diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index cc24f121e..c69b306d0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -145,7 +145,9 @@ jobs:
           coverage: none
 
       - name: "Install Sphinx"
-        run: pip install sphinx myst-parser sphinx-rtd-theme
+        run: |
+          apt install pipx
+          pipx install sphinx myst-parser sphinx-rtd-theme
 
       - name: "Install dependencies with composer"
         uses: ramsey/composer-install@v3
diff --git a/tests/BuildDirTrait.php b/tests/BuildDirTrait.php
index 858b17731..fcc8be4fc 100644
--- a/tests/BuildDirTrait.php
+++ b/tests/BuildDirTrait.php
@@ -19,6 +19,7 @@ use function dirname, file_exists, file_get_contents, is_file, mkdir, realpath,
  */
 trait BuildDirTrait{
 
+	/** @var string */
 	private const _buildDir = __DIR__.'/../.build/';
 
 	/**