Make the test suite connectivity-agnostic (#12095)

Co-authored-by: Adam Turner <9087854+aa-turner@users.noreply.github.com>

sphinx/testing/fixtures.py

@@ -7,7 +7,7 @@ import subprocess
 import sys
 from collections import namedtuple
 from io import StringIO
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING
 
 import pytest
 
@@ -236,52 +236,6 @@ def if_graphviz_found(app: SphinxTestApp) -> None:  # NoQA: PT004
     pytest.skip('graphviz "dot" is not available')
 
 
-_HOST_ONLINE_ERROR = pytest.StashKey[Optional[str]]()
-
-
-def _query(address: tuple[str, int]) -> str | None:
-    import socket
-
-    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
-        try:
-            sock.settimeout(5)
-            sock.connect(address)
-        except OSError as exc:
-            # other type of errors are propagated
-            return str(exc)
-        return None
-
-
-@pytest.fixture(scope='session')
-def sphinx_remote_query_address() -> tuple[str, int]:
-    """Address to which a query is made to check that the host is online.
-
-    By default, onlineness is tested by querying the DNS server ``1.1.1.1``
-    but users concerned about privacy might change it in ``conftest.py``.
-    """
-    return ('1.1.1.1', 80)
-
-
-@pytest.fixture(scope='session')
-def if_online(  # NoQA: PT004
-    request: pytest.FixtureRequest,
-    sphinx_remote_query_address: tuple[str, int],
-) -> None:
-    """Skip the test if the host has no connection.
-
-    Usage::
-
-        @pytest.mark.usefixtures('if_online')
-        def test_if_host_is_online(): ...
-    """
-    if _HOST_ONLINE_ERROR not in request.session.stash:
-        # do not use setdefault() to avoid creating a socket connection
-        lookup_error = _query(sphinx_remote_query_address)
-        request.session.stash[_HOST_ONLINE_ERROR] = lookup_error
-    if (error := request.session.stash[_HOST_ONLINE_ERROR]) is not None:
-        pytest.skip('host appears to be offline (%s)' % error)
-
-
 @pytest.fixture(scope='session')
 def sphinx_test_tempdir(tmp_path_factory: Any) -> Path:
     """Temporary directory."""

tests/roots/test-images/index.rst

@@ -23,7 +23,7 @@ test-image
    :target: https://www.python.org/
 
 .. a remote image
-.. image:: https://www.python.org/static/img/python-logo.png
+.. image:: http://localhost:7777/sphinx.png
 
 .. non-exist remote image
-.. image:: https://www.google.com/NOT_EXIST.PNG
+.. image:: http://localhost:7777/NOT_EXIST.PNG

tests/roots/test-root/images.txt

@@ -12,9 +12,6 @@ Sphinx image handling
 .. an image with unspecified extension
 .. image:: img.*
 
-.. a non-local image URI
-.. image:: https://www.python.org/static/img/python-logo.png
-
 .. an image with subdir and unspecified extension
 .. image:: subdir/simg.*
 

tests/test_builders/test_build_html_image.py

@@ -5,15 +5,14 @@ import docutils
 import pytest
 
 
-@pytest.mark.usefixtures('if_online')
 @pytest.mark.sphinx('html', testroot='images')
 def test_html_remote_images(app, status, warning):
     app.build(force_all=True)
 
     result = (app.outdir / 'index.html').read_text(encoding='utf8')
-    assert ('<img alt="https://www.python.org/static/img/python-logo.png" '
-            'src="https://www.python.org/static/img/python-logo.png" />' in result)
-    assert not (app.outdir / 'python-logo.png').exists()
+    assert ('<img alt="http://localhost:7777/sphinx.png" '
+            'src="http://localhost:7777/sphinx.png" />' in result)
+    assert not (app.outdir / 'sphinx.png').exists()
 
 
 @pytest.mark.sphinx('html', testroot='image-escape')
@@ -25,7 +24,6 @@ def test_html_encoded_image(app, status, warning):
     assert (app.outdir / '_images/img_#1.png').exists()
 
 
-@pytest.mark.usefixtures('if_online')
 @pytest.mark.sphinx('html', testroot='remote-logo')
 def test_html_remote_logo(app, status, warning):
     app.build(force_all=True)

tests/test_builders/test_build_latex.py

@@ -1,5 +1,6 @@
 """Test the build process with LaTeX builder with the test root."""
 
