.ok (d.valid ("sennight"),   "valid duration sennight = 7");
-  t.ok (d.valid ("biweekly"),   "valid duration biweekly = 14");
-  t.ok (d.valid ("fortnight"),  "valid duration fortnight = 14");
-  t.ok (d.valid ("monthly"),    "valid duration monthly = 30");
-  t.ok (d.valid ("bimonthly"),  "valid duration bimonthly = 61");
-  t.ok (d.valid ("quarterly"),  "valid duration quarterly = 91");
-  t.ok (d.valid ("annual"),     "valid duration annual = 365");
-  t.ok (d.valid ("yearly"),     "valid duration yearly = 365");
-  t.ok (d.valid ("semiannual"), "valid duration semiannual = 183");
-  t.ok (d.valid ("biannual"),   "valid duration biannual = 730");
-  t.ok (d.valid ("biyearly"),   "valid duration biyearly = 730");
+	t.ok (d.valid ("daily"),      "valid duration daily");
+  t.ok (d.valid ("day"),        "valid duration day");
+  t.ok (d.valid ("weekly"),     "valid duration weekly");
+  t.ok (d.valid ("weekdays"),   "valid duration weekdays");
+  t.ok (d.valid ("sennight"),   "valid duration sennight");
+  t.ok (d.valid ("biweekly"),   "valid duration biweekly");
+  t.ok (d.valid ("fortnight"),  "valid duration fortnight");
+  t.ok (d.valid ("monthly"),    "valid duration monthly");
+  t.ok (d.valid ("bimonthly"),  "valid duration bimonthly");
+  t.ok (d.valid ("quarterly"),  "valid duration quarterly");
+  t.ok (d.valid ("annual"),     "valid duration annual");
+  t.ok (d.valid ("yearly"),     "valid duration yearly");
+  t.ok (d.valid ("semiannual"), "valid duration semiannual");
+  t.ok (d.valid ("biannual"),   "valid duration biannual");
+  t.ok (d.valid ("biyearly"),   "valid duration biyearly");
 
-  t.ok (d.valid ("0 yrs"),      "valid duration 0 yrs = 0");
-  t.ok (d.valid ("0 yr"),       "valid duration 0 yr = 0");
-  t.ok (d.valid ("0y"),         "valid duration 0y = 0");
-  t.ok (d.valid ("1 yrs"),      "valid duration 1 yrs = 365");
-  t.ok (d.valid ("1 yr"),       "valid duration 1 yr = 365");
-  t.ok (d.valid ("1y"),         "valid duration 1y = 365");
-  t.ok (d.valid ("10 yrs"),     "valid duration 10 yrs = 3650");
-  t.ok (d.valid ("10 yr"),      "valid duration 10 yr = 3650");
-  t.ok (d.valid ("10y"),        "valid duration 10y = 3650");
+  t.ok (d.valid ("0 yrs"),      "valid duration 0 yrs");
+  t.ok (d.valid ("0 yr"),       "valid duration 0 yr");
+  t.ok (d.valid ("0y"),         "valid duration 0y");
+  t.ok (d.valid ("1 yrs"),      "valid duration 1 yrs");
+  t.ok (d.valid ("1 yr"),       "valid duration 1 yr");
+  t.ok (d.valid ("1y"),         "valid duration 1y");
+  t.ok (d.valid ("10 yrs"),     "valid duration 10 yrs");
+  t.ok (d.valid ("10 yr"),      "valid duration 10 yr");
+  t.ok (d.valid ("10y"),        "valid duration 10y");
 
