diff --git a/composer.json b/composer.json
index e358e68d..435d8ab0 100644
--- a/composer.json
+++ b/composer.json
@@ -21,8 +21,8 @@
         }
     ],
     "require": {
-        "php": ">=5.6",
-        "sminnee/phpunit": "^5.7",
+        "php": ">=7.3",
+        "phpunit/phpunit": "^9.5",
         "squizlabs/php_codesniffer": "^3",
         "behat/behat": "^3.2",
         "behat/mink": "^1.7",
@@ -30,7 +30,7 @@
         "silverstripe/mink-facebook-web-driver": "^1",
         "symfony/dom-crawler": "^3 || ^4",
         "silverstripe/testsession": "^2.2",
-        "silverstripe/framework": "^4",
+        "silverstripe/framework": "^4.10",
         "symfony/finder": "^3.2 || ^4"
     },
     "autoload": {
diff --git a/docs/tutorial.md b/docs/tutorial.md
index 6bebc76c..fee890d4 100644
--- a/docs/tutorial.md
+++ b/docs/tutorial.md
@@ -246,7 +246,7 @@ not exactly one record found in the relation, and hence fail that step for Behat
 public function thereShouldBeAnAbuseReportForWithReason($id, $reason)
 {
     $page = $this->fixtureFactory->get('Page', $id);
-    assertEquals(1, $page->PageAbuseReports()->filter('Reason', $reason)->Count());
+    Assert::assertEquals(1, $page->PageAbuseReports()->filter('Reason', $reason)->Count());
 }
 ```
 
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index b00a4eac..a313a562 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,6 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit bootstrap="vendor/silverstripe/framework/tests/bootstrap.php" colors="true">
-    <testsuite name="Default">
-        <directory>tests/php</directory>
-    </testsuite>
+    <testsuites>
+        <testsuite name="Default">
+            <directory>tests/php</directory>
+        </testsuite>
+    </testsuites>
 </phpunit>
diff --git a/src/Context/BasicContext.php b/src/Context/BasicContext.php
index 640f99ec..df671ac6 100644
--- a/src/Context/BasicContext.php
+++ b/src/Context/BasicContext.php
@@ -17,6 +17,7 @@
 use Facebook\WebDriver\WebDriverAlert;
 use Facebook\WebDriver\WebDriverExpectedCondition;
 use InvalidArgumentException;
+use PHPUnit\Framework\Assert;
 use SilverStripe\Assets\File;
 use SilverStripe\Assets\Filesystem;
 use SilverStripe\BehatExtension\Utility\StepHelper;
@@ -366,7 +367,7 @@ public function takeScreenshot(StepScope $event)
     public function stepPageCantBeFound()
     {
         $page = $this->getSession()->getPage();
-        assertTrue(
+        Assert::assertTrue(
             // Content from ErrorPage default record
             $page->hasContent('Page not found')
             // Generic ModelAsController message
@@ -425,9 +426,9 @@ public function iShouldSeeAButton($negative, $text)
     {
         $button = $this->findNamedButton($text);
         if (trim($negative)) {
-            assertNull($button, sprintf('%s button found', $text));
+            Assert::assertNull($button, sprintf('%s button found', $text));
         } else {
-            assertNotNull($button, sprintf('%s button not found', $text));
+            Assert::assertNotNull($button, sprintf('%s button not found', $text));
         }
     }
 
@@ -438,7 +439,7 @@ public function iShouldSeeAButton($negative, $text)
     public function stepIPressTheButton($text)
     {
         $button = $this->findNamedButton($text);
-        assertNotNull($button, "{$text} button not found");
+        Assert::assertNotNull($button, "{$text} button not found");
         $button->click();
     }
 
@@ -456,7 +457,7 @@ public function stepIPressTheButtons($text)
             }
         }
 
-        assertNotNull($button, "{$text} button not found");
+        Assert::assertNotNull($button, "{$text} button not found");
         $button->click();
     }
 
@@ -495,7 +496,7 @@ public function iClickOnTheElement($selector)
     {
         $page = $this->getMainContext()->getSession()->getPage();
         $element = $page->find('css', $selector);
