diff --git a/dp_creator_ii/tests/test_app.py b/dp_creator_ii/tests/test_app.py
index 27b4f19..5264a6f 100644
--- a/dp_creator_ii/tests/test_app.py
+++ b/dp_creator_ii/tests/test_app.py
@@ -21,29 +21,37 @@ def expect_visible(text):
     def expect_not_visible(text):
         expect(page.get_by_text(text)).not_to_be_visible()
 
+    def expect_no_error():
+        expect(page.locator(".shiny-output-error")).not_to_be_attached()
+
     page.goto(app.url)
     expect(page).to_have_title("DP Creator II")
     expect_visible(pick_dataset_text)
     expect_not_visible(perform_analysis_text)
     expect_not_visible(download_results_text)
-    expect_not_visible("expected str, bytes")
+    expect_no_error()
 
     csv_path = Path(__file__).parent / "fixtures" / "fake.csv"
     page.get_by_label("Choose CSV file").set_input_files(csv_path.resolve())
     expect_visible("student_id")
+    expect_no_error()
 
     page.get_by_role("button", name="Define analysis").click()
     expect_not_visible(pick_dataset_text)
     expect_visible(perform_analysis_text)
     expect_not_visible(download_results_text)
+    expect_no_error()
 
     page.get_by_role("button", name="Download results").click()
     expect_not_visible(pick_dataset_text)
     expect_not_visible(perform_analysis_text)
     expect_visible(download_results_text)
+    expect_no_error()
 
     with page.expect_download() as download_info:
         page.get_by_text("Download script").click()
+    expect_no_error()
+
     download = download_info.value
     script = download.path().read_text()
     assert "privacy_unit=dp.unit_of(contributions=1)" in script