-  t.ok (d.valid ("0 qtrs"),     "valid duration 0 qtrs = 0");
-  t.ok (d.valid ("0 qtr"),      "valid duration 0 qtr = 0");
-  t.ok (d.valid ("0q"),         "valid duration 0q = 0");
-  t.ok (d.valid ("1 qtrs"),     "valid duration 1 qtrs = 91");
-  t.ok (d.valid ("1 qtr"),      "valid duration 1 qtr = 91");
-  t.ok (d.valid ("1q"),         "valid duration 1q = 91");
-  t.ok (d.valid ("10 qtrs"),    "valid duration 10 qtrs = 910");
-  t.ok (d.valid ("10 qtr"),     "valid duration 10 qtr = 910");
-  t.ok (d.valid ("10q"),        "valid duration 10q = 910");
+  t.ok (d.valid ("0 qtrs"),     "valid duration 0 qtrs");
+  t.ok (d.valid ("0 qtr"),      "valid duration 0 qtr");
+  t.ok (d.valid ("0q"),         "valid duration 0q");
+  t.ok (d.valid ("1 qtrs"),     "valid duration 1 qtrs");
+  t.ok (d.valid ("1 qtr"),      "valid duration 1 qtr");
+  t.ok (d.valid ("1q"),         "valid duration 1q");
+  t.ok (d.valid ("10 qtrs"),    "valid duration 10 qtrs");
+  t.ok (d.valid ("10 qtr"),     "valid duration 10 qtr");
+  t.ok (d.valid ("10q"),        "valid duration 10q");
 
-  t.ok (d.valid ("0 mths"),     "valid duration 0 mths = 0");
-  t.ok (d.valid ("0 mth"),      "valid duration 0 mth = 0");
-  t.ok (d.valid ("0mo"),        "valid duration 0mo = 0");
-  t.ok (d.valid ("1 mths"),     "valid duration 1 mths = 30");
-  t.ok (d.valid ("1 mth"),      "valid duration 1 mth = 30");
-  t.ok (d.valid ("1mo"),        "valid duration 1mo = 30");
-  t.ok (d.valid ("10 mths"),    "valid duration 10 mths = 300");
-  t.ok (d.valid ("10 mth"),     "valid duration 10 mth = 300");
-  t.ok (d.valid ("10mo"),       "valid duration 10mo = 300");
+  t.ok (d.valid ("0 mnths"),     "valid duration 0 mths");
+  t.ok (d.valid ("0 mnth"),      "valid duration 0 mth");
+  t.ok (d.valid ("0mo"),        "valid duration 0mo");
+  t.ok (d.valid ("1 mnths"),     "valid duration 1 mths");
+  t.ok (d.valid ("1 mth"),      "valid duration 1 mth");
+  t.ok (d.valid ("1mo"),        "valid duration 1mo");
+  t.ok (d.valid ("10 mnths"),    "valid duration 10 mths");
+  t.ok (d.valid ("10 mnth"),     "valid duration 10 mth");
+  t.ok (d.valid ("10mo"),       "valid duration 10mo");
 
-  t.ok (d.valid ("0 wks"),      "valid duration 0 wks = 0");
-  t.ok (d.valid ("0 wk"),       "valid duration 0 wk = 0");
-  t.ok (d.valid ("0w"),         "valid duration 0w = 0");
-  t.ok (d.valid ("1 wks"),      "valid duration 1 wks = 7");
-  t.ok (d.valid ("1 wk"),       "valid duration 1 wk = 7");
-  t.ok (d.valid ("1w"),         "valid duration 1w = 7");
-  t.ok (d.valid ("10 wks"),     "valid duration 10 wks = 70");
-  t.ok (d.valid ("10 wk"),      "valid duration 10 wk = 70");
-  t.ok (d.valid ("10w"),        "valid duration 10w = 70");
+  t.ok (d.valid ("0 wks"),      "valid duration 0 wks");
+  t.ok (d.valid ("0 wk"),       "valid duration 0 wk");
+  t.ok (d.valid ("0w"),         "valid duration 0w");
+  t.ok (d.valid ("1 wks"),      "valid duration 1 wks");
+  t.ok (d.valid ("1 wk"),       "valid duration 1 wk");
+  t.ok (d.valid ("1w"),         "valid duration 1w");
+  t.ok (d.valid ("10 wks"),     "valid duration 10 wks");
+  t.ok (d.valid ("10 wk"),      "valid duration 10 wk");
+  t.ok (d.valid ("10w"),        "valid duration 10w");
 
