add unit tests for simple argument checks

tests/unit/test_browser.py

@@ -0,0 +1,44 @@
+import pytest
+from dash.testing.browser import Browser
+from dash.testing.consts import SELENIUM_GRID_DEFAULT
+
+
+@pytest.mark.parametrize("browser_type", ("Chrome", "Firefox"))
+def test_browser_smoke(browser_type, tmpdir):
+
+    browser = Browser(
+        browser=browser_type,
+        remote=False,
+        remote_url=SELENIUM_GRID_DEFAULT,
+        headless=True,
+        options=None,
+        download_path=tmpdir.mkdir("download").strpath,
+        percy_finalize=True,
+    )
+    assert browser.driver.name == browser_type.lower()
+
+
+def test_browser_use_remote_webdriver(tmpdir):
+    # test creation with remote=True
+    with pytest.raises(Exception):
+        Browser(
+            browser="Chrome",
+            remote=True,
+            remote_url=SELENIUM_GRID_DEFAULT,
+            headless=True,
+            options=None,
+            download_path=tmpdir.mkdir("download").strpath,
+            percy_finalize=True,
+        )
+
+    # test creation with remote_url other than default
+    with pytest.raises(Exception):
+        Browser(
+            browser="Chrome",
+            remote=False,
+            remote_url="http://token@any.selenium.grid:3333",
+            headless=True,
+            options=None,
+            download_path=tmpdir.mkdir("download").strpath,
+            percy_finalize=True,
+        )