diff --git a/.travis.yml b/.travis.yml
index ca3d1a2..1c6086a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,6 +5,9 @@ php:
   - 7.0
   - 7.1
   - 7.2
+  - 7.3
+  - 7.4
+  - 8.0
 
 sudo: false
 
diff --git a/composer.json b/composer.json
index fa75da5..7b6409f 100644
--- a/composer.json
+++ b/composer.json
@@ -11,10 +11,10 @@
         }
     ],
     "require": {
-        "php": "^5.6 || ^7.0"
+        "php": ">=5.6"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.8 || ^5.5"
+        "phpunit/phpunit": "^4.8 || ^5.5 || >=6.0"
     },
     "autoload": {
         "psr-4": {
diff --git a/tests/CalendarExportTest.php b/tests/CalendarExportTest.php
index 7158531..ac30471 100644
--- a/tests/CalendarExportTest.php
+++ b/tests/CalendarExportTest.php
@@ -23,8 +23,9 @@
 use Jsvrcek\ICS\CalendarExport;
 use Jsvrcek\ICS\Model\Calendar;
 use Jsvrcek\ICS\Model\CalendarEvent;
+use PHPUnit\Framework\TestCase;
 
-class CalendarExportTest extends \PHPUnit_Framework_TestCase
+class CalendarExportTest extends TestCase
 {
     /**
      * @covers Jsvrcek\ICS\CalendarExport::getStream
diff --git a/tests/CalendarStreamTest.php b/tests/CalendarStreamTest.php
index aee2e53..117f0ee 100644
--- a/tests/CalendarStreamTest.php
+++ b/tests/CalendarStreamTest.php
@@ -4,8 +4,9 @@
 
 use Jsvrcek\ICS\CalendarStream;
 use Jsvrcek\ICS\Constants;
+use PHPUnit\Framework\TestCase;
 
-class CalendarStreamTest extends \PHPUnit_Framework_TestCase
+class CalendarStreamTest extends TestCase
 {
     public function testGetStream()
     {
diff --git a/tests/Model/CalendarEventTest.php b/tests/Model/CalendarEventTest.php
index b7e3212..38d93e7 100644
--- a/tests/Model/CalendarEventTest.php
+++ b/tests/Model/CalendarEventTest.php
@@ -4,74 +4,59 @@
 
 use Jsvrcek\ICS\Model\CalendarEvent;
 use Jsvrcek\ICS\Exception\CalendarEventException;
+use PHPUnit\Framework\TestCase;
 
 /**
  * Generated by PHPUnit_SkeletonGenerator on 2013-10-20 at 12:03:54.
  */
-class CalendarEventTest extends \PHPUnit_Framework_TestCase
+class CalendarEventTest extends TestCase
 {
-    /**
-     * @var CalendarEvent
-     */
-    protected $object;
-
-    /**
-     * Sets up the fixture, for example, opens a network connection.
-     * This method is called before a test is executed.
-     * @return CalendarEvent
-     */
-    protected function setUp()
-    {
-        $this->object = new CalendarEvent;
-    }
-
-    /**
-     * Tears down the fixture, for example, closes a network connection.
-     * This method is called after a test is executed.
-     */
-    protected function tearDown()
-    {
-    }
-
     /**
      * @covers Jsvrcek\ICS\Model\CalendarEvent::setStart
      */
     public function testSetStart()
     {
         $start = new \DateTime();
+        $object = new CalendarEvent;
         
-        $this->object->setStart($start);
+        $object->setStart($start);
         
         // test start
-        $this->assertEquals($start, $this->object->getStart());
+        $this->assertEquals($start, $object->getStart());
         
         //test default end
-        $this->assertEquals($start->add(\DateInterval::createFromDateString('30 minutes')), $this->object->getEnd());
+        $this->assertEquals($start->add(\DateInterval::createFromDateString('30 minutes')), $object->getEnd());
     }
 
     /**
      * @covers Jsvrcek\ICS\Model\CalendarEvent::setEnd
-     * @expectedException Jsvrcek\ICS\Exception\CalendarEventException
-     * @expectedExceptionMessage End DateTime must be greater than Start DateTime
      */
     public function testSetEndDateEarlierThanStart()
     {
+        $this->expectException(CalendarEventException::class);
+        $this->expectExceptionMessage('End DateTime must be greater than Start DateTime');
+
+        $object = new CalendarEvent;
+
         $start = new \DateTime('now');
         $end = new \DateTime('yesterday');
         
-        $this->object->setStart($start);
-        $this->object->setEnd($end);
+        $object->setStart($start);
+        $object->setEnd($end);
     }
 
     /**
      * @covers Jsvrcek\ICS\Model\CalendarEvent::setEnd
-     * @expectedException Jsvrcek\ICS\Exception\CalendarEventException
-     * @expectedExceptionMessage You must set the Start time before setting the End Time of a CalendarEvent
      */
     public function testSetEndWithoutStart()
     {
+        $this->expectException(CalendarEventException::class);
+        $this->expectExceptionMessage('You must set the Start time before setting the End Time of a CalendarEvent');
+
+        $object = new CalendarEvent;
+
         $end = new \DateTime('yesterday');
         
