Drop Carbon requirement

composer.json

@@ -9,9 +9,6 @@
             "email": "pdt256@gmail.com"
         }
     ],
-    "require": {
-        "nesbot/carbon": "~1.0"
-    },
     "require-dev": {
         "phpunit/phpunit": "4.0.*"
     },

src/Fedex/Rate.php

@@ -1,7 +1,7 @@
 <?php
 namespace pdt256\Shipping\Fedex;
 
-use Carbon\Carbon;
+use DateTime;
 use pdt256\Shipping;
 use pdt256\Shipping\Arr;
 use pdt256\Shipping\Quote;
@@ -230,7 +230,7 @@ class Rate extends RateAdapter
 				->setCost((int) $cost * 100)
 				->setTransitTime($transit_time);
 			if ($delivery_ts) {
-				$quote->setDeliveryEstimate(new Carbon($delivery_ts));
+				$quote->setDeliveryEstimate(new DateTime($delivery_ts));
 			}
 
 			$this->rates[] = $quote;

src/Quote.php

@@ -1,6 +1,6 @@
 <?php namespace pdt256\Shipping;
 
-use Carbon\Carbon;
+use DateTime;
 
 class Quote
 {
@@ -112,10 +112,10 @@ class Quote
     }
 
     /**
-     * @param Carbon $estimate
+     * @param DateTime $estimate
      * @return $this
      */
-    public function setDeliveryEstimate(Carbon $estimate)
+    public function setDeliveryEstimate(DateTime $estimate)
     {
         $this->delivery_ts = $estimate;
         return $this;

tests/ShipTest.php

@@ -1,5 +1,4 @@
 <?php
-use Carbon\Carbon;
 use pdt256\Shipping\Package;
 use pdt256\Shipping\Quote;
 use pdt256\Shipping\Ship;
@@ -201,7 +200,7 @@ class ShipTest extends PHPUnit_Framework_TestCase
 			->setCode('FEDEX_EXPRESS_SAVER')
 			->setName('Fedex Express Saver')
 			->setCost(2900)
-			->setDeliveryEstimate(new Carbon('2014-09-30T20:00:00'))
+			->setDeliveryEstimate(new DateTime('2014-09-30T20:00:00'))
 			->setTransitTime(null);
 
 		$secondday = new Quote;
@@ -210,7 +209,7 @@ class ShipTest extends PHPUnit_Framework_TestCase
 			->setCode('FEDEX_2_DAY')
 			->setName('Fedex 2 Day')
 			->setCost(4000)
-			->setDeliveryEstimate(new Carbon('2014-09-29T20:00:00'))
+			->setDeliveryEstimate(new DateTime('2014-09-29T20:00:00'))
 			->setTransitTime(null);
 
 		$overnight = new Quote;
@@ -219,7 +218,7 @@ class ShipTest extends PHPUnit_Framework_TestCase
 			->setCode('STANDARD_OVERNIGHT')
 			->setName('Standard Overnight')
 			->setCost(7800)
-			->setDeliveryEstimate(new Carbon('2014-09-26T20:00:00'))
+			->setDeliveryEstimate(new DateTime('2014-09-26T20:00:00'))
 			->setTransitTime(null);
 
 		$expected_result = [$ground, $express, $secondday, $overnight];
@@ -253,14 +252,14 @@ class ShipTest extends PHPUnit_Framework_TestCase
 		$fedex_two_day->setCode('FEDEX_2_DAY')
 			->setName('Fedex 2 Day')
 			->setCost(4000)
-			->setDeliveryEstimate(new Carbon('2014-09-29T20:00:00'))
+			->setDeliveryEstimate(new DateTime('2014-09-29T20:00:00'))
 			->setCarrier('fedex');
 
 		$overnight = new Quote;
 		$overnight->setCode('STANDARD_OVERNIGHT')
 			->setName('Standard Overnight')
 			->setCost(7800)
-			->setDeliveryEstimate(new Carbon('2014-09-26T20:00:00'))
+			->setDeliveryEstimate(new DateTime('2014-09-26T20:00:00'))
 			->setCarrier('fedex');
 
 		$this->assertEquals([