-  t.ok (d.valid ("0 days"),     "valid duration 0 days = 0");
-  t.ok (d.valid ("0 day"),      "valid duration 0 day = 0");
-  t.ok (d.valid ("0d"),         "valid duration 0d = 0");
-  t.ok (d.valid ("1 days"),     "valid duration 1 days = 1");
-  t.ok (d.valid ("1 day"),      "valid duration 1 day = 1");
-  t.ok (d.valid ("1d"),         "valid duration 1d = 1");
-  t.ok (d.valid ("10 days"),    "valid duration 10 days = 10");
-  t.ok (d.valid ("10 day"),     "valid duration 10 day = 10");
-  t.ok (d.valid ("10d"),        "valid duration 10d = 10");
+  t.ok (d.valid ("0 days"),     "valid duration 0 days");
+  t.ok (d.valid ("0 day"),      "valid duration 0 day");
+  t.ok (d.valid ("0d"),         "valid duration 0d");
+  t.ok (d.valid ("1 days"),     "valid duration 1 days");
+  t.ok (d.valid ("1 day"),      "valid duration 1 day");
+  t.ok (d.valid ("1d"),         "valid duration 1d");
+  t.ok (d.valid ("10 days"),    "valid duration 10 days");
+  t.ok (d.valid ("10 day"),     "valid duration 10 day");
+  t.ok (d.valid ("10d"),        "valid duration 10d");
 
-  t.ok (d.valid ("0 hrs"),      "valid duration 0 hrs = 0");
-  t.ok (d.valid ("0 hr"),       "valid duration 0 hr = 0");
-  t.ok (d.valid ("0h"),         "valid duration 0h = 0");
-  t.ok (d.valid ("1 hrs"),      "valid duration 1 hrs = 0");
-  t.ok (d.valid ("1 hr"),       "valid duration 1 hr = 0");
-  t.ok (d.valid ("1h"),         "valid duration 1h = 0");
-  t.ok (d.valid ("10 hrs"),     "valid duration 10 hrs = 0");
-  t.ok (d.valid ("10 hr"),      "valid duration 10 hr = 0");
-  t.ok (d.valid ("10h"),        "valid duration 10h = 0");
+  t.ok (d.valid ("0 hrs"),      "valid duration 0 hrs");
+  t.ok (d.valid ("0 hr"),       "valid duration 0 hr");
+  t.ok (d.valid ("0h"),         "valid duration 0h");
+  t.ok (d.valid ("1 hrs"),      "valid duration 1 hrs");
+  t.ok (d.valid ("1 hr"),       "valid duration 1 hr");
+  t.ok (d.valid ("1h"),         "valid duration 1h");
+  t.ok (d.valid ("10 hrs"),     "valid duration 10 hrs");
+  t.ok (d.valid ("10 hr"),      "valid duration 10 hr");
+  t.ok (d.valid ("10h"),        "valid duration 10h");
 
-  t.ok (d.valid ("0 mins"),     "valid duration 0 mins = 0");
+  t.ok (d.valid ("0 mins"),     "valid duration 0 mins");
   t.ok (d.valid ("0 min"),      "valid duration 0 min");
-  t.ok (d.valid ("0m"),         "valid duration 0m = 0");
-  t.ok (d.valid ("1 mins"),     "valid duration 1 mins = 0");
-  t.ok (d.valid ("1 min"),      "valid duration 1 min = 0");
-  t.ok (d.valid ("1m"),         "valid duration 1m = 0");
-  t.ok (d.valid ("10 mins"),    "valid duration 10 mins = 0");
-  t.ok (d.valid ("10 min"),     "valid duration 10 min = 0");
-  t.ok (d.valid ("10m"),        "valid duration 10m = 0");
+  t.ok (d.valid ("0m"),         "valid duration 0m");
+  t.ok (d.valid ("1 mins"),     "valid duration 1 mins");
+  t.ok (d.valid ("1 min"),      "valid duration 1 min");
+  t.ok (d.valid ("1m"),         "valid duration 1m");
+  t.ok (d.valid ("10 mins"),    "valid duration 10 mins");
+  t.ok (d.valid ("10 min"),     "valid duration 10 min");
+  t.ok (d.valid ("10m"),        "valid duration 10m");
 