-        assertNotNull($element, sprintf('Element %s not found', $selector));
+        Assert::assertNotNull($element, sprintf('Element %s not found', $selector));
         $element->click();
     }
 
@@ -525,9 +526,9 @@ public function iClickInTheElement($clickType, $text, $selector)
         );
         $page = $this->getSession()->getPage();
         $parentElement = $page->find('css', $selector);
-        assertNotNull($parentElement, sprintf('"%s" element not found', $selector));
+        Assert::assertNotNull($parentElement, sprintf('"%s" element not found', $selector));
         $element = $parentElement->find('xpath', sprintf('//*[count(*)=0 and contains(.,"%s")]', $text));
-        assertNotNull($element, sprintf('"%s" not found', $text));
+        Assert::assertNotNull($element, sprintf('"%s" not found', $text));
         $clickTypeFn = $clickTypeMap[$clickType];
         $element->$clickTypeFn();
     }
@@ -569,7 +570,7 @@ public function iClickInTheElementDismissingTheDialog($clickType, $text, $select
     public function iSeeTheDialogText($expected)
     {
         $text = $this->getExpectedAlert()->getText();
-        assertContains($expected, $text);
+        Assert::assertStringContainsString($expected, $text);
     }
 
     /**
@@ -841,13 +842,13 @@ public function stepFieldShouldBeDisabled($name, $type, $negate)
             ));
         }
 
-        assertNotNull($element, sprintf("Element '%s' not found", $name));
+        Assert::assertNotNull($element, sprintf("Element '%s' not found", $name));
 
         $disabledAttribute = $element->getAttribute('disabled');
         if (trim($negate)) {
-            assertNull($disabledAttribute, sprintf("Failed asserting element '%s' is not disabled", $name));
+            Assert::assertNull($disabledAttribute, sprintf("Failed asserting element '%s' is not disabled", $name));
         } else {
-            assertNotNull($disabledAttribute, sprintf("Failed asserting element '%s' is disabled", $name));
+            Assert::assertNotNull($disabledAttribute, sprintf("Failed asserting element '%s' is disabled", $name));
         }
     }
 
@@ -864,11 +865,11 @@ public function stepFieldShouldBeEnabled($field)
     {
         $page = $this->getSession()->getPage();
         $fieldElement = $page->findField($field);
-        assertNotNull($fieldElement, sprintf("Field '%s' not found", $field));
+        Assert::assertNotNull($fieldElement, sprintf("Field '%s' not found", $field));
 
         $disabledAttribute = $fieldElement->getAttribute('disabled');
 
-        assertNull($disabledAttribute, sprintf("Failed asserting field '%s' is enabled", $field));
+        Assert::assertNull($disabledAttribute, sprintf("Failed asserting field '%s' is enabled", $field));
     }
 
     /**
@@ -887,7 +888,7 @@ public function iFollowInTheRegion($link, $region)
     {
         $context = $this->getMainContext();
         $regionObj = $context->getRegionObj($region);
-        assertNotNull($regionObj);
+        Assert::assertNotNull($regionObj);
 
         $linkObj = $regionObj->findLink($link);
         if (empty($linkObj)) {
@@ -913,7 +914,7 @@ public function iFillinTheRegion($field, $value, $region)
     {
         $context = $this->getMainContext();
         $regionObj = $context->getRegionObj($region);
-        assertNotNull($regionObj, "Region Object is null");
+        Assert::assertNotNull($regionObj, "Region Object is null");
 
         $fieldObj = $regionObj->findField($field);
         if (empty($fieldObj)) {
@@ -943,7 +944,7 @@ public function iSeeTextInRegion($negate, $text, $region)
     {
         $context = $this->getMainContext();
         $regionObj = $context->getRegionObj($region);
-        assertNotNull($regionObj);
+        Assert::assertNotNull($regionObj);
 
         $actual = $regionObj->getText();
         $actual = preg_replace('/\s+/u', ' ', $actual);
@@ -987,7 +988,7 @@ public function iSelectTheRadioButton($radioLabel)
             'radio',