-        $this->object->setEnd($end);
+        $object->setEnd($end);
     }
 }
diff --git a/tests/Model/CalendarTest.php b/tests/Model/CalendarTest.php
index 4fa227f..2230d5a 100644
--- a/tests/Model/CalendarTest.php
+++ b/tests/Model/CalendarTest.php
@@ -3,11 +3,12 @@
 namespace Jsvrcek\ICS\Tests\Model;
 
 use Jsvrcek\ICS\Model\Calendar;
+use PHPUnit\Framework\TestCase;
 
 /**
  * Generated by PHPUnit_SkeletonGenerator on 2013-10-20 at 15:24:14.
  */
-class CalendarTest extends \PHPUnit_Framework_TestCase
+class CalendarTest extends TestCase
 {
     /**
      * @covers Jsvrcek\ICS\Model\Calendar::__construct
diff --git a/tests/Model/Recurrence/RecurrenceRuleTest.php b/tests/Model/Recurrence/RecurrenceRuleTest.php
index faaef6d..c288b1a 100644
--- a/tests/Model/Recurrence/RecurrenceRuleTest.php
+++ b/tests/Model/Recurrence/RecurrenceRuleTest.php
@@ -8,38 +8,18 @@
 
 use Jsvrcek\ICS\Utility\Formatter;
 use Jsvrcek\ICS\Model\Recurrence\RecurrenceRule;
+use PHPUnit\Framework\TestCase;
 
-class RecurrenceRuleTest extends \PHPUnit_Framework_TestCase
+class RecurrenceRuleTest extends TestCase
 {
-    /**
-     * @var RecurrenceRule
-     */
-    protected $object;
-
-    /**
-     * Sets up the fixture, for example, opens a network connection.
-     * This method is called before a test is executed.
-     * @return Rule
-     */
-    protected function setUp()
-    {
-        $this->object = new RecurrenceRule(new Formatter());
-    }
-
-    /**
-     * Tears down the fixture, for example, closes a network connection.
-     * This method is called after a test is executed.
-     */
-    protected function tearDown()
-    {
-    }
-
     /**
      * @covers Jsvrcek\ICS\Model\Recurrence\RecurrentRule::__toString()
      */
     public function testToString()
     {
-        $this->object
+        $object = new RecurrenceRule(new Formatter());
+
+        $object
             ->setFrequency(new Frequency(Frequency::YEARLY))
             ->setInterval(2)
             ->setCount(10)
@@ -50,12 +30,12 @@ public function testToString()
         
         $expected = 'RRULE:FREQ=YEARLY;INTERVAL=2;UNTIL=20500101T000000Z;COUNT=10;BYDAY=10MO,-10TU';
         
-        $this->assertEquals($expected, $this->object->__toString());
+        $this->assertEquals($expected, $object->__toString());
 
         //get a new object, test byMonth
-        $this->setUp();
+        $object = new RecurrenceRule(new Formatter());
 
-        $this->object
+        $object
             ->setFrequency(new Frequency(Frequency::WEEKLY))
             ->setInterval(1)
             ->addByMonth(2)
@@ -65,7 +45,7 @@ public function testToString()
 
         $expected = 'RRULE:FREQ=WEEKLY;INTERVAL=1;BYMONTH=2,3,4';
         
-        $this->assertEquals($expected, $this->object->__toString());
+        $this->assertEquals($expected, $object->__toString());
     }
     
     /**
@@ -74,25 +54,24 @@ public function testToString()
      */
     public function testParse()
     {
-        //reset instance
-        $this->setUp();
+        $object = new RecurrenceRule(new Formatter());
         
         $rRuleString = 'RRULE:FREQ=YEARLY;INTERVAL=2';
-        $this->object->parse($rRuleString);
-        $this->assertEquals($rRuleString, $this->object->__toString());
+        $object->parse($rRuleString);
+        $this->assertEquals($rRuleString, $object->__toString());
         
         $rRuleString = 'RRULE:FREQ=WEEKLY;INTERVAL=4';
-        $this->object->parse($rRuleString);
-        $this->assertEquals($rRuleString, $this->object->__toString());
+        $object->parse($rRuleString);
+        $this->assertEquals($rRuleString, $object->__toString());
         
         $rRuleString = 'RRULE:FREQ=WEEKLY;INTERVAL=4;UNTIL=20500101T000000Z';
-        $this->object->parse($rRuleString);
-        $this->assertEquals($rRuleString, $this->object->__toString());
+        $object->parse($rRuleString);
+        $this->assertEquals($rRuleString, $object->__toString());
         
         /*
         $rRuleString = 'RRULE:FREQ=YEARLY;INTERVAL=2;COUNT=10;BYDAY=10MO,-10TU';
-        $this->object->parse($rRuleString);
-        $this->assertEquals($rRuleString, $this->object->__toString());
+        $object->parse($rRuleString);
+        $this->assertEquals($rRuleString, $object->__toString());
         */
     }
 }
diff --git a/tests/Model/Relationship/AttendeeTest.php b/tests/Model/Relationship/AttendeeTest.php
index ae077be..22cd146 100644
--- a/tests/Model/Relationship/AttendeeTest.php
+++ b/tests/Model/Relationship/AttendeeTest.php
@@ -4,38 +4,18 @@
 
 use Jsvrcek\ICS\Utility\Formatter;
 use Jsvrcek\ICS\Model\Relationship\Attendee;
+use PHPUnit\Framework\TestCase;
 
