diff --git a/composer.json b/composer.json
index 7731be6..054e629 100644
--- a/composer.json
+++ b/composer.json
@@ -29,7 +29,7 @@
         "php-amqplib/php-amqplib": "^2.6"
     },
     "require-dev": {
-        "phpunit/phpunit": "^6.0",
+        "phpunit/phpunit": "^8.0",
         "scrutinizer/ocular": "^1.2",
         "squizlabs/php_codesniffer": "^2.6"
     },
diff --git a/tests/ConsumerTest.php b/tests/ConsumerTest.php
index 8dbe1c0..82f8f80 100644
--- a/tests/ConsumerTest.php
+++ b/tests/ConsumerTest.php
@@ -25,7 +25,7 @@ class ConsumerTest extends BaseTest
      */
     public $mockChannel;
 
-    public function setUp()
+    protected function setUp(): void
     {
         $this->mockConnection = $this->getMockConnection();
         $this->mockChannel = $this->getMockChannel();
diff --git a/tests/ProducerTest.php b/tests/ProducerTest.php
index ec49f79..14d252b 100644
--- a/tests/ProducerTest.php
+++ b/tests/ProducerTest.php
@@ -25,7 +25,7 @@ class ProducerTest extends BaseTest
      */
     private $mockChannel;
 
-    public function setUp()
+    protected function setUp(): void
     {
         $this->mockConnection = $this->getMockConnection();
         $this->mockChannel = $this->getMockChannel();
diff --git a/tests/RpcClientTest.php b/tests/RpcClientTest.php
index eab595d..e7a01d9 100644
--- a/tests/RpcClientTest.php
+++ b/tests/RpcClientTest.php
@@ -17,7 +17,7 @@ class RpcClientTest extends BaseTest
      */
     private $mockChannel;
 
-    public function setUp()
+    protected function setUp(): void
     {
         $mockConnection = $this->getMockConnection();
         $this->mockChannel = $this->getMockChannel();
diff --git a/tests/RpcServerTest.php b/tests/RpcServerTest.php
index b3f9d44..4f12b25 100644
--- a/tests/RpcServerTest.php
+++ b/tests/RpcServerTest.php
@@ -23,7 +23,7 @@ class RpcServerTest extends BaseTest
      */
     private $server;
 
-    public function setUp()
+    protected function setUp(): void
     {
         $this->mockConnection = $this->getMockConnection();