diff --git a/composer.json b/composer.json
index 8e31f95..1b9ade3 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
         "symbiote/silverstripe-queuedjobs": "^4"
     },
     "require-dev": {
-        "sminnee/phpunit": "^5.7",
+        "phpunit/phpunit": "^9",
         "squizlabs/php_codesniffer": "^3.0"
     },
     "extra": {
diff --git a/src/Jobs/GenerateCSVJob.php b/src/Jobs/GenerateCSVJob.php
index 9cbb9dd..7b758aa 100644
--- a/src/Jobs/GenerateCSVJob.php
+++ b/src/Jobs/GenerateCSVJob.php
@@ -387,7 +387,7 @@ protected function outputRows(GridField $gridField, $columns, $start, $count)
         }
     }
 
-    public function setup()
+    public function setUp()
     {
         parent::setup();
         $gridField = $this->getGridField();
diff --git a/tests/GenerateCSVJobTest.php b/tests/GenerateCSVJobTest.php
index 507f83f..c5dd060 100644
--- a/tests/GenerateCSVJobTest.php
+++ b/tests/GenerateCSVJobTest.php
@@ -19,7 +19,7 @@ class GenerateCSVJobTest extends SapphireTest
 
     protected static $extra_controllers = [GenerateCSVJobTestController::class];
 
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
 
@@ -32,7 +32,7 @@ protected function setUp()
 
     protected $paths = [];
 
-    protected function tearDown()
+    protected function tearDown(): void
     {
         foreach ($this->paths as $path) {
             Filesystem::removeFolder(dirname($path));
@@ -57,7 +57,7 @@ public function testGenerateExport()
         $this->paths[] = $path; // Mark for cleanup later
 
         // Test that the job runs
-        $this->assertFileNotExists($path);
+        $this->assertFileDoesNotExist($path);
         $job->setup();
         $job->process();
         $job->afterComplete();
@@ -72,8 +72,8 @@ public function testGenerateExport()
         ];
         $actual = file_get_contents($path);
         // Note: strtolower() is for case insensitive comparison, since field label casing changed in SS 4.3
-        $this->assertContains('title,content,"publish on"', strtolower($actual));
-        $this->assertContains(implode("\r\n", $expected), $actual);
+        $this->assertStringContainsString('title,content,"publish on"', strtolower($actual));
+        $this->assertStringContainsString(implode("\r\n", $expected), $actual);
     }
 
     public function testGenerateExportOverMultipleSteps()
@@ -96,7 +96,7 @@ public function testGenerateExportOverMultipleSteps()
         $this->paths[] = $path; // Mark for cleanup later
 
         // Test that the job runs
-        $this->assertFileNotExists($path);
+        $this->assertFileDoesNotExist($path);
         $count = 0;
         while (!$job->jobFinished()) {
             ++$count;
@@ -120,8 +120,8 @@ public function testGenerateExportOverMultipleSteps()
         ];
         $actual = file_get_contents($path);
         // Note: strtolower() is for case insensitive comparison, since field label casing changed in SS 4.3
-        $this->assertContains('title,content,"publish on"', strtolower($actual));
-        $this->assertContains(implode("\r\n", $expected), $actual);
+        $this->assertStringContainsString('title,content,"publish on"', strtolower($actual));
+        $this->assertStringContainsString(implode("\r\n", $expected), $actual);
     }
 
     /**