             $this->getMainContext()->getXpathEscaper()->escapeLiteral($radioLabel)
         ]);
-        assertNotNull($radioButton);
+        Assert::assertNotNull($radioButton);
         $session->getDriver()->click($radioButton->getXPath());
     }
 
@@ -1001,7 +1002,7 @@ public function theTableShouldContain($selector, $text)
         $table = $this->getTable($selector);
 
         $element = $table->find('named', array('content', "'$text'"));
-        assertNotNull($element, sprintf('Element containing `%s` not found in `%s` table', $text, $selector));
+        Assert::assertNotNull($element, sprintf('Element containing `%s` not found in `%s` table', $text, $selector));
     }
 
     /**
@@ -1014,7 +1015,7 @@ public function theTableShouldNotContain($selector, $text)
         $table = $this->getTable($selector);
 
         $element = $table->find('named', array('content', "'$text'"));
-        assertNull($element, sprintf('Element containing `%s` not found in `%s` table', $text, $selector));
+        Assert::assertNull($element, sprintf('Element containing `%s` not found in `%s` table', $text, $selector));
     }
 
     /**
@@ -1027,7 +1028,7 @@ public function iClickOnInTheTable($text, $selector)
         $table = $this->getTable($selector);
 
         $element = $table->find('xpath', sprintf('//*[count(*)=0 and contains(.,"%s")]', $text));
-        assertNotNull($element, sprintf('Element containing `%s` not found', $text));
+        Assert::assertNotNull($element, sprintf('Element containing `%s` not found', $text));
         $element->click();
     }
 
@@ -1065,7 +1066,7 @@ protected function getTable($selector)
         // Some tables don't have a visible title, so look for a fieldset with data-name instead
         $candidates += $page->findAll('xpath', "//fieldset[@data-name=$selector]//table");
 
-        assertTrue((bool)$candidates, 'Could not find any table elements');
+        Assert::assertTrue((bool)$candidates, 'Could not find any table elements');
 
         $table = null;
         /** @var NodeElement $candidate */
@@ -1075,7 +1076,7 @@ protected function getTable($selector)
             }
         }
 
-        assertTrue((bool)$table, 'Found table elements, but none are visible');
+        Assert::assertTrue((bool)$table, 'Found table elements, but none are visible');
 
         return $table;
     }
@@ -1092,19 +1093,19 @@ protected function getTable($selector)
     public function theTextBeforeAfter($textBefore, $order, $textAfter, $element)
     {
         $ele = $this->getSession()->getPage()->find('css', $element);
-        assertNotNull($ele, sprintf('%s not found', $element));
+        Assert::assertNotNull($ele, sprintf('%s not found', $element));
 
         // Check both of the texts exist in the element
         $text = $ele->getText();
-        assertTrue(strpos($text, $textBefore) !== 'FALSE', sprintf('%s not found in the element %s', $textBefore, $element));
-        assertTrue(strpos($text, $textAfter) !== 'FALSE', sprintf('%s not found in the element %s', $textAfter, $element));
+        Assert::assertTrue(strpos($text, $textBefore) !== 'FALSE', sprintf('%s not found in the element %s', $textBefore, $element));
+        Assert::assertTrue(strpos($text, $textAfter) !== 'FALSE', sprintf('%s not found in the element %s', $textAfter, $element));
 
         /// Use strpos to get the position of the first occurrence of the two texts (case-sensitive)
         // and compare them with the given order (before or after)
         if ($order === 'before') {
-            assertTrue(strpos($text, $textBefore) < strpos($text, $textAfter));
+            Assert::assertTrue(strpos($text, $textBefore) < strpos($text, $textAfter));
         } else {
-            assertTrue(strpos($text, $textBefore) > strpos($text, $textAfter));
+            Assert::assertTrue(strpos($text, $textBefore) > strpos($text, $textAfter));
         }
     }
 
