use ellipsis to truncate breadcrumbs, and test with playwright (#1861)

This PR:

- Fixes breadcrumb truncation to use CSS `overflow: ellipsis`
- Provides an example for combining playwright and sphinx_build_factory
to more thoroughly test our theme components.
- Applies that approach to testing breadcrumb truncation via ellipsis
when the breadcrumb is placed in various parts of our layout.

joint work with @munkm and @drammock 

closes #1583 
closes #1568 
lays groundwork for addressing #229

---------

Co-authored-by: Daniel McCloy <[email protected]>
Co-authored-by: Madicken Munk <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: gabalafou <[email protected]>

src/pydata_sphinx_theme/assets/styles/components/_breadcrumbs.scss

@@ -13,6 +13,18 @@ ul.bd-breadcrumbs {
   li.breadcrumb-item {
     display: flex;
     align-items: center;
+    white-space: nowrap;
+    overflow-x: hidden;
+
+    a,
+    .ellipsis {
+      overflow-x: hidden;
+      text-overflow: ellipsis;
+
+      // Need to add margin, otherwise the overflow: hidden rule on the parent
+      // will hide the focus ring
+      margin: $focus-ring-width;
+    }
 
     // Style should look like heavier in-page links
     // keeping visited in the default link colour

src/pydata_sphinx_theme/assets/styles/sections/_header-article.scss

@@ -1,18 +1,9 @@
 .header-article__inner {
-  display: flex;
   padding: 0 0.5rem;
 
   // The items define the height so that it disappears if there are no items
   .header-article-item {
     min-height: var(--pst-header-article-height);
-    height: var(--pst-header-article-height);
-  }
-
-  .header-article-items__start,
-  .header-article-items__end {
-    display: flex;
-    align-items: start;
-    gap: 0.5rem;
   }
 
   .header-article-items__end {

src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/breadcrumbs.html

@@ -1,12 +1,5 @@
 {# Displays (and links to) the parent section(s) of the currently viewed page. #}
 {%- block breadcrumbs %}
-{#
-  If we have more than 3 parents (excluding the home page) then we remove
-  The ones in the middle and add an ellipsis.
-#}
-{% if parents|length>2 %}
-{% set parents=[parents[0], {"title": '<i class="fa-solid fa-ellipsis"></i>'}, parents[-1]] %}
-{% endif %}
 
 {#- Hide breadcrumbs on the home page #}
 {% if title and pagename != root_doc %}
@@ -25,7 +18,7 @@
     <li class="breadcrumb-item">{{ doc.title }}</li>
     {% endif %}
     {%- endfor %}
-    <li class="breadcrumb-item active" aria-current="page">{{ title|truncate(15, False) }}</li>
+    <li class="breadcrumb-item active" aria-current="page"><span class="ellipsis">{{ title }}</span></li>
   </ul>
 </nav>
 {% endif %}

tests/conftest.py

@@ -1,9 +1,12 @@
 """Configuration of the pytest session."""
 
 import re
+import time
+from http.client import HTTPConnection
 from os import environ
 from pathlib import Path
 from shutil import copytree
+from subprocess import PIPE, Popen
 from typing import Callable
 
 import pytest
@@ -14,7 +17,9 @@
 
 pytest_plugins = "sphinx.testing.fixtures"
 
-path_tests = Path(__file__).parent
+tests_path = Path(__file__).parent
+repo_path = tests_path.parent
+docs_build_path = repo_path / "docs" / "_build" / "html"
 
 # -- Utils method ------------------------------------------------------------
 
@@ -81,8 +86,49 @@ def _func(src_folder: str, **kwargs) -> SphinxBuild:
 
             srcdir = sphinx_path(srcdir)
 
