diff --git a/tests/Codec/OrderedTimeCodecTest.php b/tests/Codec/OrderedTimeCodecTest.php
index 33dae91..9cc4a43 100644
--- a/tests/Codec/OrderedTimeCodecTest.php
+++ b/tests/Codec/OrderedTimeCodecTest.php
@@ -29,8 +29,8 @@ class OrderedTimeCodecTest extends TestCase
     protected function setUp()
     {
         parent::setUp();
-        $this->builder = $this->getMockBuilder('Ramsey\Uuid\Builder\UuidBuilderInterface')->getMock();
-        $this->uuid = $this->getMockBuilder('Ramsey\Uuid\UuidInterface')->getMock();
+        $this->builder = $this->getMockBuilder(UuidBuilderInterface::class)->getMock();
+        $this->uuid = $this->getMockBuilder(UuidInterface::class)->getMock();
         $this->fields = ['time_low' => '58e0a7d7',
             'time_mid' => 'eebc',
             'time_hi_and_version' => '11d8',
diff --git a/tests/UuidFactoryTest.php b/tests/UuidFactoryTest.php
index cf6dcc6..f722d0e 100644
--- a/tests/UuidFactoryTest.php
+++ b/tests/UuidFactoryTest.php
@@ -4,6 +4,12 @@ namespace Ramsey\Uuid\Test;
 
 use Ramsey\Uuid\FeatureSet;
 use Ramsey\Uuid\UuidFactory;
+use Ramsey\Uuid\Codec\CodecInterface;
+use Ramsey\Uuid\Generator\RandomGeneratorInterface;
+use Ramsey\Uuid\Provider\NodeProviderInterface;
+use Ramsey\Uuid\Generator\TimeGeneratorInterface;
+use Ramsey\Uuid\Converter\NumberConverterInterface;
+use Ramsey\Uuid\Builder\UuidBuilderInterface;
 
 class UuidFactoryTest extends TestCase
 {
@@ -38,12 +44,12 @@ class UuidFactoryTest extends TestCase
 
     public function testGettersReturnValueFromFeatureSet()
     {
-        $codec = $this->getMockBuilder('Ramsey\Uuid\Codec\CodecInterface')->getMock();
-        $nodeProvider = $this->getMockBuilder('Ramsey\Uuid\Provider\NodeProviderInterface')->getMock();
-        $randomGenerator = $this->getMockBuilder('Ramsey\Uuid\Generator\RandomGeneratorInterface')->getMock();
-        $timeGenerator = $this->getMockBuilder('Ramsey\Uuid\Generator\TimeGeneratorInterface')->getMock();
+        $codec = $this->getMockBuilder(CodecInterface::class)->getMock();
+        $nodeProvider = $this->getMockBuilder(NodeProviderInterface::class)->getMock();
+        $randomGenerator = $this->getMockBuilder(RandomGeneratorInterface::class)->getMock();
+        $timeGenerator = $this->getMockBuilder(TimeGeneratorInterface::class)->getMock();
 
-        $featureSet = $this->getMockBuilder('Ramsey\Uuid\FeatureSet')->getMock();
+        $featureSet = $this->getMockBuilder(FeatureSet::class)->getMock();
         $featureSet->method('getCodec')->willReturn($codec);
         $featureSet->method('getNodeProvider')->willReturn($nodeProvider);
         $featureSet->method('getRandomGenerator')->willReturn($randomGenerator);
@@ -79,19 +85,19 @@ class UuidFactoryTest extends TestCase
     {
         $uuidFactory = new UuidFactory();
 
-        $codec = $this->getMockBuilder('Ramsey\Uuid\Codec\CodecInterface')->getMock();
+        $codec = $this->getMockBuilder(CodecInterface::class)->getMock();
         $uuidFactory->setCodec($codec);
         $this->assertEquals($codec, $uuidFactory->getCodec());
 
-        $timeGenerator = $this->getMockBuilder('Ramsey\Uuid\Generator\TimeGeneratorInterface')->getMock();
+        $timeGenerator = $this->getMockBuilder(TimeGeneratorInterface::class)->getMock();
         $uuidFactory->setTimeGenerator($timeGenerator);
         $this->assertEquals($timeGenerator, $uuidFactory->getTimeGenerator());
 