@@ -1213,7 +1214,7 @@ public function iScrollToField($locator, $type)
     {
         $page = $this->getSession()->getPage();
         $el = $page->find('named', array($type, "'$locator'"));
-        assertNotNull($el, sprintf('%s element not found', $locator));
+        Assert::assertNotNull($el, sprintf('%s element not found', $locator));
 
         $id = $el->getAttribute('id');
         if (empty($id)) {
@@ -1236,7 +1237,7 @@ public function iScrollToField($locator, $type)
     public function iScrollToElement($locator)
     {
         $el = $this->getSession()->getPage()->find('css', $locator);
-        assertNotNull($el, sprintf('The element "%s" is not found', $locator));
+        Assert::assertNotNull($el, sprintf('The element "%s" is not found', $locator));
 
         $id = $el->getAttribute('id');
         if (empty($id)) {
@@ -1305,7 +1306,7 @@ public function iShouldSeeTheElement($selector)
 return document.querySelector("$sel");
 JS;
         $element = $this->getSession()->evaluateScript($js);
-        assertNotNull($element, sprintf('Element %s not found', $selector));
+        Assert::assertNotNull($element, sprintf('Element %s not found', $selector));
     }
 
     /**
diff --git a/src/Context/EmailContext.php b/src/Context/EmailContext.php
index d3e73c51..b30180bf 100644
--- a/src/Context/EmailContext.php
+++ b/src/Context/EmailContext.php
@@ -6,6 +6,7 @@
 use Behat\Behat\Hook\Scope\BeforeScenarioScope;
 use Behat\Gherkin\Node\TableNode;
 use Behat\Mink\Session;
+use PHPUnit\Framework\Assert;
 use SilverStripe\BehatExtension\Utility\TestMailer;
 use SilverStripe\Control\Email\Email;
 use SilverStripe\Control\Email\Mailer;
@@ -65,9 +66,9 @@ public function thereIsAnEmailFromTo($negate, $direction, $email)
         $from = ($direction == 'from') ? $email : null;
         $match = $this->mailer->findEmail($to, $from);
         if (trim($negate)) {
-            assertNull($match);
+            Assert::assertNull($match);
         } else {
-            assertNotNull($match);
+            Assert::assertNotNull($match);
         }
         $this->lastMatchedEmail = $match;
     }
@@ -89,7 +90,7 @@ public function thereIsAnEmailFromToTitled($negate, $direction, $email, $subject
             return $email->Subject;
         }, $allMails)) . '"' : null;
         if (trim($negate)) {
-            assertNull($match);
+            Assert::assertNull($match);
         } else {
             $msg = sprintf(
                 'Could not find email %s "%s" titled "%s".',
@@ -100,7 +101,7 @@ public function thereIsAnEmailFromToTitled($negate, $direction, $email, $subject
             if ($allTitles) {
                 $msg .= ' Existing emails: ' . $allTitles;
             }
-            assertNotNull($match, $msg);
+            Assert::assertNotNull($match, $msg);
         }
         $this->lastMatchedEmail = $match;
     }
@@ -129,9 +130,9 @@ public function thereTheEmailContains($negate, $content)
         }
 
         if (trim($negate)) {
-            assertNotContains($content, $emailContent);
+            Assert::assertNotContains($content, $emailContent);
         } else {
-            assertContains($content, $emailContent);
+            Assert::assertContains($content, $emailContent);
         }
     }
 
@@ -155,7 +156,7 @@ public function thereTheEmailContainsPlainText($content)
         $emailPlainText = strip_tags($emailContent);
         $emailPlainText = preg_replace("/\h+/", " ", $emailPlainText);
 
-        assertContains($content, $emailPlainText);
+        Assert::assertContains($content, $emailPlainText);
     }
 
     /**
@@ -169,13 +170,13 @@ public function iGoToInTheEmailTo($linkSelector, $direction, $email)
         $to = ($direction == 'to') ? $email : null;
         $from = ($direction == 'from') ? $email : null;
         $match = $this->mailer->findEmail($to, $from);
-        assertNotNull($match);
+        Assert::assertNotNull($match);
 
