diff --git a/tests/phpunit/CiviWP/HookTest.php b/tests/phpunit/CiviWP/HookTest.php
index 4986f08..bffafe5 100644
--- a/tests/phpunit/CiviWP/HookTest.php
+++ b/tests/phpunit/CiviWP/HookTest.php
@@ -11,7 +11,7 @@
    */
   class HookTest extends \PHPUnit\Framework\TestCase implements EndToEndInterface {
 
-    public function testFoo() {
+    public function testFoo(): void {
       add_action('civicrm_fakeAlterableHook', 'onFakeAlterableHook', 10, 2);
 
       $arg1 = 'hello';
diff --git a/tests/phpunit/CiviWP/PhpVersionTest.php b/tests/phpunit/CiviWP/PhpVersionTest.php
index dd5289b..8fb997c 100644
--- a/tests/phpunit/CiviWP/PhpVersionTest.php
+++ b/tests/phpunit/CiviWP/PhpVersionTest.php
@@ -12,7 +12,7 @@ class PhpVersionTest extends \PHPUnit\Framework\TestCase implements EndToEndInte
    *
    * The literal value should be duplicated in the define() to prevent dependency issues.
    */
-  public function testConstantMatch() {
+  public function testConstantMatch(): void {
     $constantFile = $this->getModulePath() . '/civicrm.php';
     $this->assertFileExists($constantFile);
     $content = file_get_contents($constantFile);
diff --git a/tests/phpunit/bootstrap.php b/tests/phpunit/bootstrap.php
index 111952c..7b357ff 100644
--- a/tests/phpunit/bootstrap.php
+++ b/tests/phpunit/bootstrap.php
@@ -4,7 +4,6 @@
 define('CIVICRM_CONTAINER_CACHE', 'never');
 
 ini_set('memory_limit', '2G');
-ini_set('safe_mode', 0);
 // phpcs:disable
 eval(cv('php:boot', 'phpcode'));
 // phpcs:enable
@@ -22,11 +21,11 @@
  * @throws \RuntimeException
  *   If the command terminates abnormally.
  */
-function cv($cmd, $decode = 'json') {
+function cv(string $cmd, $decode = 'json'): string {
   $cmd = 'cv ' . $cmd;
-  $descriptorSpec = array(0 => array("pipe", "r"), 1 => array("pipe", "w"), 2 => STDERR);
+  $descriptorSpec = [0 => ['pipe', 'r'], 1 => ['pipe', 'w'], 2 => STDERR];
   $oldOutput = getenv('CV_OUTPUT');
-  putenv("CV_OUTPUT=json");
+  putenv('CV_OUTPUT=json');
   $process = proc_open($cmd, $descriptorSpec, $pipes, __DIR__);
   putenv("CV_OUTPUT=$oldOutput");
   fclose($pipes[0]);
@@ -41,7 +40,7 @@ function cv($cmd, $decode = 'json') {
 
     case 'phpcode':
       // If the last output is /*PHPCODE*/, then we managed to complete execution.
-      if (substr(trim($result), 0, 12) !== "/*BEGINPHP*/" || substr(trim($result), -10) !== "/*ENDPHP*/") {
+      if (substr(trim($result), 0, 12) !== '/*BEGINPHP*/' || substr(trim($result), -10) !== '/*ENDPHP*/') {
         throw new \RuntimeException("Command failed ($cmd):\n$result");
       }
       return $result;