test: debugging the mock / side-effect usage

- the rerun exec model of streamlit causes the mock's side effect to be
called multiple times, and this invalidates the data beyond the first
call. The true object doesn't behave in the same way (because the
callback is only triggered when the input files are changed). New
wrapper here gives stable behaviour

tests/test_demo_input_sidebar.py

@@ -21,17 +21,52 @@ from test_demo_multifile_upload import (
     MockUploadedFile, )
 
 
+# decorator that counts the number of times a function is called
+def count_calls(func):
+    def wrapper(*args, **kwargs):
+        wrapper.called += 1
+        return func(*args, **kwargs)
+    wrapper.called = 0
+    return wrapper
 
+
+@count_calls
 def wrapped_buffer_uploaded_files(*args, **kwargs):
     import streamlit as st
-    #import time
-    _cprint(f"[I] buffering files in my side-effect! cool")
-    #time.sleep(1)
     uploaded_files = st.session_state.file_uploader_data
     _cprint(f"[I] buffering files in my side-effect! cool | {len(uploaded_files)}")
+    for i, (key, img) in enumerate(st.session_state.images.items()):
+        _cprint(f"    - image {i}: {type(img)} [{key}]")
+
+    buffer_uploaded_files() # nowcall the real prod func
+    _cprint(f"[I] finished the real buffering ! cool | {len(uploaded_files)}")
+
+    
+@count_calls
+def wrapped_buffer_uploaded_files_allowed_once(*args, **kwargs):
+    # this is a wrapper that only allows the real function to be called once
+    # - this is to prevent the side-effect from being called multiple times
+    # - the callback is only invoked when the input data is changed for the 
+    #   real file_uploader object; but due to the 're-run script on interaction' 
+    #   model, the side-effect is called each time.
+    import streamlit as st
+    uploaded_files = st.session_state.file_uploader_data
+    if len(st.session_state.images) != 0:
+        _cprint(f"[I] buffering already called before, side-effect! not rerun inner func | {len(uploaded_files)} | {len(st.session_state.images)}")
+        for i, (key, img) in enumerate(st.session_state.images.items()):
+            _cprint(f"    - image {i}: {type(img)} [{key}]")
+        return
+    
+    _cprint(f"[I] buffering files in my side-effect! cool | {len(uploaded_files)}")
+    for i, (key, img) in enumerate(st.session_state.images.items()):
+        _cprint(f"    - image {i}: {type(img)} [{key}]")
+
     buffer_uploaded_files() # nowcall the real prod func
     _cprint(f"[I] finished the real buffering ! cool | {len(uploaded_files)}")
-# - tests for apptest/demo_input_phase
+    
+    
+
+# - tests for apptest/demo_input_sidebar 
 
 # zero test: no inputs 
 #   -> empty session state
@@ -222,10 +257,6 @@ def test_two_input_files_realdata(mock_file_rv: MagicMock, mock_uploadedFile_Lis
         assert at.sidebar.text_input(key=f"input_longitude_{hash}") is not None
         assert at.sidebar.date_input(key=f"input_date_{hash}") is not None
         assert at.sidebar.time_input(key=f"input_time_{hash}") is not None
-        
-        #elem = at.get('text_input',key=f"input_latitude_{hash}")
-        #print(f"found element: {elem}")
-        #assert f"input_latitude_{hash}" in at.text_input.values()
 
     if 'demo_input_sidebar' in SCRIPT_UNDER_TEST:
         verify_metadata_in_demo_display(at, num_files)