-        copytree(path_tests / "sites" / src_folder, tmp_path / src_folder)
+        copytree(tests_path / "sites" / src_folder, tmp_path / src_folder)
         app = make_app(srcdir=srcdir, **kwargs)
         return SphinxBuild(app, tmp_path / src_folder)
 
     yield _func
+
+
+@pytest.fixture(scope="module")
+def url_base():
+    """Start local server on built docs and return the localhost URL as the base URL."""
+    # Use a port that is not commonly used during development or else you will
+    # force the developer to stop running their dev server in order to run the
+    # tests.
+    port = "8213"
+    host = "localhost"
+    url = f"http://{host}:{port}"
+
+    # Try starting the server
+    process = Popen(
+        ["python", "-m", "http.server", port, "--directory", docs_build_path],
+        stdout=PIPE,
+    )
+
+    # Try connecting to the server
+    retries = 5
+    while retries > 0:
+        conn = HTTPConnection(host, port)
+        try:
+            conn.request("HEAD", "/")
+            response = conn.getresponse()
+            if response is not None:
+                yield url
+                break
+        except ConnectionRefusedError:
+            time.sleep(1)
+            retries -= 1
+
+    # If the code above never yields a URL, then we were never able to connect
+    # to the server and retries == 0.
+    if not retries:
+        raise RuntimeError("Failed to start http server in 5 seconds")
+    else:
+        # Otherwise the server started and this fixture is done now and we clean
+        # up by stopping the server.
+        process.terminate()
+        process.wait()

tests/sites/breadcrumbs/Makefile

@@ -0,0 +1,20 @@
+# Minimal makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line, and also
+# from the environment for the first two.
+SPHINXOPTS    ?=
+SPHINXBUILD   ?= sphinx-build
+SOURCEDIR     = .
+BUILDDIR      = _build
+
+# Put it first so that "make" without argument is like "make help".
+help:
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+
+.PHONY: help Makefile
+
+# Catch-all target: route all unknown targets to Sphinx using the new
+# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+%: Makefile
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)

tests/sites/breadcrumbs/conf.py

@@ -0,0 +1,32 @@
+"""Test conf file."""
+
+# -- Project information -----------------------------------------------------
+
+project = "PyData Tests"
+copyright = "2020, Pydata community"
+author = "Pydata community"
+
+root_doc = "index"
+
+# -- General configuration ---------------------------------------------------
+
+# Add any Sphinx extension module names here, as strings. They can be
+# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
+# ones.
+extensions = []
+html_theme = "pydata_sphinx_theme"
+html_logo = "_static/emptylogo.png"
+html_copy_source = True
+html_sourcelink_suffix = ""
+
+# Base options, we can add other key/vals later
+html_sidebars = {"section1/index": ["sidebar-nav-bs.html"]}
+
+html_theme_options = {
+    "footer_start": ["breadcrumbs"],
+    "footer_center": ["breadcrumbs"],
+    "footer_end": ["breadcrumbs"],
+    "primary_sidebar_end": ["breadcrumbs"],
+    "secondary_sidebar_items": ["breadcrumbs"],
+    "article_header_start": ["breadcrumbs"],
+}

tests/sites/breadcrumbs/hansel/gretel/house.rst

@@ -0,0 +1,2 @@
+In the oven with my sister, so hot right now. Soooo. Hotttt.
+============================================================

tests/sites/breadcrumbs/index.rst

@@ -0,0 +1,17 @@
+Index ``with code`` in title
+============================
+
+.. toctree::
+   :caption: My caption
+   :numbered:
+
+   hansel/gretel/house
+
+A header
+--------
+
+A sub-header
+~~~~~~~~~~~~
+
+A sub-sub-header
+````````````````

tests/sites/breadcrumbs/missing_url.json

@@ -0,0 +1,14 @@
+[
+  {
+    "name": "v0.7.1 (stable)",
+    "version": "0.7.1",
+    "url": "https://pydata-sphinx-theme.readthedocs.io/en/v0.7.1/"
+  },
+  {
+    "version": "0.7.0",
+    "url": "https://pydata-sphinx-theme.readthedocs.io/en/v0.7.0/"
+  },
+  {
+    "version": "0.6.3"
+  }
+]

tests/sites/breadcrumbs/switcher.json

@@ -0,0 +1,15 @@
+[
+  {
+    "name": "v0.7.1 (stable)",
+    "version": "0.7.1",
+    "url": "https://pydata-sphinx-theme.readthedocs.io/en/v0.7.1/"
+  },
+  {
+    "version": "0.7.0",
+    "url": "https://pydata-sphinx-theme.readthedocs.io/en/v0.7.0/"
+  },
+  {
+    "version": "0.6.3",
+    "url": "https://pydata-sphinx-theme.readthedocs.io/en/v0.6.3/"
+  }
+]

tests/test_a11y.py

@@ -1,9 +1,5 @@
 """Using Axe-core, scan the Kitchen Sink pages for accessibility violations."""
 
