Update integration tests for enable_folder_selection API

- Rename test_upfd001 to test_upfd001_folder_upload_with_enable_folder_selection
- Add test_upfd002_multiple_files_without_folder_selection to verify multiple=True without folder selection
- Add test_upfd003_single_file_upload for single file upload validation
- Update tests to use enable_folder_selection prop instead of relying on multiple=True

Author: LeticiaBN

components/dash-core-components/tests/integration/upload/test_folder_upload.py

@@ -1,13 +1,13 @@
 from dash import Dash, Input, Output, dcc, html
 
 
-def test_upfd001_folder_upload_with_multiple(dash_dcc):
+def test_upfd001_folder_upload_with_enable_folder_selection(dash_dcc):
     """
-    Test that folder upload is enabled when multiple=True.
+    Test that folder upload is enabled when enable_folder_selection=True.
 
     Note: Full end-to-end testing of folder upload functionality is limited
     by Selenium's capabilities. This test verifies the component renders
-    correctly with multiple=True which enables folder support.
+    correctly with enable_folder_selection=True which enables folder support.
     """
     app = Dash(__name__)
 
@@ -17,7 +17,7 @@ def test_upfd001_folder_upload_with_multiple(dash_dcc):
             dcc.Upload(
                 id="upload-folder",
                 children=html.Div(
-                    ["Drag and Drop or ", html.A("Select Files or Folders")]
+                    ["Drag and Drop or ", html.A("Select Folder")]
                 ),
                 style={
                     "width": "100%",
@@ -28,7 +28,8 @@ def test_upfd001_folder_upload_with_multiple(dash_dcc):
                     "borderRadius": "5px",
                     "textAlign": "center",
                 },
-                multiple=True,  # Enables folder upload
+                multiple=True,
+                enable_folder_selection=True,  # Enables folder selection
                 accept=".txt,.csv",  # Test accept filtering
             ),
             html.Div(id="output"),
@@ -52,21 +53,77 @@ def update_output(contents_list):
     # Verify the upload component and input are present
     dash_dcc.wait_for_element("#upload-folder")
 
-    # Verify the input has folder selection attributes when multiple=True
+    # Verify the input has folder selection attributes when enable_folder_selection=True
     upload_input = dash_dcc.wait_for_element("#upload-folder input[type=file]")
     webkitdir_attr = upload_input.get_attribute("webkitdirectory")
 
     assert webkitdir_attr == "true", (
-        f"webkitdirectory attribute should be 'true' when multiple=True, "
+        f"webkitdirectory attribute should be 'true' when enable_folder_selection=True, "
         f"but got '{webkitdir_attr}'"
     )
 
     assert dash_dcc.get_logs() == [], "browser console should contain no error"
 
 
-def test_upfd002_folder_upload_disabled_with_single(dash_dcc):
+def test_upfd002_multiple_files_without_folder_selection(dash_dcc):
     """
-    Test that folder upload is NOT enabled when multiple=False.
+    Test that multiple file upload does NOT enable folder selection
+    when enable_folder_selection=False (default).
+    """
+    app = Dash(__name__)
+
+    app.layout = html.Div(
+        [
+            html.Div("Multiple Files Test", id="title"),
+            dcc.Upload(
+                id="upload-multiple",
+                children=html.Div(["Drag and Drop or ", html.A("Select Multiple Files")]),
+                style={
+                    "width": "100%",
+                    "height": "60px",
+                    "lineHeight": "60px",
+                    "borderWidth": "1px",
+                    "borderStyle": "dashed",
+                    "borderRadius": "5px",
+                    "textAlign": "center",
+                },
+                multiple=True,  # Allows multiple files
+                enable_folder_selection=False,  # But NOT folder selection
+                accept=".txt,.csv",  # Accept should work with file picker
+            ),
+            html.Div(id="output", children="Upload ready"),
+        ]
+    )
+
+    dash_dcc.start_server(app)
+
+    # Wait for the component to render
+    dash_dcc.wait_for_text_to_equal("#title", "Multiple Files Test")
+    dash_dcc.wait_for_text_to_equal("#output", "Upload ready")
+
+    # Verify the input does NOT have folder selection attributes
+    upload_input = dash_dcc.wait_for_element("#upload-multiple input[type=file]")
+    webkitdir_attr = upload_input.get_attribute("webkitdirectory")
+
+    # webkitdirectory should not be set when enable_folder_selection=False
+    assert webkitdir_attr in [None, "", "false"], (
+        f"webkitdirectory attribute should not be 'true' when enable_folder_selection=False, "
+        f"but got '{webkitdir_attr}'"
+    )
+
+    # Verify multiple attribute is set
+    multiple_attr = upload_input.get_attribute("multiple")
+    assert multiple_attr == "true", (
+        f"multiple attribute should be 'true' when multiple=True, "
+        f"but got '{multiple_attr}'"
+    )
+
+    assert dash_dcc.get_logs() == [], "browser console should contain no error"
+
+
+def test_upfd003_single_file_upload(dash_dcc):
+    """
+    Test that single file upload does NOT enable folder selection.
     """
     app = Dash(__name__)
 
@@ -85,7 +142,8 @@ def test_upfd002_folder_upload_disabled_with_single(dash_dcc):
                     "borderRadius": "5px",
                     "textAlign": "center",
                 },
-                multiple=False,  # Folder upload should be disabled
+                multiple=False,  # Single file only
+                accept="application/pdf",
             ),
             html.Div(id="output", children="Upload ready"),
         ]