diff --git a/composer.json b/composer.json
index 705ac57..3f31f0a 100644
--- a/composer.json
+++ b/composer.json
@@ -28,7 +28,7 @@
     "minimum-stability": "stable",
     "require": {
         "php": ">=5.5.0",
-        "phpunit/phpunit": "^4.8 || ^5.7",
+        "phpunit/phpunit": "^4.8.35 || ^5.7",
         "phpunit/php-code-coverage": "^2.2 || ^4.0 || ^5.2",
         "squizlabs/php_codesniffer": "^2.8",
         "symfony/console": "^3.2",
diff --git a/tests/Phug/DevTool/ApplicationTest.php b/tests/Phug/DevTool/ApplicationTest.php
index 3ff08ad..74bf207 100644
--- a/tests/Phug/DevTool/ApplicationTest.php
+++ b/tests/Phug/DevTool/ApplicationTest.php
@@ -2,6 +2,7 @@
 
 namespace Phug\Test\DevTool;
 
+use PHPUnit\Framework\TestCase;
 use Phug\DevTool\Application;
 use Symfony\Component\Console\Application as ConsoleApplication;
 use Symfony\Component\Console\Input\StringInput;
@@ -12,7 +13,7 @@
  *
  * @coversDefaultClass \Phug\DevTool\Application
  */
-class ApplicationTest extends \PHPUnit_Framework_TestCase
+class ApplicationTest extends TestCase
 {
     /**
      * @covers ::__construct
diff --git a/tests/Phug/DevTool/Command/CheckCommandTest.php b/tests/Phug/DevTool/Command/CheckCommandTest.php
index 38f72c8..88d0dad 100644
--- a/tests/Phug/DevTool/Command/CheckCommandTest.php
+++ b/tests/Phug/DevTool/Command/CheckCommandTest.php
@@ -2,6 +2,7 @@
 
 namespace Phug\Test\DevTool;
 
+use PHPUnit\Framework\TestCase;
 use Phug\DevTool\Application;
 use Phug\DevTool\Command\CheckCommand;
 use Symfony\Component\Console\Input\StringInput;
@@ -12,7 +13,7 @@
  *
  * @coversDefaultClass \Phug\DevTool\Command\CheckCommand
  */
-class CheckCommandTest extends \PHPUnit_Framework_TestCase
+class CheckCommandTest extends TestCase
 {
     /**
      * @covers ::configure
diff --git a/tests/Phug/DevTool/Command/CodeStyleCheckCommandTest.php b/tests/Phug/DevTool/Command/CodeStyleCheckCommandTest.php
index 6908708..2fdb28b 100644
--- a/tests/Phug/DevTool/Command/CodeStyleCheckCommandTest.php
+++ b/tests/Phug/DevTool/Command/CodeStyleCheckCommandTest.php
@@ -2,6 +2,7 @@
 
 namespace Phug\Test\DevTool;
 
+use PHPUnit\Framework\TestCase;
 use Phug\DevTool\Application;
 use Phug\DevTool\Command\CodeStyleCheckCommand;
 use Symfony\Component\Console\Input\StringInput;
@@ -12,7 +13,7 @@
  *
  * @coversDefaultClass \Phug\DevTool\Command\CodeStyleCheckCommand
  */
-class CodeStyleCheckCommandTest extends \PHPUnit_Framework_TestCase
+class CodeStyleCheckCommandTest extends TestCase
 {
     /**
      * @covers ::configure
diff --git a/tests/Phug/DevTool/Command/CodeStyleFixCommandTest.php b/tests/Phug/DevTool/Command/CodeStyleFixCommandTest.php
index e10a6c1..54fd85b 100644
--- a/tests/Phug/DevTool/Command/CodeStyleFixCommandTest.php
+++ b/tests/Phug/DevTool/Command/CodeStyleFixCommandTest.php
@@ -2,6 +2,7 @@
 
 namespace Phug\Test\DevTool;
 
+use PHPUnit\Framework\TestCase;
 use Phug\DevTool\Command\CodeStyleFixCommand;
 
