diff --git a/composer.json b/composer.json
index 6024d5d..a8c52ab 100644
--- a/composer.json
+++ b/composer.json
@@ -23,7 +23,7 @@
         "doctrine/annotations": "1.*"
     },
     "require-dev": {
-        "phpunit/phpunit": "^7 | ^8 | ^9"
+        "phpunit/phpunit": "^7 | ^8.5.52 | ^9.6.33"
     },
     "autoload": {
         "psr-0": {
diff --git a/src/Yandex/Allure/Adapter/Model/TestSuite.php b/src/Yandex/Allure/Adapter/Model/TestSuite.php
index 6100d14..7f7fbf5 100644
--- a/src/Yandex/Allure/Adapter/Model/TestSuite.php
+++ b/src/Yandex/Allure/Adapter/Model/TestSuite.php
@@ -210,7 +210,7 @@ public function setDescription(Description $description)
      */
     public function addTestCase(TestCase $testCase)
     {
-        $this->testCases[$testCase->getName()] = $testCase;
+        $this->testCases[$testCase->getName() ?? ''] = $testCase;
     }
 
     /**
@@ -220,7 +220,7 @@ public function addTestCase(TestCase $testCase)
      */
     public function getTestCase($name)
     {
-        return $this->testCases[$name];
+        return $this->testCases[$name ?? ''];
     }
 
     /**