-class AttendeeTest extends \PHPUnit_Framework_TestCase
+class AttendeeTest extends TestCase
 {
-    /**
-     * @var Attendee
-     */
-    protected $object;
-
-    /**
-     * Sets up the fixture, for example, opens a network connection.
-     * This method is called before a test is executed.
-     * @return Attendee
-     */
-    protected function setUp()
-    {
-        $this->object = new Attendee(new Formatter());
-    }
-
-    /**
-     * Tears down the fixture, for example, closes a network connection.
-     * This method is called after a test is executed.
-     */
-    protected function tearDown()
-    {
-    }
-
     /**
      * @covers Jsvrcek\ICS\Model\Attendee::__toString()
      */
     public function testToString()
     {
-        $this->object
+        $object = new Attendee(new Formatter());
+
+        $object
             ->setValue('joe-smith@example.com')
             ->setName('Joe Smith')
             ->setCalendarUserType('INDIVIDUAL')
@@ -51,6 +31,6 @@ public function testToString()
         
         $expected = 'ATTENDEE;CUTYPE=INDIVIDUAL;MEMBER="mailto:list@example.com";ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED;RSVP=TRUE;DELEGATED-TO="mailto:sue@example.com","mailto:jane@example.com";DELEGATED-FROM="mailto:mary@example.com";SENT-BY="jack@example.com";CN=Joe Smith;LANGUAGE=en:mailto:joe-smith@example.com';
         
-        $this->assertEquals($expected, $this->object->__toString());
+        $this->assertEquals($expected, $object->__toString());
     }
 }
diff --git a/tests/Model/Relationship/OrganizerTest.php b/tests/Model/Relationship/OrganizerTest.php
index f030595..bd4eb9e 100644
--- a/tests/Model/Relationship/OrganizerTest.php
+++ b/tests/Model/Relationship/OrganizerTest.php
@@ -4,38 +4,18 @@
 
 use Jsvrcek\ICS\Utility\Formatter;
 use Jsvrcek\ICS\Model\Relationship\Organizer;
+use PHPUnit\Framework\TestCase;
 
-class OrganizerTest extends \PHPUnit_Framework_TestCase
+class OrganizerTest extends TestCase
 {
-    /**
-     * @var Organizer
-     */
-    protected $object;
-
-    /**
-     * Sets up the fixture, for example, opens a network connection.
-     * This method is called before a test is executed.
-     * @return Organizer
-     */
-    protected function setUp()
-    {
-        $this->object = new Organizer(new Formatter());
-    }
-
-    /**
-     * Tears down the fixture, for example, closes a network connection.
-     * This method is called after a test is executed.
-     */
-    protected function tearDown()
-    {
-    }
-
     /**
      * @covers Jsvrcek\ICS\Model\Organizer::__toString()
      */
     public function testToString()
     {
-        $this->object
+        $object = new Organizer(new Formatter());
+
+        $object
             ->setValue('leonardo@example.it')
             ->setName('Leonardo Da Vinci')
             ->setLanguage('it')
@@ -44,6 +24,6 @@ public function testToString()
         
         $expected = 'ORGANIZER;SENT-BY="piero@example.com";CN=Leonardo Da Vinci;DIR="http://en.wikipedia.org/wiki/Leonardo_da_Vinci";LANGUAGE=it:mailto:leonardo@example.it';
         
-        $this->assertEquals($expected, $this->object->__toString());
+        $this->assertEquals($expected, $object->__toString());
     }
 }
diff --git a/tests/Utility/FormatterTest.php b/tests/Utility/FormatterTest.php
index 122cc76..3d77e5f 100644
--- a/tests/Utility/FormatterTest.php
+++ b/tests/Utility/FormatterTest.php
@@ -4,8 +4,9 @@
 
 use Jsvrcek\ICS\Model\Description\Conference;
 use Jsvrcek\ICS\Utility\Formatter;
+use PHPUnit\Framework\TestCase;
 
-class FormatterTest extends \PHPUnit_Framework_TestCase
+class FormatterTest extends TestCase
 {
     /**
      * @covers Jsvrcek\ICS\Formatter::getFormattedDateTime
diff --git a/tests/Utility/ProviderTest.php b/tests/Utility/ProviderTest.php
index b2780b2..d6a7a4d 100644
--- a/tests/Utility/ProviderTest.php
+++ b/tests/Utility/ProviderTest.php
@@ -3,8 +3,9 @@
 namespace Jsvrcek\ICS\Tests\Utility;
 
 use Jsvrcek\ICS\Utility\Provider;
+use PHPUnit\Framework\TestCase;
 
-class ProviderTest extends \PHPUnit_Framework_TestCase
+class ProviderTest extends TestCase
 {
     /**
      * @covers Jsvrcek\ICS\Utility\Provider::first