         $crawler = new Crawler($match->Content);
         $linkEl = $crawler->selectLink($linkSelector);
-        assertNotNull($linkEl);
+        Assert::assertNotNull($linkEl);
         $link = $linkEl->attr('href');
-        assertNotNull($link);
+        Assert::assertNotNull($link);
 
         $this->getMainContext()->visit($link);
     }
@@ -192,13 +193,13 @@ public function iGoToInTheEmailToTitled($linkSelector, $direction, $email, $titl
         $to = ($direction == 'to') ? $email : null;
         $from = ($direction == 'from') ? $email : null;
         $match = $this->mailer->findEmail($to, $from, $title);
-        assertNotNull($match);
+        Assert::assertNotNull($match);
 
         $crawler = new Crawler($match->Content);
         $linkEl = $crawler->selectLink($linkSelector);
-        assertNotNull($linkEl);
+        Assert::assertNotNull($linkEl);
         $link = $linkEl->attr('href');
-        assertNotNull($link);
+        Assert::assertNotNull($link);
         $this->getMainContext()->visit($link);
     }
 
@@ -218,9 +219,9 @@ public function iGoToInTheEmail($linkSelector)
         $match = $this->lastMatchedEmail;
         $crawler = new Crawler($match->Content);
         $linkEl = $crawler->selectLink($linkSelector);
-        assertNotNull($linkEl);
+        Assert::assertNotNull($linkEl);
         $link = $linkEl->attr('href');
-        assertNotNull($link);
+        Assert::assertNotNull($link);
 
         $this->getMainContext()->visit($link);
     }
@@ -264,11 +265,11 @@ public function theEmailContainFollowingData($negate, TableNode $table)
         // For "should not contain"
         if (trim($negate)) {
             foreach ($rows as $row) {
-                assertNotContains($row[0], $emailContent);
+                Assert::assertNotContains($row[0], $emailContent);
             }
         } else {
             foreach ($rows as $row) {
-                assertContains($row[0], $emailContent);
+                Assert::assertContains($row[0], $emailContent);
             }
         }
     }
@@ -282,13 +283,13 @@ public function thereIsAnEmailTitled($negate, $subject)
     {
         $match = $this->mailer->findEmail(null, null, $subject);
         if (trim($negate)) {
-            assertNull($match);
+            Assert::assertNull($match);
         } else {
             $msg = sprintf(
                 'Could not find email titled "%s".',
                 $subject
             );
-            assertNotNull($match, $msg);
+            Assert::assertNotNull($match, $msg);
         }
         $this->lastMatchedEmail = $match;
     }
@@ -306,9 +307,9 @@ public function theEmailSentFrom($negate, $from)
 
         $match = $this->lastMatchedEmail;
         if (trim($negate)) {
-            assertNotContains($from, $match->From);
+            Assert::assertNotContains($from, $match->From);
         } else {
-            assertContains($from, $match->From);
+            Assert::assertContains($from, $match->From);
         }
     }
 
@@ -325,9 +326,9 @@ public function theEmailSentTo($negate, $to)
 
         $match = $this->lastMatchedEmail;
         if (trim($negate)) {
-            assertNotContains($to, $match->To);
+            Assert::assertNotContains($to, $match->To);
         } else {
-            assertContains($to, $match->To);
+            Assert::assertContains($to, $match->To);
         }
     }
 
@@ -358,7 +359,7 @@ public function iClickOnHttpLinkInEmail($httpText)
                 break;
             }
         }
-        assertNotNull($href);
+        Assert::assertNotNull($href);
 
         $this->getMainContext()->visit($href);
     }
diff --git a/src/Context/FixtureContext.php b/src/Context/FixtureContext.php
index 007c344e..209c7c5d 100644
--- a/src/Context/FixtureContext.php
+++ b/src/Context/FixtureContext.php
@@ -9,6 +9,7 @@
 use Behat\Gherkin\Node\TableNode;
 use Exception;
 use InvalidArgumentException;
+use PHPUnit\Framework\Assert;