 /**
@@ -9,7 +10,7 @@
  *
  * @coversDefaultClass \Phug\DevTool\Command\CodeStyleFixCommand
  */
-class CodeStyleFixCommandTest extends \PHPUnit_Framework_TestCase
+class CodeStyleFixCommandTest extends TestCase
 {
     /**
      * @covers ::configure
diff --git a/tests/Phug/DevTool/Command/CoverageCheckCommandTest.php b/tests/Phug/DevTool/Command/CoverageCheckCommandTest.php
index 8670733..e3ba5b4 100644
--- a/tests/Phug/DevTool/Command/CoverageCheckCommandTest.php
+++ b/tests/Phug/DevTool/Command/CoverageCheckCommandTest.php
@@ -2,6 +2,7 @@
 
 namespace Phug\Test\DevTool;
 
+use PHPUnit\Framework\TestCase;
 use Phug\DevTool\Command\CoverageCheckCommand;
 
 /**
@@ -9,7 +10,7 @@
  *
  * @coversDefaultClass \Phug\DevTool\Command\CoverageCheckCommand
  */
-class CoverageCheckCommandTest extends \PHPUnit_Framework_TestCase
+class CoverageCheckCommandTest extends TestCase
 {
     /**
      * @covers ::configure
diff --git a/tests/Phug/DevTool/Command/CoverageReportCommandTest.php b/tests/Phug/DevTool/Command/CoverageReportCommandTest.php
index 5188807..dae1dfa 100644
--- a/tests/Phug/DevTool/Command/CoverageReportCommandTest.php
+++ b/tests/Phug/DevTool/Command/CoverageReportCommandTest.php
@@ -2,6 +2,7 @@
 
 namespace Phug\Test\DevTool;
 
+use PHPUnit\Framework\TestCase;
 use Phug\DevTool\Command\CoverageReportCommand;
 
 /**
@@ -9,7 +10,7 @@
  *
  * @coversDefaultClass \Phug\DevTool\Command\CoverageReportCommand
  */
-class CoverageReportCommandTest extends \PHPUnit_Framework_TestCase
+class CoverageReportCommandTest extends TestCase
 {
     /**
      * @covers ::configure
diff --git a/tests/Phug/DevTool/Command/InstallCommandTest.php b/tests/Phug/DevTool/Command/InstallCommandTest.php
index 59ed2e8..6961f26 100644
--- a/tests/Phug/DevTool/Command/InstallCommandTest.php
+++ b/tests/Phug/DevTool/Command/InstallCommandTest.php
@@ -2,6 +2,7 @@
 
 namespace Phug\Test\DevTool;
 
+use PHPUnit\Framework\TestCase;
 use Phug\DevTool\Command\InstallCommand;
 
 /**
@@ -9,7 +10,7 @@
  *
  * @coversDefaultClass \Phug\DevTool\Command\InstallCommand
  */
-class InstallCommandTest extends \PHPUnit_Framework_TestCase
+class InstallCommandTest extends TestCase
 {
     /**
      * @covers ::configure
diff --git a/tests/Phug/DevTool/Command/UnitTestsRunCommandTest.php b/tests/Phug/DevTool/Command/UnitTestsRunCommandTest.php
index 50e69ee..c5d9b7b 100644
--- a/tests/Phug/DevTool/Command/UnitTestsRunCommandTest.php
+++ b/tests/Phug/DevTool/Command/UnitTestsRunCommandTest.php
@@ -2,6 +2,7 @@
 
 namespace Phug\Test\DevTool;
 
+use PHPUnit\Framework\TestCase;
 use Phug\DevTool\Application;
 use Phug\DevTool\Command\UnitTestsRunCommand;
 use Symfony\Component\Console\Input\StringInput;
@@ -12,7 +13,7 @@
  *
  * @coversDefaultClass \Phug\DevTool\Command\UnitTestsRunCommand
  */
-class UnitTestsRunCommandTest extends \PHPUnit_Framework_TestCase
+class UnitTestsRunCommandTest extends TestCase
 {
     private static function remove($entity)
     {