diff --git a/.gitattributes b/.gitattributes
index f2f51dd..64ab6e0 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -3,4 +3,5 @@
 /.travis.yml export-ignore
 /examples export-ignore
 /phpunit.xml.dist export-ignore
+/phpunit.xml.legacy export-ignore
 /tests export-ignore
diff --git a/.travis.yml b/.travis.yml
index cc82aaf..a2498b1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -29,8 +29,9 @@ jobs:
     - os: osx
 
 install:
-  - composer install --no-interaction
+  - composer install
 
 script:
-  - vendor/bin/phpunit --coverage-text
+  - if [[ "$TRAVIS_PHP_VERSION" > "7.2" ]]; then vendor/bin/phpunit --coverage-text; fi
+  - if [[ "$TRAVIS_PHP_VERSION" < "7.3" ]]; then vendor/bin/phpunit --coverage-text -c phpunit.xml.legacy; fi
   - time php examples/91-benchmark-throughput.php
diff --git a/composer.json b/composer.json
index d376084..aada0be 100644
--- a/composer.json
+++ b/composer.json
@@ -31,7 +31,7 @@
         "evenement/evenement": "^3.0 || ^2.0 || ^1.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.0 || ^5.7 || ^4.8.35",
+        "phpunit/phpunit": "^9.3 || ^5.7 || ^4.8.35",
         "clue/stream-filter": "~1.2"
     },
     "autoload": {
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 0e947b8..fa88e7e 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,15 +1,19 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
-<phpunit bootstrap="vendor/autoload.php" colors="true">
+<!-- PHPUnit configuration file with new format for PHPUnit 9.3+ -->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
+         bootstrap="vendor/autoload.php"
+         colors="true"
+         cacheResult="false">
     <testsuites>
         <testsuite name="React Test Suite">
             <directory>./tests/</directory>
         </testsuite>
     </testsuites>
-
-    <filter>
-        <whitelist>
+    <coverage>
+        <include>
             <directory>./src/</directory>
-        </whitelist>
-    </filter>
+        </include>
+    </coverage>
 </phpunit>
diff --git a/phpunit.xml.legacy b/phpunit.xml.legacy
new file mode 100644
index 0000000..fbb43e8
--- /dev/null
+++ b/phpunit.xml.legacy
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!-- PHPUnit configuration file with old format for PHPUnit 9.2 or older -->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/4.8/phpunit.xsd"
+         bootstrap="vendor/autoload.php"
+         colors="true">
+    <testsuites>
+        <testsuite name="React Test Suite">
+            <directory>./tests/</directory>
+        </testsuite>
+    </testsuites>
+    <filter>
+        <whitelist>
+            <directory>./src/</directory>
+        </whitelist>
+    </filter>
+</phpunit>
diff --git a/tests/TestCase.php b/tests/TestCase.php
index 2b0928f..7bef2f5 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -6,16 +6,6 @@
 
 class TestCase extends BaseTestCase
 {
-    protected function expectCallableExactly($amount)
-    {
-        $mock = $this->createCallableMock();
-        $mock
-            ->expects($this->exactly($amount))
-            ->method('__invoke');
-
-        return $mock;
-    }
-
     protected function expectCallableOnce()
     {
         $mock = $this->createCallableMock();
@@ -61,7 +51,7 @@ protected function createCallableMock()
     public function setExpectedException($exception, $exceptionMessage = '', $exceptionCode = null)
     {
         if (method_exists($this, 'expectException')) {
-            // PHPUnit 5+
+            // PHPUnit 5.2+
             $this->expectException($exception);
             if ($exceptionMessage !== '') {
                 $this->expectExceptionMessage($exceptionMessage);
@@ -70,7 +60,7 @@ public function setExpectedException($exception, $exceptionMessage = '', $except
                 $this->expectExceptionCode($exceptionCode);
             }
         } else {
-            // legacy PHPUnit 4
+            // legacy PHPUnit 4 - PHPUnit 5.1
             parent::setExpectedException($exception, $exceptionMessage, $exceptionCode);
         }
     }
diff --git a/tests/UtilTest.php b/tests/UtilTest.php
index 3d113ab..f12baad 100644
--- a/tests/UtilTest.php
+++ b/tests/UtilTest.php
@@ -265,9 +265,4 @@ private function createLoopMock()
     {
         return $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
     }
-
-    private function notEqualTo($value)
-    {
-        return new \PHPUnit_Framework_Constraint_Not($value);
-    }
 }
diff --git a/tests/WritableStreamResourceTest.php b/tests/WritableResourceStreamTest.php
similarity index 94%
rename from tests/WritableStreamResourceTest.php
rename to tests/WritableResourceStreamTest.php
index 3192abd..7b36418 100644
--- a/tests/WritableStreamResourceTest.php
+++ b/tests/WritableResourceStreamTest.php
@@ -461,33 +461,6 @@ public function testWritingToClosedWritableResourceStreamShouldNotWriteToStream(
         $this->assertSame('', $filterBuffer);
     }
 
-    /**
-     * @covers React\Stream\WritableResourceStream::handleWrite
-     */
-    public function testErrorWhenStreamResourceIsInvalid()
-    {
-        $stream = fopen('php://temp', 'r+');
-        $loop = $this->createWriteableLoopMock();
-
-        $error = null;
-
-        $buffer = new WritableResourceStream($stream, $loop);
-        $buffer->on('error', function ($message) use (&$error) {
-            $error = $message;
-        });
-
-        // invalidate stream resource
-        fclose($stream);
-
-        $buffer->write('Attempting to write to bad stream');
-
-        $this->assertInstanceOf('Exception', $error);
-
-        // the error messages differ between PHP versions, let's just check substrings
-        $this->assertContainsString('Unable to write to stream: ', $error->getMessage());
-        $this->assertContainsStringIgnoringCase(' Not a valid stream resource', $error->getMessage());
-    }
-
     public function testWritingToClosedStream()
     {
         if ('Darwin' === PHP_OS) {