diff --git a/src/__init__.py b/src/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/demo_wv.py b/src/apptest/demo_wv.py
similarity index 67%
rename from src/demo_wv.py
rename to src/apptest/demo_wv.py
index 1ad2e3c..e951116 100644
--- a/src/demo_wv.py
+++ b/src/apptest/demo_wv.py
@@ -6,8 +6,18 @@
 #   - TODO: find a cleaner solution for organisation (maybe just config to pytest?)
 
 import streamlit as st
-import whale_viewer as sw_wv
 
+# to run streamlit from this subdir, we need the the src dir on the path
+# NOTE: pytest doesn't need this to run the tests, but to develop the test
+# harness is hard without running streamlit 
+import sys
+from os import path
+# src (parent from here)
+src_dir = path.dirname( path.dirname( path.abspath(__file__) ) )
+sys.path.append(src_dir)
+
+
+import whale_viewer as sw_wv
 
 # a menu to pick one of the images 
 title = st.title("Whale Viewer testing")
diff --git a/tests/test_demo_wv.py b/tests/test_demo_wv.py
index 722c53c..8a3de62 100644
--- a/tests/test_demo_wv.py
+++ b/tests/test_demo_wv.py
@@ -17,7 +17,7 @@ def test_selectbox_ok():
     - finally, we check there are the right number of options (26)
     
     '''
-    at = AppTest.from_file("src/demo_wv.py").run()
+    at = AppTest.from_file("src/apptest/demo_wv.py").run()
     assert len(at.selectbox) == 1
     assert at.selectbox[0].value == "beluga"
     assert at.selectbox[0].index == 0
@@ -62,7 +62,7 @@ def test_img_props():
     - then changing the image, we do the same checks again
     
     '''
-    at = AppTest.from_file("src/demo_wv.py").run()
+    at = AppTest.from_file("src/apptest/demo_wv.py").run()
     ix = 0 # we didn't interact with the dropdown, so it should be the first one
     # could fetch the property - maybe better in case code example changes
     ix = at.selectbox[0].index