test: add tests for managing selenium webdriver

tests/viz/altair/test_saving.py

@@ -1,6 +1,7 @@
 import shutil
 from pathlib import Path
 from nesta_ds_utils.viz.altair import saving
+from selenium.webdriver.chromium.webdriver import ChromiumDriver
 import pandas as pd
 import altair as alt
 import pytest
@@ -41,3 +42,18 @@ def test_save_altair_exception():
         saving.save(
             fig, "test_fig", path, save_png=False, save_html=False, save_svg=False
         )
+
+
+def test_webdriver():
+    """Test that Chrome WebDriver is created by default is a ChromiumDriver, and context manager stops the webdriver."""
+    driver = saving._google_chrome_driver_setup()
+    assert isinstance(driver, ChromiumDriver)
+
+    with saving.webdriver_context(driver) as some_driver:
+        # No actions needed here,
+        # just testing that the context manager calls .quit() on driver to terminate.
+        pass
+
+    # If subprocess not terminated, .poll() returns None
+    # https://docs.python.org/3/library/subprocess.html#subprocess.Popen.returncode
+    assert driver.service.process.poll() is not None