 use SilverStripe\Assets\Folder;
 use SilverStripe\Assets\Storage\AssetStore;
 use SilverStripe\Core\ClassInfo;
@@ -650,7 +651,7 @@ public function stepGoToNamedRecord($type, $id)
     public function iAddAnExtensionToTheClass($extension, $class)
     {
         // Validate the extension
-        assertTrue(
+        Assert::assertTrue(
             class_exists($extension) && is_subclass_of($extension, Extension::class),
             'Given extension does not extend Extension'
         );
@@ -696,9 +697,9 @@ protected function getDestinationConfigFolder($filename)
     {
         $project = ModuleManifest::config()->get('project') ?: 'mysite';
         $mysite = ModuleLoader::getModule($project);
-        assertNotNull($mysite, 'Project exists');
+        Assert::assertNotNull($mysite, 'Project exists');
         $destPath = $mysite->getResource("_config/{$filename}")->getPath();
-        assertFileNotExists($destPath, "Config file {$filename} hasn't aleady been loaded");
+        Assert::assertFileDoesNotExist($destPath, "Config file {$filename} hasn't aleady been loaded");
         return $destPath;
     }
 
@@ -712,7 +713,7 @@ protected function getDestinationConfigFolder($filename)
      */
     public function stepThereShouldBeAFileOrFolder($type, $path)
     {
-        assertFileExists($this->joinPaths(BASE_PATH, $path));
+        Assert::assertFileExists($this->joinPaths(BASE_PATH, $path));
     }
 
     /**
@@ -727,7 +728,7 @@ public function stepThereShouldBeAFileOrFolder($type, $path)
     public function stepThereShouldBeAFileWithTuple($filename, $hash)
     {
         $exists = $this->getAssetStore()->exists($filename, $hash);
-        assertTrue((bool)$exists, "A file exists with filename $filename and hash $hash");
+        Assert::assertTrue((bool)$exists, "A file exists with filename $filename and hash $hash");
     }
 
     /**
diff --git a/src/Context/LoginContext.php b/src/Context/LoginContext.php
index a7007ea0..54255d20 100644
--- a/src/Context/LoginContext.php
+++ b/src/Context/LoginContext.php
@@ -4,6 +4,7 @@
 
 use Behat\Behat\Context\Context;
 use Behat\Mink\Element\NodeElement;
+use PHPUnit\Framework\Assert;
 use SilverStripe\Security\Authenticator;
 use SilverStripe\Security\Group;
 use SilverStripe\Security\Member;
@@ -32,7 +33,7 @@ public function stepIAmLoggedIn()
 
         if (0 == strpos($this->getMainContext()->getSession()->getCurrentUrl(), $loginUrl)) {
             $this->stepILogInWith('admin', 'password');
-            assertStringStartsWith($adminUrl, $this->getMainContext()->getSession()->getCurrentUrl());
+            Assert::assertStringStartsWith($adminUrl, $this->getMainContext()->getSession()->getCurrentUrl());
         }
     }
 
@@ -63,13 +64,13 @@ public function stepIAmNotLoggedIn()
 
         $page = $this->getMainContext()->getSession()->getPage();
         $form = $page->findById('LogoutForm_Form');
-        assertNotNull($form, 'Logout form not found');
+        Assert::assertNotNull($form, 'Logout form not found');
 
         $submitButton = $form->find('css', '[type=submit]');
         $securityID = $form->find('css', '[name=SecurityID]');
 
-        assertNotNull($submitButton, 'Submit button on logout form not found');
-        assertNotNull($securityID, 'CSRF token not found');
+        Assert::assertNotNull($submitButton, 'Submit button on logout form not found');
+        Assert::assertNotNull($securityID, 'CSRF token not found');
 
         $submitButton->press();
     }
@@ -86,7 +87,7 @@ public function stepILogInWith($email, $password)
         $this->getMainContext()->getSession()->visit($loginUrl);
         $page = $this->getMainContext()->getSession()->getPage();
         $form = $page->findById('MemberLoginForm_LoginForm');
-        assertNotNull($form, 'Login form not found');
+        Assert::assertNotNull($form, 'Login form not found');
 
         // Try to find visible forms again on login page.
