diff --git a/.gitignore b/.gitignore
index b6de2c1..9e9d6e9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,11 +2,10 @@
 ### Composer template
 composer.phar
 /vendor/
-composer.lock
 
 # Commit your application's lock file https://getcomposer.org/doc/01-basic-usage.md#commit-your-composer-lock-file-to-version-control
 # You may choose to ignore a library lock file http://getcomposer.org/doc/02-libraries.md#lock-file
-# composer.lock
+composer.lock
 
 .phpunit.result.cache
 
@@ -16,4 +15,4 @@ composer.lock
 # but don't ignore the folder and composer.json
 # and configuration files.
 !/tests/fixtures/*/composer.json
-!/tests/fixtures/*/wp-translation-downloader.json
\ No newline at end of file
+!/tests/fixtures/*/wp-translation-downloader.json
diff --git a/composer.json b/composer.json
index cde4fdf..7ca2601 100644
--- a/composer.json
+++ b/composer.json
@@ -21,7 +21,7 @@
         "mikey179/vfsstream": "^v1.6.10",
         "composer/composer": "^2.3.7",
         "inpsyde/php-coding-standards": "^1.0.0",
-        "phpunit/phpunit": "^8.5.26",
+        "phpunit/phpunit": "^9.6.0",
         "vimeo/psalm": "^4.23.0",
         "ondram/ci-detector": "^4.1.0"
     },
@@ -48,7 +48,10 @@
         "behat": "@php ./vendor/bin/behat",
         "cs": "@php ./vendor/squizlabs/php_codesniffer/bin/phpcs",
         "psalm": "@php ./vendor/vimeo/psalm/psalm --no-cache --output-format=compact --find-unused-psalm-suppress",
-        "tests": "@php ./vendor/phpunit/phpunit/phpunit --coverage-text",
+        "tests": [
+            "@putenv XDEBUG_MODE=coverage",
+            "@php ./vendor/phpunit/phpunit/phpunit --coverage-text"
+        ],
         "tests:no-coverage": "@php ./vendor/phpunit/phpunit/phpunit --no-coverage",
         "tests:unit": "@php ./vendor/phpunit/phpunit/phpunit --testsuite Unit",
         "qa": [
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 8052521..62bc7e2 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,18 +1,16 @@
-<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/8.5/phpunit.xsd"
-         bootstrap="./tests/boot.php"
-         colors="true">
-    <filter>
-        <whitelist processUncoveredFilesFromWhitelist="true">
-            <directory suffix=".php">./src</directory>
-            <exclude>
-                <directory>./vendor</directory>
-            </exclude>
-        </whitelist>
-    </filter>
-    <testsuites>
-        <testsuite name="Unit">
-            <directory suffix="Test.php">./tests/Unit/</directory>
-        </testsuite>
-    </testsuites>
-</phpunit>
\ No newline at end of file
+<?xml version="1.0"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd" bootstrap="./tests/boot.php" colors="true">
+  <coverage processUncoveredFiles="true">
+    <include>
+      <directory suffix=".php">./src</directory>
+    </include>
+    <exclude>
+      <directory>./vendor</directory>
+    </exclude>
+  </coverage>
+  <testsuites>
+    <testsuite name="Unit">
+      <directory suffix="Test.php">./tests/Unit/</directory>
+    </testsuite>
+  </testsuites>
+</phpunit>