diff --git a/composer.json b/composer.json
index 8dc753c..7025bc3 100644
--- a/composer.json
+++ b/composer.json
@@ -51,7 +51,6 @@
     },
     "require-dev": {
         "phpunit/phpunit": "^9.6.23",
-        "amphp/phpunit-util": "^3",
         "amphp/php-cs-fixer-config": "^2.1.0",
         "psalm/phar": "6.16.1"
     }
diff --git a/test/AcmeClientTest.php b/test/AcmeClientTest.php
index 6909dd2..7570c32 100644
--- a/test/AcmeClientTest.php
+++ b/test/AcmeClientTest.php
@@ -13,15 +13,15 @@
 use Amp\Http\Client\HttpClientBuilder;
 use Amp\Http\Client\Request;
 use Amp\Http\Client\Response;
-use Amp\PHPUnit\AsyncTestCase;
 use Amp\Socket\ClientTlsContext;
 use Amp\Socket\ConnectContext;
 use Kelunik\Acme\Crypto\RsaKeyGenerator;
+use PHPUnit\Framework\TestCase;
 use ReflectionClass;
 use function Amp\Dns\createDefaultResolver;
 use function Amp\Dns\dnsResolver;
 
-final class AcmeClientTest extends AsyncTestCase
+final class AcmeClientTest extends TestCase
 {
     /** @var UnlimitedConnectionPool */
     private $httpPool;
diff --git a/test/AcmeServiceTest.php b/test/AcmeServiceTest.php
index 567c134..ce74281 100644
--- a/test/AcmeServiceTest.php
+++ b/test/AcmeServiceTest.php
@@ -5,15 +5,15 @@
 use Amp\Http\Client\Connection\DefaultConnectionFactory;
 use Amp\Http\Client\Connection\UnlimitedConnectionPool;
 use Amp\Http\Client\HttpClientBuilder;
-use Amp\PHPUnit\AsyncTestCase;
 use Amp\Socket\ClientTlsContext;
 use Amp\Socket\ConnectContext;
 use Kelunik\Acme\Crypto\RsaKeyGenerator;
 use Kelunik\Acme\Csr\OpensslCsrGenerator;
 use Kelunik\Acme\Protocol\Authorization;
 use Kelunik\Acme\Protocol\Challenge;
+use PHPUnit\Framework\TestCase;
 
-final class AcmeServiceTest extends AsyncTestCase
+final class AcmeServiceTest extends TestCase
 {
     private AcmeService $service;
 
diff --git a/test/ConnectTest.php b/test/ConnectTest.php
index b354337..27b3761 100644
--- a/test/ConnectTest.php
+++ b/test/ConnectTest.php
@@ -2,12 +2,12 @@
 
 namespace Kelunik\Acme;
 
-use Amp\PHPUnit\AsyncTestCase;
 use Amp\Socket\ClientTlsContext;
 use Amp\Socket\ConnectContext;
+use PHPUnit\Framework\TestCase;
 use function Amp\Socket\connect;
 
-final class ConnectTest extends AsyncTestCase
+final class ConnectTest extends TestCase
 {
     /**
      * Test that TLS connections to the ACME server succeed.
diff --git a/test/Dns01VerificationTest.php b/test/Dns01VerificationTest.php
index 984706d..d8d1047 100644
--- a/test/Dns01VerificationTest.php
+++ b/test/Dns01VerificationTest.php
@@ -6,10 +6,10 @@
 use Amp\Dns\DnsRecord;
 use Amp\Dns\DnsResolver;
 use Amp\Dns\MissingDnsRecordException;
-use Amp\PHPUnit\AsyncTestCase;
 use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
 
-final class Dns01VerificationTest extends AsyncTestCase
+final class Dns01VerificationTest extends TestCase
 {
     /** @var DnsResolver&MockObject */
     private DnsResolver $resolver;
diff --git a/test/Http01VerificationTest.php b/test/Http01VerificationTest.php
index 7621504..9ad9ff9 100644
--- a/test/Http01VerificationTest.php
+++ b/test/Http01VerificationTest.php
@@ -4,9 +4,9 @@
 
 use Amp\Http\Client\HttpClientBuilder;
 use Amp\Http\Client\Request;
-use Amp\PHPUnit\AsyncTestCase;
+use PHPUnit\Framework\TestCase;
 
-final class Http01VerificationTest extends AsyncTestCase
+final class Http01VerificationTest extends TestCase
 {
     /**
      * @var Verifiers\Http01
diff --git a/test/OpensslCsrGeneratorTest.php b/test/OpensslCsrGeneratorTest.php
index d7053b4..9682d38 100644
--- a/test/OpensslCsrGeneratorTest.php
+++ b/test/OpensslCsrGeneratorTest.php
@@ -2,14 +2,14 @@
 
 namespace Kelunik\Acme;
 
-use Amp\PHPUnit\AsyncTestCase;
 use Kelunik\Acme\Crypto\KeyGenerator;
 use Kelunik\Acme\Crypto\PrivateKey;
 use Kelunik\Acme\Crypto\RsaKeyGenerator;
 use Kelunik\Acme\Csr\CsrGenerator;
 use Kelunik\Acme\Csr\OpensslCsrGenerator;
+use PHPUnit\Framework\TestCase;
 
-final class OpensslCsrGeneratorTest extends AsyncTestCase
+final class OpensslCsrGeneratorTest extends TestCase
 {
     private KeyGenerator $keyGenerator;
     private CsrGenerator $csrGenerator;