Add a test of the scrollspy

Author: peytondmurray

tests/sites/colors/index.rst

@@ -21,6 +21,26 @@ Heading 3
 
 Some text with a |code link|_.
 
+Heading 4
+---------
+
+Some other text
+
+Heading 5
+---------
+
+Some other text
+
+Heading 6
+---------
+
+Some other text
+
+Heading 7
+---------
+
+Some other text
+
 
 .. the below replacement is included to emulate what intersphinx / autodoc / numpydoc generate (links on text formatted as code), which (sadly) can't be done using nesting of standard rST markup.
 

tests/test_playwright.py

@@ -143,3 +143,37 @@ def check_colors():
                 expect(el).to_have_css("color", hover_color)
 
     _check_test_site(site_name, site_path, check_colors)
+
+
+def test_secondary_sidebar_toc_scrollspy(
+    sphinx_build_factory: Callable,
+    page: Page,
+    url_base: str,
+) -> None:
+    """Test that the secondary sidebar TOC highlights the correct item upon scroll."""
+    site_name = "colors"
+    site_path = _build_test_site(site_name, sphinx_build_factory=sphinx_build_factory)
+
+    def check_toc():
+        page.goto(urljoin(url_base, f"playwright_tests/{site_name}/index.html"))
+
+        # Wait until at least one of these gets activated by the js
+        page.wait_for_function(
+            "document.querySelector('#pst-page-toc-nav a.active') !== null"
+        )
+
+        toclinks = page.locator("#pst-page-toc-nav a.nav-link").element_handles()
+        headings = []
+        for handle in toclinks:
+            headings.append(
+                page.locator(handle.get_attribute("href")).first.element_handle()
+            )
+
+        # Upon first page load, the first element should be active
+        assert "active" in toclinks[0].get_attribute("class")
+        page.evaluate("window.scrollTo(0, document.body.scrollHeight)")
+
+        # After scrolling down, the first element shouldn't be active anymore
+        assert "active" not in toclinks[0].get_attribute("class")
+
+    _check_test_site(site_name, site_path, check_toc)