         $visibleForm = null;
@@ -94,17 +95,17 @@ public function stepILogInWith($email, $password)
         if ($form->isVisible() && $form->find('css', '[name=Email]')) {
             $visibleForm = $form;
         }
-        assertNotNull($visibleForm, 'Could not find login email field');
+        Assert::assertNotNull($visibleForm, 'Could not find login email field');
 
         $emailField = $visibleForm->find('css', '[name=Email]');
         $passwordField = $visibleForm->find('css', '[name=Password]');
         $submitButton = $visibleForm->find('css', '[type=submit]');
         $securityID = $visibleForm->find('css', '[name=SecurityID]');
 
-        assertNotNull($emailField, 'Email field on login form not found');
-        assertNotNull($passwordField, 'Password field on login form not found');
-        assertNotNull($submitButton, 'Submit button on login form not found');
-        assertNotNull($securityID, 'CSRF token not found');
+        Assert::assertNotNull($emailField, 'Email field on login form not found');
+        Assert::assertNotNull($passwordField, 'Password field on login form not found');
+        Assert::assertNotNull($submitButton, 'Submit button on login form not found');
+        Assert::assertNotNull($securityID, 'CSRF token not found');
 
         $emailField->setValue($email);
         $passwordField->setValue($password);
@@ -119,7 +120,7 @@ public function stepILogInWith($email, $password)
         $page = $this->getMainContext()->getSession()->getPage();
         $message = $page->find('css', '.message.error');
         $error = $message ? $message->getText() : null;
-        assertNull($message, 'Could not log in with user ' . $email . '. Error: "' . $error. '""');
+        Assert::assertNull($message, 'Could not log in with user ' . $email . '. Error: "' . $error. '""');
     }
 
     /**
@@ -129,7 +130,7 @@ public function stepIShouldSeeALogInForm()
     {
         $page = $this->getMainContext()->getSession()->getPage();
         $loginForm = $page->find('css', '#MemberLoginForm_LoginForm');
-        assertNotNull($loginForm, 'I should see a log-in form');
+        Assert::assertNotNull($loginForm, 'I should see a log-in form');
     }
 
     /**
@@ -139,7 +140,7 @@ public function stepIShouldSeeALogOutForm()
     {
         $page = $this->getMainContext()->getSession()->getPage();
         $logoutForm = $page->find('css', '#LogoutForm_Form');
-        assertNotNull($logoutForm, 'I should see a log-out form');
+        Assert::assertNotNull($logoutForm, 'I should see a log-out form');
     }
 
     /**
@@ -150,7 +151,7 @@ public function stepIWillSeeALogInMessage($type)
     {
         $page = $this->getMainContext()->getSession()->getPage();
         $message = $page->find('css', sprintf('.message.%s', $type));
-        assertNotNull($message, sprintf('%s message not found.', $type));
+        Assert::assertNotNull($message, sprintf('%s message not found.', $type));
     }
 
     /**
@@ -163,10 +164,10 @@ public function stepPasswordForEmailShouldBe($id, $password)
     {
         /** @var Member $member */
         $member = Member::get()->filter('Email', $id)->First();
-        assertNotNull($member);
+        Assert::assertNotNull($member);
         $authenticators = Security::singleton()->getApplicableAuthenticators(Authenticator::CHECK_PASSWORD);
         foreach ($authenticators as $authenticator) {
-            assertTrue($authenticator->checkPassword($member, $password)->isValid());
+            Assert::assertTrue($authenticator->checkPassword($member, $password)->isValid());
         }
     }
 
diff --git a/tests/php/SilverStripeContextTest.php b/tests/php/SilverStripeContextTest.php
index e9b8c1a2..78058992 100644
--- a/tests/php/SilverStripeContextTest.php
+++ b/tests/php/SilverStripeContextTest.php
@@ -8,6 +8,7 @@
 use Behat\Mink\Mink;
 use Behat\Mink\Driver\DriverInterface;
 use Behat\Mink\Element\Element;
+use PHPUnit\Framework\MockObject\MockObject;
 use SilverStripe\BehatExtension\Tests\SilverStripeContextTest\FeatureContext;
 use SilverStripe\Dev\SapphireTest;
 
@@ -16,22 +17,18 @@ class SilverStripeContextTest extends SapphireTest
 
     protected $backupGlobals = false;
 
-    /**
-     * @expectedException \LogicException
-     * @expectedExceptionMessage Cannot find 'region_map' in the behat.yml
-     */
     public function testGetRegionObjThrowsExceptionOnUnknownSelector()
     {
+        $this->expectException(\LogicException::class);
+        $this->expectExceptionMessage("Cannot find 'region_map' in the behat.yml");
         $context = $this->getContextMock();
         $context->getRegionObj('.unknown');
     }
 
-    /**
-     * @expectedException \LogicException
-     * @expectedExceptionMessage Cannot find the specified region in the behat.yml
-     */
     public function testGetRegionObjThrowsExceptionOnUnknownRegion()
     {
+        $this->expectException(\LogicException::class);
+        $this->expectExceptionMessage("Cannot find the specified region in the behat.yml");
         $context = $this->getContextMock();
         $context->setRegionMap(array('MyRegion' => '.my-region'));
         $context->getRegionObj('.unknown');
@@ -92,7 +89,7 @@ protected function getContextMock()
     }
 
     /**
-     * @return Element|\PHPUnit_Framework_MockObject_MockObject
+     * @return Element|MockObject
      */
     protected function getElementMock()
     {