this should cover everything

src/Carbon/Carbon.php

@@ -85,7 +85,8 @@ class Carbon extends DateTime
 	    '+',
 	    '-',
 	    'first',
-	    'last'
+	    'last',
+	    'ago'
     );
 
    /**
@@ -732,13 +733,12 @@ public static function hasTestNow()
 	/**
 	 * Determine if there is a relative keyword in the time string, this is to
 	 * create dates relative to now for test instances. e.g.: next tuesday
-	 * TODO: add support for 'ago' which would typically be at the end of a phrase
 	 *
 	 * @return boolean true if there is a keyword, otherwise false
 	 */
 	public static function hasRelativeKeywords($time) {
 		foreach(self::$relativeKeywords as $keyword) {
-			if (stripos(trim($time), $keyword) === 0) {
+			if (stripos(trim($time), $keyword) !== false) {
 				return true;
 			}
 		}

tests/TestingAidsTest.php

@@ -61,9 +61,13 @@ public function testParseWithTestValueSet()
 
    public function testParseRelativeWithTestValueSet() 
    {
-	  $notNow = Carbon::parse('2013-09-01');
+	  $notNow = Carbon::parse('2013-09-01 05:15:05');
 	  Carbon::setTestNow($notNow);
 
+	  $this->assertEquals('2013-09-01 05:10:05', Carbon::parse('5 minutes ago')->toDateTimeString());
+
+	  $this->assertEquals('2013-08-25 05:15:05', Carbon::parse('1 week ago')->toDateTimeString());
+
 	  $this->assertEquals('2013-09-02', Carbon::parse('tomorrow')->toDateString());
 	  $this->assertEquals('2013-08-31', Carbon::parse('yesterday')->toDateString());