App testing cheat sheet

Text elements

from streamlit.testing.v1 import AppTest

at = AppTest.from_file("cheatsheet_app.py")

# Headers
assert "My app" in at.title[0].value
assert "New topic" in at.header[0].value
assert "Interesting sub-topic" in at.subheader[0].value
assert len(at.divider) == 2

# Body / code
assert "Hello, world!" in at.markdown[0].value
assert "import streamlit as st" in at.code[0].value
assert "A cool diagram" in at.caption[0].value
assert "Hello again, world!" in at.text[0].value
assert "\int a x^2 \,dx" in at.latex[0].value

Input widgets

from streamlit.testing.v1 import AppTest

at = AppTest.from_file("cheatsheet_app.py")

# button
assert at.button[0].value == False
at.button[0].click().run()
assert at.button[0].value == True

# checkbox
assert at.checkbox[0].value == False
at.checkbox[0].check().run() # uncheck() is also supported
assert at.checkbox[0].value == True

# color_picker
assert at.color_picker[0].value == "#FFFFFF"
at.color_picker[0].pick("#000000").run()

# date_input
assert at.date_input[0].value == datetime.date(2019, 7, 6)
at.date_input[0].set_value(datetime.date(2022, 12, 21)).run()

# form_submit_button - shows up just like a button
assert at.button[0].value == False
at.button[0].click().run()
assert at.button[0].value == True

# multiselect
assert at.multiselect[0].value == ["foo", "bar"]
at.multiselect[0].select("baz").unselect("foo").run()

# number_input
assert at.number_input[0].value == 5
at.number_input[0].increment().run()

# radio
assert at.radio[0].value == "Bar"
assert at.radio[0].index == 3
at.radio[0].set_value("Foo").run()

# selectbox
assert at.selectbox[0].value == "Bar"
assert at.selectbox[0].index == 3
at.selectbox[0].set_value("Foo").run()

# select_slider
assert at.select_slider[0].value == "Feb"
at.select_slider[0].set_value("Mar").run()
at.select_slider[0].set_range("Apr", "Jun").run()

# slider
assert at.slider[0].value == 2
at.slider[0].set_value(3).run()
at.slider[0].set_range(4, 6).run()

# text_area
assert at.text_area[0].value == "Hello, world!"
at.text_area[0].set_value("Hello, yourself!").run()

# text_input
assert at.text_input[0].value == "Hello, world!")
at.text_input[0].set_value("Hello, yourself!").run()

# time_input
assert at.time_input[0].value == datetime.time(8, 45)
at.time_input[0].set_value(datetime.time(12, 30))

# toggle
assert at.toggle[0].value == False
assert at.toggle[0].label == "Debug mode"
at.toggle[0].set_value(True).run()
assert at.toggle[0].value == True

Data elements

from streamlit.testing.v1 import AppTest

at = AppTest.from_file("cheatsheet_app.py")

# dataframe
expected_df = pd.DataFrame([1, 2, 3])
assert at.dataframe[0].value.equals(expected_df)

# metric
assert at.metric[0].value == "9500"
assert at.metric[0].delta == "1000"

# json
assert at.json[0].value == '["hi", {"foo": "bar"}]'

# table
table_df = pd.DataFrame([1, 2, 3])
assert at.table[0].value.equals(table_df)

Layouts and containers

from streamlit.testing.v1 import AppTest

at = AppTest.from_file("cheatsheet_app.py")

# sidebar
at.sidebar.text_input[0].set_value("Jane Doe")

# columns
at.columns[1].markdown[0].value == "Hello, world!"

# tabs
at.tabs[2].markdown[0].value == "Hello, yourself!"

Chat elements

from streamlit.testing.v1 import AppTest

at = AppTest.from_file("cheatsheet_app.py")

# chat_input
at.chat_input[0].set_value("Do you know any jokes?").run()
# Note: chat_input value clears after every re-run (like in a real app)

# chat_message
assert at.chat_message[0].markdown[0].value == "Do you know any jokes?"
assert at.chat_message[0].avatar == "user"

Status elements

from streamlit.testing.v1 import AppTest

at = AppTest.from_file("cheatsheet_app.py")

# exception
assert len(at.exception) == 1
assert "TypeError" in at.exception[0].value

# Other in-line alerts: success, info, warning, error
assert at.success[0].value == "Great job!"
assert at.info[0].value == "Please enter an API key to continue"
assert at.warning[0].value == "Sorry, the passwords didn't match"
assert at.error[0].value == "Something went wrong :("

# toast
assert at.toast[0].value == "That was lit!" and at.toast[0].icon == "🔥"

Limitations

As of Streamlit 1.28, the following Streamlit features are not natively supported by AppTest. However, workarounds are possible for many of them by inspecting the underlying proto directly using AppTest.get(). We plan to regularly add support for missing elements until all features are supported.

  • Chart elements (st.bar_chart, st.line_chart, etc)
  • Media elements (st.image, st.video, st.audio)
  • st.file_uploader
  • st.data_editor
  • st.expander
  • st.status
  • st.camera_input
  • st.download_button
  • st.link_button