diff --git a/composer.json b/composer.json
index f3b9424..cd85370 100644
--- a/composer.json
+++ b/composer.json
@@ -8,7 +8,8 @@
         "google/gax": "^1.1"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.8|^5.0",
+        "phpunit/phpunit": "^4.8|^5.0|^8.0",
+        "yoast/phpunit-polyfills": "^1.0",
         "google/cloud-core": "^1.39",
         "phpdocumentor/reflection": "^3.0"
     },
diff --git a/tests/Unit/BootstrapTest.php b/tests/Unit/BootstrapTest.php
index e9eb34c..2e9ef77 100644
--- a/tests/Unit/BootstrapTest.php
+++ b/tests/Unit/BootstrapTest.php
@@ -22,7 +22,7 @@
 use Google\Cloud\ErrorReporting\MockValues;
 use Google\Cloud\Logging\PsrLogger;
 use Prophecy\Argument;
-use PHPUnit\Framework\TestCase;
+use Yoast\PHPUnitPolyfills\TestCases\TestCase;
 
 //@codingStandardsIgnoreStart
 require_once __DIR__ . '/fakeGlobalFunctions.php';
@@ -37,7 +37,7 @@ class BootstrapTest extends TestCase
     private $psrBatchLogger;
     private $metadataProvider;
 
-    public function setUp()
+    public function set_up()
     {
         $this->psrBatchLogger = $this->prophesize(PsrLogger::class);
     }