diff --git a/tests/conftest.py b/tests/conftest.py
index 22153455..4cc25be7 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,17 +1,4 @@
 import os
 import shutil
 
-TO_REMOVE = [os.path.join('examples','valid_raw_data','metadata','annotations.csv'), os.path.join('output')]
-
-def pytest_sessionstart(session):
-    """
-    Called after the Session object has been created and
-    before performing collection and entering the run test loop.
-    """
-    for path in TO_REMOVE:
-        if os.path.exists(path):
-            if os.path.isdir(path):
-                shutil.rmtree(path)
-            else:
-                os.remove(path)
 
diff --git a/tests/test_annotations.py b/tests/test_annotations.py
index 568cc232..76142121 100644
--- a/tests/test_annotations.py
+++ b/tests/test_annotations.py
@@ -298,7 +298,7 @@ def dv_func(a, b, x, type):
     if type == 'number':
         return 1
     elif type == 'columns':
-        return pd.DataFrame([],columns=['segment_onset','segment_offset'])
+        return pd.DataFrame([], columns=['segment_onset','segment_offset'])
     elif type == 'normal':
         return x
 
@@ -306,18 +306,27 @@ def dv_func(a, b, x, type):
 # function used for derivation but does not hav correct signature
 def bad_func(a, b):
     return b
-@pytest.mark.parametrize("input_set,function,output_set,ow,error",
-                         [("missing", partial(dv_func,type='normal'), "output", False, AssertionError),
-                          ("derivation", partial(dv_func,type='number'), "output", False, None),
-                          ("derivation", partial(dv_func,type='columns'), "output", False, None),
-                          ("derivation", bad_func, "output", False, None),
-                          ("derivation", partial(dv_func,type='normal'), "derivation", False, AssertionError),
-                          ("input_reimport.csv", True, "imp_reimport_ow.csv", None, None),
-                          ("input_importoverlaps.csv", False, "imp_overlap.csv", "err_overlap.csv", None),
-                          ("input_import_duration_overflow.csv", False, None, None, AssertionError),
+@pytest.mark.parametrize("input_set,function,output_set,exists,ow,error",
+                         [("missing", partial(dv_func, type='normal'), "output", False, False, AssertionError),
+                          ("vtc_present", partial(dv_func, type='number'), "output", False, False, None),
+                          ("vtc_present", partial(dv_func, type='columns'), "output", False, False, None),
+                          ("vtc_present", bad_func, "output", False, False, None),
+                          ("vtc_present", partial(dv_func, type='normal'), "vtc_present", False, False, AssertionError),
+                          ("vtc_present", partial(dv_func, type='normal'), "output", True, False, AssertionError),
+                          ("vtc_present", partial(dv_func, type='normal'), "output", True, True, AssertionError),
                           ])
-def test_derive_inputs(project, am, input_set, function, output_set, ow, error):
-    pass
+def test_derive_inputs(project, am, input_set, function, output_set, exists, ow, error):
+    am.read()
+    # copy the input set to act as an existing output_set
+    if exists:
+        shutil.copytree(src=PATH / 'annotations' / 'vtc_present', dst=PATH / 'annotations' / output_set)
+        additions = am.annotations[am.annotations['set'] == input_set].copy()
+        additions['set'] = output_set
+        am.annotations = pd.concat([am.annotations, additions])
+
+    if error:
+        with pytest.raises(error):
+            am.rename_set(old, new)
 
 def test_intersect(project, am):
     input_annotations = pd.read_csv("examples/valid_raw_data/annotations/intersect.csv")
@@ -589,7 +598,6 @@ def test_rename(project, am, old, new, error, mf, index):
     tg_count = am.annotations[am.annotations["set"] == "textgrid"].shape[0]
 
     if error:
-        print(am.annotations[am.annotations["set"] == new].shape[0])
         with pytest.raises(error):
             am.rename_set(old, new)
     else: