diff --git a/tests/tool_dataflows_connector_compression_test.php b/tests/tool_dataflows_connector_compression_test.php
index b4d56a8d..e5bdebc0 100644
--- a/tests/tool_dataflows_connector_compression_test.php
+++ b/tests/tool_dataflows_connector_compression_test.php
@@ -45,6 +45,10 @@ protected function setUp(): void {
         set_config('gzip_exec_path', '/usr/bin/gzip', 'tool_dataflows');
     }
 
+    protected function tearDown(): void {
+        $this->basedir = null;
+    }
+
     /**
      * Creates a test dataflow
      *
diff --git a/tests/tool_dataflows_flow_compression_test.php b/tests/tool_dataflows_flow_compression_test.php
index ede4df22..77ea4596 100644
--- a/tests/tool_dataflows_flow_compression_test.php
+++ b/tests/tool_dataflows_flow_compression_test.php
@@ -58,6 +58,11 @@ protected function setUp(): void {
         set_config('permitted_dirs', $basedir, 'tool_dataflows');
     }
 
+    protected function tearDown(): void {
+        $this->readdir = null;
+        $this->outdir = null;
+    }
+
     /**
      * Creates a test dataflow
      *