Expand test coverage to include serve_preview for our base page model

bedrock/cms/tests/test_rendering.py

@@ -90,10 +90,8 @@ def test_locale_redirect_will_work_for_cms_pages__default_locale_not_available(
     assert redirect_to_best_locale_spy.call_count == 1
 
 
-def test_locales_are_drawn_from_page_translations(
-    minimal_site,
-    rf,
-):
+@pytest.mark.parametrize("serving_method", ("serve", "serve_preview"))
+def test_locales_are_drawn_from_page_translations(minimal_site, rf, serving_method):
     assert Locale.objects.count() == 2  # en-US and fr
     fr_locale = Locale.objects.get(language_code="fr")
 
@@ -107,7 +105,7 @@ def test_locales_are_drawn_from_page_translations(
     assert _relative_url == "/en-US/test-page/"
     request = rf.get(_relative_url)
 
-    resp = page.serve(request)
+    resp = getattr(page, serving_method)(request)
     page_content = str(resp.content)
     assert "Test Page" in page_content
     assert '<option lang="en-US" value="en-US" selected>English</option>' in page_content