-import time
-from http.client import HTTPConnection
-from pathlib import Path
-from subprocess import PIPE, Popen
 from urllib.parse import urljoin
 
 import pytest
@@ -25,50 +21,6 @@
 # people. It just means that page is free of common testable accessibility
 # pitfalls.
 
-path_repo = Path(__file__).parent.parent
-path_docs_build = path_repo / "docs" / "_build" / "html"
-
-
-@pytest.fixture(scope="module")
-def url_base():
-    """Start local server on built docs and return the localhost URL as the base URL."""
-    # Use a port that is not commonly used during development or else you will
-    # force the developer to stop running their dev server in order to run the
-    # tests.
-    port = "8213"
-    host = "localhost"
-    url = f"http://{host}:{port}"
-
-    # Try starting the server
-    process = Popen(
-        ["python", "-m", "http.server", port, "--directory", path_docs_build],
-        stdout=PIPE,
-    )
-
-    # Try connecting to the server
-    retries = 5
-    while retries > 0:
-        conn = HTTPConnection(host, port)
-        try:
-            conn.request("HEAD", "/")
-            response = conn.getresponse()
-            if response is not None:
-                yield url
-                break
-        except ConnectionRefusedError:
-            time.sleep(1)
-            retries -= 1
-
-    # If the code above never yields a URL, then we were never able to connect
-    # to the server and retries == 0.
-    if not retries:
-        raise RuntimeError("Failed to start http server in 5 seconds")
-    else:
-        # Otherwise the server started and this fixture is done now and we clean
-        # up by stopping the server.
-        process.terminate()
-        process.wait()
-
 
 def filter_ignored_violations(violations, url_pathname):
     """Filter out ignored axe-core violations.
@@ -227,24 +179,6 @@ def test_axe_core(
     assert len(filtered_violations) == 0, format_violations(filtered_violations)
 
 
-def test_version_switcher_highlighting(page: Page, url_base: str) -> None:
-    """This isn't an a11y test, but needs a served site for Javascript to inject the version menu."""
-    page.goto(url=url_base)
-    # no need to include_hidden here ↓↓↓, we just need to get the active version name
-    button = page.get_by_role("button").filter(has_text="dev")
-    active_version_name = button.get_attribute("data-active-version-name")
-    # here we do include_hidden, so sidebar & topbar menus should each have a matching entry:
-    entries = page.get_by_role("option", include_hidden=True).filter(
-        has_text=active_version_name
-    )
-    assert entries.count() == 2
-    # make sure they're highlighted
-    for entry in entries.all():
-        light_mode = "rgb(10, 125, 145)"  # pst-color-primary
-        # dark_mode = "rgb(63, 177, 197)"
-        expect(entry).to_have_css("color", light_mode)
-
-
 @pytest.mark.a11y
 def test_code_block_tab_stop(page: Page, url_base: str) -> None:
     """Code blocks that have scrollable content should be tab stops."""
@@ -306,3 +240,14 @@ def test_notebook_ipywidget_output_tab_stop(page: Page, url_base: str) -> None:
     # ...and so our js code on the page should make it keyboard-focusable
     # (tabIndex = 0)
     assert ipywidget.evaluate("el => el.tabIndex") == 0
+
+
+def test_breadcrumb_expansion(page: Page, url_base: str) -> None:
+    """Foo."""
+    # page.goto(urljoin(url_base, "community/practices/merge.html"))
+    # expect(page.get_by_label("Breadcrumb").get_by_role("list")).to_contain_text("Merge and review policy")
+    page.set_viewport_size({"width": 1440, "height": 720})
+    page.goto(urljoin(url_base, "community/topics/config.html"))
+    expect(page.get_by_label("Breadcrumb").get_by_role("list")).to_contain_text(
+        "Update Sphinx configuration during the build"
+    )