Fix Duration => string conversion for milliseconds

src/ExecutionTimer/Duration.php

@@ -29,10 +29,19 @@ class Duration {
      */
     public function __toString () {
         return $this->getDays()->asRelativeWhole() . ' '
-               . str_pad($this->getHours()->asRelativeWhole(), mb_strlen($this->getHours()->getUnitMax()), '0', STR_PAD_LEFT) . ':'
+               . self::showUnit($this->getHours()) . ':'
-               . str_pad($this->getMinutes()->asRelativeWhole(), mb_strlen($this->getMinutes()->getUnitMax()), '0', STR_PAD_LEFT) . ':'
+               . self::showUnit($this->getMinutes()) . ':'
-               . str_pad($this->getSeconds()->asRelativeWhole(), mb_strlen($this->getSeconds()->getUnitMax()), '0', STR_PAD_LEFT) . '.'
+               . self::showUnit($this->getSeconds()) . '.'
-               . str_pad($this->getMilliseconds()->asRelativeWhole(), mb_strlen($this->getMilliseconds()->getUnitMax()), '0', STR_PAD_LEFT);
+               . self::showUnit($this->getMilliseconds());
+    }
+    private static function showUnit (DurationUnit $durationUnit) {
+        $max = $durationUnit->getUnitMax();
+        $length = mb_strlen($max);
+        if (preg_match('/^1[0]*$/', $max)) {
+            $length -= 1;
+        }
+
+        return str_pad($durationUnit->asRelativeWhole(), $length, '0', STR_PAD_LEFT);
     }
     /**
      * Convert duration to user friendly string