-  t.ok (d.valid ("0 secs"),     "valid duration 0 secs = 0");
-  t.ok (d.valid ("0 sec"),      "valid duration 0 sec = 0");
-  t.ok (d.valid ("0s"),         "valid duration 0s = 0");
-  t.ok (d.valid ("1 secs"),     "valid duration 1 secs = 0");
-  t.ok (d.valid ("1 sec"),      "valid duration 1 sec = 0");
-  t.ok (d.valid ("1s"),         "valid duration 1s = 0");
-  t.ok (d.valid ("10 secs"),    "valid duration 10 secs = 0");
-  t.ok (d.valid ("10 sec"),     "valid duration 10 sec = 0");
-  t.ok (d.valid ("10s"),        "valid duration 10s = 0");
+  t.ok (d.valid ("0 secs"),     "valid duration 0 secs");
+  t.ok (d.valid ("0 sec"),      "valid duration 0 sec");
+  t.ok (d.valid ("0s"),         "valid duration 0s");
+  t.ok (d.valid ("1 secs"),     "valid duration 1 secs");
+  t.ok (d.valid ("1 sec"),      "valid duration 1 sec");
+  t.ok (d.valid ("1s"),         "valid duration 1s");
+  t.ok (d.valid ("10 secs"),    "valid duration 10 secs");
+  t.ok (d.valid ("10 sec"),     "valid duration 10 sec");
+  t.ok (d.valid ("10s"),        "valid duration 10s");
 
   t.notok (d.valid ("woof"),   "valid duration woof = fail");
 
-  t.is (convertDuration ("daily"),         1, "valid duration daily = 1");
-  t.is (convertDuration ("day"),           1, "valid duration day = 1");
-  t.is (convertDuration ("weekly"),        7, "valid duration weekly = 7");
-  t.is (convertDuration ("weekdays"),      1, "valid duration weekdays = 1");
-  t.is (convertDuration ("sennight"),      7, "valid duration sennight = 7");
-  t.is (convertDuration ("biweekly"),     14, "valid duration biweekly = 14");
-  t.is (convertDuration ("fortnight"),    14, "valid duration fortnight = 14");
-  t.is (convertDuration ("monthly"),      30, "valid duration monthly = 30");
-  t.is (convertDuration ("bimonthly"),    61, "valid duration bimonthly = 61");
-  t.is (convertDuration ("quarterly"),    91, "valid duration quarterly = 91");
-  t.is (convertDuration ("annual"),      365, "valid duration annual = 365");
-  t.is (convertDuration ("yearly"),      365, "valid duration yearly = 365");
-  t.is (convertDuration ("semiannual"),  183, "valid duration semiannual = 183");
-  t.is (convertDuration ("biannual"),    730, "valid duration biannual = 730");
-  t.is (convertDuration ("biyearly"),    730, "valid duration biyearly = 730");
+  t.is (convertDuration ("daily"),         1, "valid duration daily");
+  t.is (convertDuration ("day"),           1, "valid duration day");
+  t.is (convertDuration ("weekly"),        7, "valid duration weekly");
+  t.is (convertDuration ("weekdays"),      1, "valid duration weekdays");
+  t.is (convertDuration ("sennight"),      7, "valid duration sennight");
+  t.is (convertDuration ("biweekly"),     14, "valid duration biweekly");
+  t.is (convertDuration ("fortnight"),    14, "valid duration fortnight");
+  t.is (convertDuration ("monthly"),      30, "valid duration monthly");
+  t.is (convertDuration ("bimonthly"),    61, "valid duration bimonthly");
+  t.is (convertDuration ("quarterly"),    91, "valid duration quarterly");
+  t.is (convertDuration ("annual"),      365, "valid duration annual");
+  t.is (convertDuration ("yearly"),      365, "valid duration yearly");
+  t.is (convertDuration ("semiannual"),  183, "valid duration semiannual");
+  t.is (convertDuration ("biannual"),    730, "valid duration biannual");
+  t.is (convertDuration ("biyearly"),    730, "valid duration biyearly");
 
