Testing a file download using Selenium - python

Question

I write automation tests in Selenium and use python and the chrome browser. I need to write a test that downloads a file (from a link ) and checks that the file has been downloaded. And if possible, the test checks the file type. How can I write this?

I managed to download the file using click(), but I don't know how to check if the file has been downloaded.

Answer 1

You can add download.default_directory to the ChromeOptions and instantiate the webdriver.Chrome with the options object. All the downloads made with this instance will be stored in the download.default_directory.

To make the test platform-agnostic you can use the tmp_path fixture provided by pytest, it will create a temporary directory for the downloaded files. But make sure you specify str(tmp_path) as the download.default_directory for the ChromeOptions.

Consider the following example, you can run it with pytest test_download.py:

# test_download.py

import os
import time
from dataclasses import dataclass
from pathlib import Path

import pytest
from selenium import webdriver


@dataclass
class Chrome:
    driver: webdriver.Chrome
    downloads: Path


@pytest.fixture(scope="function")
def chrome(tmp_path):
    options = webdriver.ChromeOptions()
    options.add_experimental_option(
        "prefs",
        {
            "download.default_directory": str(tmp_path),
        },
    )

    driver = webdriver.Chrome(options=options)

    yield Chrome(driver=driver, downloads=tmp_path)

    driver.quit()


def test_download_file(chrome: Chrome):
    filename = "sample4.csv"
    chrome.driver.get(f"https://filesamples.com/samples/document/csv/{filename}")

    # Wait for the file to download, adjust if needed
    time.sleep(1)

    # Check if the file has been downloaded
    assert filename in os.listdir(chrome.downloads)