diff --git a/.travis.yml b/.travis.yml
index dc3b5a7..9495663 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,7 +3,7 @@ language: php
 # lock distro so future defaults will not break the build
 dist: trusty
 
-matrix:
+jobs:
   include:
     - php: 5.3
       dist: precise
@@ -17,7 +17,7 @@ matrix:
     - php: 7.4
 
 install:
-  - composer install --no-interaction
+  - composer install
 
 script:
   - vendor/bin/phpunit --coverage-text
diff --git a/composer.json b/composer.json
index 22a582e..d1f6ebb 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,7 @@
     "require-dev": {
         "clue/hexdump": "~0.2.0",
         "react/event-loop": "^1.0 || ^0.5 || ^0.4 || ^0.3",
-        "phpunit/phpunit": "^7.0 || ^6.0 || ^5.0 || ^4.8.35"
+        "phpunit/phpunit": "^9.0 || ^5.7 || ^4.8.35"
     },
     "autoload": {
         "psr-4": { "Clue\\React\\Tar\\": "src/" }
diff --git a/tests/DecoderTest.php b/tests/DecoderTest.php
index e315aab..6b83112 100644
--- a/tests/DecoderTest.php
+++ b/tests/DecoderTest.php
@@ -10,7 +10,10 @@ class DecoderTest extends TestCase
 {
     private $decoder;
 
-    public function setUp()
+    /**
+     * @before
+     */
+    public function setUpDecoder()
     {
         $this->decoder = new Decoder();
     }
diff --git a/tests/FunctionalDecoderTest.php b/tests/FunctionalDecoderTest.php
index 652d472..0e06352 100644
--- a/tests/FunctionalDecoderTest.php
+++ b/tests/FunctionalDecoderTest.php
@@ -10,7 +10,10 @@ class FunctionDecoderTest extends TestCase
 {
     private $decoder;
 
-    public function setUp()
+    /**
+     * @before
+     */
+    public function setUpDecoderAndLoop()
     {
         $this->decoder = new Decoder();
         $this->loop = Factory::create();
diff --git a/tests/TestCase.php b/tests/TestCase.php
index 3cde635..7ccc770 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -7,9 +7,7 @@ class TestCase extends \PHPUnit\Framework\TestCase
     protected function expectCallableOnce()
     {
         $mock = $this->createCallableMock();
-        $mock
-            ->expects($this->once())
-            ->method('__invoke');
+        $mock->expects($this->once())->method('__invoke');
 
         return $mock;
     }
@@ -17,10 +15,7 @@ protected function expectCallableOnce()
     protected function expectCallableOnceWith($value)
     {
         $mock = $this->createCallableMock();
-        $mock
-            ->expects($this->once())
-            ->method('__invoke')
-            ->with($value);
+        $mock->expects($this->once())->method('__invoke')->with($value);
 
         return $mock;
     }
@@ -28,15 +23,19 @@ protected function expectCallableOnceWith($value)
     protected function expectCallableNever()
     {
         $mock = $this->createCallableMock();
-        $mock
-            ->expects($this->never())
-            ->method('__invoke');
+        $mock->expects($this->never())->method('__invoke');
 
         return $mock;
     }
 
     protected function createCallableMock()
     {
-        return $this->getMockBuilder('stdClass')->setMethods(array('__invoke'))->getMock();
+        if (method_exists('PHPUnit\Framework\MockObject\MockBuilder', 'addMethods')) {
+            // PHPUnit 9+
+            return $this->getMockBuilder('stdClass')->addMethods(array('__invoke'))->getMock();
+        } else {
+            // legacy PHPUnit 4 - PHPUnit 8
+            return $this->getMockBuilder('stdClass')->setMethods(array('__invoke'))->getMock();
+        }
     }
 }