-        $numberConverter = $this->getMockBuilder('Ramsey\Uuid\Converter\NumberConverterInterface')->getMock();
+        $numberConverter = $this->getMockBuilder(NumberConverterInterface::class)->getMock();
         $uuidFactory->setNumberConverter($numberConverter);
         $this->assertEquals($numberConverter, $uuidFactory->getNumberConverter());
 
-        $uuidBuilder = $this->getMockBuilder('Ramsey\Uuid\Builder\UuidBuilderInterface')->getMock();
+        $uuidBuilder = $this->getMockBuilder(UuidBuilderInterface::class)->getMock();
         $uuidFactory->setUuidBuilder($uuidBuilder);
         $this->assertEquals($uuidBuilder, $uuidFactory->getUuidBuilder());
     }
diff --git a/tests/UuidTest.php b/tests/UuidTest.php
index 6ea5414..5304b78 100644
--- a/tests/UuidTest.php
+++ b/tests/UuidTest.php
@@ -4,10 +4,13 @@ namespace Ramsey\Uuid\Test;
 
 use Ramsey\Uuid\Codec\TimestampFirstCombCodec;
 use Ramsey\Uuid\Codec\TimestampLastCombCodec;
+use Ramsey\Uuid\Converter\Number\DegradedNumberConverter;
+use Ramsey\Uuid\DegradedUuid;
 use Ramsey\Uuid\FeatureSet;
 use Ramsey\Uuid\Provider\Time\FixedTimeProvider;
 use Ramsey\Uuid\Generator\CombGenerator;
 use Ramsey\Uuid\Generator\RandomGeneratorFactory;
+use Ramsey\Uuid\Generator\RandomGeneratorInterface;
 use Ramsey\Uuid\Uuid;
 use Ramsey\Uuid\UuidFactory;
 use stdClass;
@@ -226,8 +229,8 @@ class UuidTest extends TestCase
 
         $uuid = Uuid::fromString('ff6f8cb0-c57d-11e1-9b21-0800200c9a66');
 
-        $this->assertInstanceOf('Ramsey\Uuid\DegradedUuid', $uuid);
-        $this->assertInstanceOf('Ramsey\Uuid\Converter\Number\DegradedNumberConverter', $uuid->getNumberConverter());
+        $this->assertInstanceOf(DegradedUuid::class, $uuid);
+        $this->assertInstanceOf(DegradedNumberConverter::class, $uuid->getNumberConverter());
 
         $date = $uuid->getDateTime();
     }
@@ -809,7 +812,7 @@ class UuidTest extends TestCase
     public function testUuid4()
     {
         $uuid = Uuid::uuid4();
-        $this->assertInstanceOf('Ramsey\Uuid\Uuid', $uuid);
+        $this->assertInstanceOf(Uuid::class, $uuid);
         $this->assertEquals(2, $uuid->getVariant());
         $this->assertEquals(4, $uuid->getVersion());
     }
@@ -820,7 +823,7 @@ class UuidTest extends TestCase
      */
     public function testUuid4TimestampLastComb()
     {
-        $mock = $this->getMockBuilder('Ramsey\Uuid\Generator\RandomGeneratorInterface')->getMock();
+        $mock = $this->getMockBuilder(RandomGeneratorInterface::class)->getMock();
         $mock->expects($this->any())
             ->method('generate')
             ->willReturnCallback(function ($length) {
@@ -852,7 +855,7 @@ class UuidTest extends TestCase
      */
     public function testUuid4TimestampFirstComb()
     {
-        $mock = $this->getMockBuilder('Ramsey\Uuid\Generator\RandomGeneratorInterface')->getMock();
+        $mock = $this->getMockBuilder(RandomGeneratorInterface::class)->getMock();
         $mock->expects($this->any())
             ->method('generate')
             ->willReturnCallback(function ($length) {
@@ -1444,8 +1447,8 @@ class UuidTest extends TestCase
      */
     public function testUsingNilAsValidUuid()
     {
-        $this->assertInstanceOf('Ramsey\Uuid\Uuid', Uuid::uuid3(Uuid::NIL, 'randomtext'));
-        $this->assertInstanceOf('Ramsey\Uuid\Uuid', Uuid::uuid5(Uuid::NIL, 'randomtext'));
+        $this->assertInstanceOf(Uuid::class, Uuid::uuid3(Uuid::NIL, 'randomtext'));
+        $this->assertInstanceOf(Uuid::class, Uuid::uuid5(Uuid::NIL, 'randomtext'));
     }
 
     /**