error handling on contributions

dp_wizard/app/dataset_panel.py

@@ -31,6 +31,7 @@ def dataset_ui():
             cli_info.contributions,
             min=1,
         ),
+        ui.output_text("contributions_error"),
         ui.output_ui("python_tooltip_ui"),
         output_code_sample("Unit of Privacy", "unit_of_privacy_python"),
         ui.output_ui("define_analysis_button_ui"),
@@ -58,7 +59,7 @@ def _on_contributions_change():
 
     @reactive.calc
     def button_enabled():
-        contributions_is_set = input.contributions() is not None
+        contributions_is_set = int(input.contributions() or 0) >= 1
         csv_path_is_set = (
             input.csv_path() is not None and len(input.csv_path()) > 0
         ) or is_demo
@@ -80,6 +81,11 @@ def contributions_demo_tooltip_ui():
             f"can occur at most {contributions()} times in the dataset. ",
         )
 
+    @render.text
+    def contributions_error():
+        if not int(input.contributions() or 0) >= 1:
+            raise Exception("Contributions must be at least 1.")
+
     @render.ui
     def python_tooltip_ui():
         return demo_tooltip(

tests/test_app.py

@@ -51,12 +51,26 @@ def expect_no_error():
     # Button disabled until upload:
     define_analysis_button = page.get_by_role("button", name="Define analysis")
     assert define_analysis_button.is_disabled()
+    button_error = "Choose CSV and Contributions before proceeding"
+    expect_visible(button_error)
 
     # Now upload:
     csv_path = Path(__file__).parent / "fixtures" / "fake.csv"
     page.get_by_label("Choose CSV file").set_input_files(csv_path.resolve())
     expect_no_error()
 
+    # Contributions error checks:
+    contributions_error = "Contributions must be at least 1"
+    page.get_by_label("Contributions").fill("")
+    expect_visible(contributions_error)
+    expect_visible(button_error)
+    page.get_by_label("Contributions").fill("0")
+    expect_visible(contributions_error)
+    expect_visible(button_error)
+    page.get_by_label("Contributions").fill("42")
+    expect_not_visible(contributions_error)
+    expect_not_visible(button_error)
+
     # -- Define analysis --
     define_analysis_button.click()
     expect_not_visible(pick_dataset_text)