diff --git a/redmapper/redmagic/redmagic_selector.py b/redmapper/redmagic/redmagic_selector.py
index c23b466..5a5625d 100644
--- a/redmapper/redmagic/redmagic_selector.py
+++ b/redmapper/redmagic/redmagic_selector.py
@@ -33,7 +33,7 @@ def __init__(self, conf, vlim_masks=None):
             Random number generator.
         """
 
-        if not isinstance(conf, Configuration):
+        if isinstance(conf, str):
             self.config = Configuration(conf)
         else:
             self.config = conf
diff --git a/tests/test_redmagic.py b/tests/test_redmagic.py
index 6c1328c..b700303 100644
--- a/tests/test_redmagic.py
+++ b/tests/test_redmagic.py
@@ -204,6 +204,8 @@ def setUp(self):
         self.test_dir = None
 
     def tearDown(self):
+        if "TXPIPE_NO_DELETE" in os.environ:
+            return
         if self.test_dir is not None:
             if os.path.exists(self.test_dir):
                 shutil.rmtree(self.test_dir, True)