Showcasing how to do tests for `elm/file` with selenium

[francescortiz]

Testing file open in Selenium

Greetings, I’m trying to test my Elm SPA using Selenium. My application supports saving JSON files to the user’s computer (using elm/file’s Download module) & opening them again with elm/file’s Select module. The problem is, elm/file creates an input node, but does not put it in the DOM (cf. File.js line 119) so Selenium cannot see it. Would you have any idea how I could open the JSON file from Selenium?

Following with that topic:

@Deimos I managed to do it. The solution is a bit hacky, but works, headless or not.

1. Hack to make selenium tests works in headless selenium driver. · GitHub
   This gist has the code that keeps a reference to the last 20 created input elements.

2. in selenium, inject that javascript before the form is created:

    with open("./scripts/hack-file-upload.js", "r") as f:
        patch_for_elm_file = f.read()

    driver.execute_script(patch_for_elm_file)
    time.sleep(1) # Not sure this is needed, but is late.

3. In seleinum, trigger the file dialog of the elm app.

4. Afterwards call set_file_image_elm_hack

# Awaiter is a custom class, just use regular wait.

def set_file_image_elm_hack(driver: WebDriver, offset: int, path: str):
    id = str(random.randint(111111111, 999999999))
    driver.execute_script("document.addFileInputToDom(arguments[0], arguments[1])", offset, id)

    file_input = WebDriverWait(driver, 30).until(ec.presence_of_element_located((By.XPATH, "//*[@test-id='" + id + "']")))
    file_input.send_keys(path)

    driver.execute_script("document.removeFileInputFromDom(arguments[0])", id)
    if not HEADLESS:
        time.sleep(1)
        subprocess.call(["./scripts/close_file_dialog.sh"])

5. This bash script closes the file dialog:

#!/usr/bin/env bash

# The window name is not the same in firefox. we should handle that if we need it.
win_name="Open File"

# Find window PID
for pid in $(xdotool search --name "$win_name"); do
  error=$(xdotool windowactivate $pid 2>&1)
  if [[ "$error" == "" ]]; then
    WIN=$pid
    break
  fi
done

if [[ "$WIN" == "" ]]; then
  echo "Failed to find file dialog window."
  exit 1
fi

# Switch to the window
xdotool windowactivate $WIN

# Press "Open" button
xdotool key --window $WIN alt+c

[Deimos]

Wow, thanks! I was going to resort to ports and stuff. I’ll definitely have to test your way, thanks!