+import http.server
 import os
 import re
 import subprocess
@@ -17,6 +18,8 @@ from sphinx.ext.intersphinx import setup as intersphinx_setup
 from sphinx.util.osutil import ensuredir
 from sphinx.writers.latex import LaTeXTranslator
 
+from tests.utils import http_server
+
 try:
     from contextlib import chdir
 except ImportError:
@@ -79,6 +82,28 @@ def skip_if_stylefiles_notfound(testfunc):
         return testfunc
 
 
+class RemoteImageHandler(http.server.BaseHTTPRequestHandler):
+    protocol_version = "HTTP/1.1"
+
+    def do_GET(self):
+        content, content_type = None, None
+        if self.path == "/sphinx.png":
+            with open("tests/roots/test-local-logo/images/img.png", "rb") as f:
+                content = f.read()
+                content_type = "image/png"
+
+        if content:
+            self.send_response(200, "OK")
+            self.send_header("Content-Length", str(len(content)))
+            self.send_header("Content-Type", content_type)
+            self.end_headers()
+            self.wfile.write(content)
+        else:
+            self.send_response(404, "Not Found")
+            self.send_header("Content-Length", "0")
+            self.end_headers()
+
+
 @skip_if_requested
 @skip_if_stylefiles_notfound
 @pytest.mark.parametrize(
@@ -112,7 +137,8 @@ def test_build_latex_doc(app, engine, docclass, python_maximum_signature_line_le
     load_mappings(app)
     app.builder.init()
     LaTeXTranslator.ignore_missing_images = True
-    app.build(force_all=True)
+    with http_server(RemoteImageHandler):
+        app.build(force_all=True)
 
     # file from latex_additional_files
     assert (app.outdir / 'svgimg.svg').is_file()
@@ -1398,21 +1424,21 @@ def test_latex_raw_directive(app, status, warning):
     assert 'LaTeX: abc def ghi' in result
 
 
-@pytest.mark.usefixtures('if_online')
 @pytest.mark.sphinx('latex', testroot='images')
 def test_latex_images(app, status, warning):
-    app.build(force_all=True)
+    with http_server(RemoteImageHandler, port=7777):
+        app.build(force_all=True)
 
     result = (app.outdir / 'python.tex').read_text(encoding='utf8')
 
     # images are copied
-    assert '\\sphinxincludegraphics{{python-logo}.png}' in result
-    assert (app.outdir / 'python-logo.png').exists()
+    assert '\\sphinxincludegraphics{{sphinx}.png}' in result
+    assert (app.outdir / 'sphinx.png').exists()
 
     # not found images
     assert '\\sphinxincludegraphics{{NOT_EXIST}.PNG}' not in result
     assert ('WARNING: Could not fetch remote image: '
-            'https://www.google.com/NOT_EXIST.PNG [404]' in warning.getvalue())
+            'http://localhost:7777/NOT_EXIST.PNG [404]' in warning.getvalue())
 
     # an image having target
     assert ('\\sphinxhref{https://www.sphinx-doc.org/}'
@@ -1682,7 +1708,7 @@ def test_copy_images(app, status, warning):
         image.name for image in test_dir.rglob('*')
         if image.suffix in {'.gif', '.pdf', '.png', '.svg'}
     }
-    images.discard('python-logo.png')
+    images.discard('sphinx.png')
     assert images == {
         'img.pdf',
         'rimg.png',