-  t.is (convertDuration ("0 yrs"),         0, "valid duration 0 yrs = 0");
-  t.is (convertDuration ("0 yr"),          0, "valid duration 0 yr = 0");
-  t.is (convertDuration ("0y"),            0, "valid duration 0y = 0");
-  t.is (convertDuration ("1 yrs"),       365, "valid duration 1 yrs = 365");
-  t.is (convertDuration ("1 yr"),        365, "valid duration 1 yr = 365");
-  t.is (convertDuration ("1y"),          365, "valid duration 1y = 365");
-  t.is (convertDuration ("10 yrs"),     3650, "valid duration 10 yrs = 3650");
-  t.is (convertDuration ("10 yr"),      3650, "valid duration 10 yr = 3650");
-  t.is (convertDuration ("10y"),        3650, "valid duration 10y = 3650");
+  t.is (convertDuration ("0 yrs"),         0, "valid duration 0 yrs");
+  t.is (convertDuration ("0 yr"),          0, "valid duration 0 yr");
+  t.is (convertDuration ("0y"),            0, "valid duration 0y");
+  t.is (convertDuration ("1 yrs"),       365, "valid duration 1 yrs");
+  t.is (convertDuration ("1 yr"),        365, "valid duration 1 yr");
+  t.is (convertDuration ("1y"),          365, "valid duration 1y");
+  t.is (convertDuration ("10 yrs"),     3650, "valid duration 10 yrs");
+  t.is (convertDuration ("10 yr"),      3650, "valid duration 10 yr");
+  t.is (convertDuration ("10y"),        3650, "valid duration 10y");
 
-  t.is (convertDuration ("0 qtrs"),        0, "valid duration 0 qtrs = 0");
-  t.is (convertDuration ("0 qtr"),         0, "valid duration 0 qtr = 0");
-  t.is (convertDuration ("0q"),            0, "valid duration 0q = 0");
-  t.is (convertDuration ("1 qtrs"),       91, "valid duration 1 qtrs = 91");
-  t.is (convertDuration ("1 qtr"),        91, "valid duration 1 qtr = 91");
-  t.is (convertDuration ("1q"),           91, "valid duration 1q = 91");
-  t.is (convertDuration ("10 qtrs"),     910, "valid duration 10 qtrs = 910");
-  t.is (convertDuration ("10 qtr"),      910, "valid duration 10 qtr = 910");
-  t.is (convertDuration ("10q"),         910, "valid duration 10q = 910");
+  t.is (convertDuration ("0 qtrs"),        0, "valid duration 0 qtrs");
+  t.is (convertDuration ("0 qtr"),         0, "valid duration 0 qtr");
+  t.is (convertDuration ("0q"),            0, "valid duration 0q");
+  t.is (convertDuration ("1 qtrs"),       91, "valid duration 1 qtrs");
+  t.is (convertDuration ("1 qtr"),        91, "valid duration 1 qtr");
+  t.is (convertDuration ("1q"),           91, "valid duration 1q");
+  t.is (convertDuration ("10 qtrs"),     910, "valid duration 10 qtrs");
+  t.is (convertDuration ("10 qtr"),      910, "valid duration 10 qtr");
+  t.is (convertDuration ("10q"),         910, "valid duration 10q");
 
-  t.is (convertDuration ("0 mths"),        0, "valid duration 0 mths = 0");
-  t.is (convertDuration ("0 mth"),         0, "valid duration 0 mth = 0");
-  t.is (convertDuration ("0mo"),           0, "valid duration 0mo = 0");
-  t.is (convertDuration ("1 mths"),       30, "valid duration 1 mths = 30");
-  t.is (convertDuration ("1 mth"),        30, "valid duration 1 mth = 30");
-  t.is (convertDuration ("1mo"),          30, "valid duration 1mo = 30");
-  t.is (convertDuration ("10 mths"),     300, "valid duration 10 mths = 300");
-  t.is (convertDuration ("10 mth"),      300, "valid duration 10 mth = 300");
-  t.is (convertDuration ("10mo"),        300, "valid duration 10mo = 300");
+  t.is (convertDuration ("0 mths"),        0, "valid duration 0 mths");
+  t.is (convertDuration ("0 mth"),         0, "valid duration 0 mth");
+  t.is (convertDuration ("0mo"),           0, "valid duration 0mo");
+  t.is (convertDuration ("1 mths"),       30, "valid duration 1 mths");
+  t.is (convertDuration ("1 mth"),        30, "valid duration 1 mth");
+  t.is (convertDuration ("1mo"),          30, "valid duration 1mo");
+  t.is (convertDuration ("10 mths"),     300, "valid duration 10 mths");
+  t.is (convertDuration ("10 mth"),      300, "valid duration 10 mth");
+  t.is (convertDuration ("10mo"),        300, "valid duration 10mo");
 
-  t.is (convertDuration ("0 wks"),         0, "valid duration 0 wks = 0");
-  t.is (convertDuration ("0 wk"),          0, "valid duration 0 wk = 0");
-  t.is (convertDuration ("0w"),            0, "valid duration 0w = 0");
-  t.is (convertDuration ("1 wks"),         7, "valid duration 1 wks = 7");
-  t.is (convertDuration ("1 wk"),          7, "valid duration 1 wk = 7");
-  t.is (convertDuration ("1w"),            7, "valid duration 1w = 7");
-  t.is (convertDuration ("10 wks"),       70, "valid duration 10 wks = 70");
-  t.is (convertDuration ("10 wk"),        70, "valid duration 10 wk = 70");
-  t.is (convertDuration ("10w"),          70, "valid duration 10w = 70");
+  t.is (convertDuration ("0 wks"),         0, "valid duration 0 wks");
+  t.is (convertDuration ("0 wk"),          0, "valid duration 0 wk");
+  t.is (convertDuration ("0w"),            0, "valid duration 0w");
+  t.is (convertDuration ("1 wks"),         7, "valid duration 1 wks");
+  t.is (convertDuration ("1 wk"),          7, "valid duration 1 wk");
+  t.is (convertDuration ("1w"),            7, "valid duration 1w");
+  t.is (convertDuration ("10 wks"),       70, "valid duration 10 wks");
+  t.is (convertDuration ("10 wk"),        70, "valid duration 10 wk");
+  t.is (convertDuration ("10w"),          70, "valid duration 10w");
 
-  t.is (convertDuration ("0 days"),        0, "valid duration 0 days = 0");
-  t.is (convertDuration ("0 day"),         0, "valid duration 0 day = 0");
-  t.is (convertDuration ("0d"),            0, "valid duration 0d = 0");
-  t.is (convertDuration ("1 days"),        1, "valid duration 1 days = 1");
-  t.is (convertDuration ("1 day"),         1, "valid duration 1 day = 1");
-  t.is (convertDuration ("1d"),            1, "valid duration 1d = 1");
-  t.is (convertDuration ("10 days"),      10, "valid duration 10 days = 10");
-  t.is (convertDuration ("10 day"),       10, "valid duration 10 day = 10");
-  t.is (convertDuration ("10d"),          10, "valid duration 10d = 10");
+  t.is (convertDuration ("0 days"),        0, "valid duration 0 days");
+  t.is (convertDuration ("0 day"),         0, "valid duration 0 day");
+  t.is (convertDuration ("0d"),            0, "valid duration 0d");
+  t.is (convertDuration ("1 days"),        1, "valid duration 1 days");
+  t.is (convertDuration ("1 day"),         1, "valid duration 1 day");
+  t.is (convertDuration ("1d"),            1, "valid duration 1d");
+  t.is (convertDuration ("10 days"),      10, "valid duration 10 days");
+  t.is (convertDuration ("10 day"),       10, "valid duration 10 day");
+  t.is (convertDuration ("10d"),          10, "valid duration 10d");
 
   try
   {
@@ -700,6 +700,8 @@ int main (int argc, char** argv)
   catch (const std::string& e) { t.diag (e); }
   catch (...) { t.diag ("Unknown error"); }
 
+  // TODO Duration::negative
+
   return 0;
 }
 
diff --git a/src/util.cpp b/src/util.cpp
index 632bb700b..e0dd40ecf 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -195,8 +195,8 @@ int autoComplete (
       }
 
       // Maintain a list of partial matches.
-      if (length <= item->length () &&
-          partial == item->substr (0, length))
+      else if (length <= item->length () &&
+               partial == item->substr (0, length))
         matches.push_back (*item);
     }
   }