Tests: linkcheck: add remote-URL-redirection-ignored test case

tests/test_builders/test_build_linkcheck.py

@@ -966,7 +966,7 @@ def test_TooManyRedirects_on_HEAD(app, monkeypatch):
 
 
 @pytest.mark.sphinx('linkcheck', testroot='linkcheck-localserver')
-def test_ignore_redirection(app):
+def test_ignore_local_redirection(app):
     with serve_application(app, InfiniteRedirectOnHeadHandler) as address:
         app.config.linkcheck_ignore = [f'http://{address}/redirected']
         app.build()
@@ -983,6 +983,37 @@ def test_ignore_redirection(app):
     }
 
 
+class RemoteDomainRedirectHandler(InfiniteRedirectOnHeadHandler):
+    protocol_version = 'HTTP/1.1'
+
+    def do_GET(self):
+        self.send_response(301, 'Found')
+        if self.path == '/':
+            self.send_header('Location', '/local')
+        elif self.path == '/local':
+            self.send_header('Location', 'http://example.test/migrated')
+        self.send_header('Content-Length', '0')
+        self.end_headers()
+
+
+@pytest.mark.sphinx('linkcheck', testroot='linkcheck-localserver')
+def test_ignore_remote_redirection(app):
+    with serve_application(app, RemoteDomainRedirectHandler) as address:
+        app.config.linkcheck_ignore = [f'http://example.test']
+        app.build()
+
+    with open(app.outdir / 'output.json', encoding='utf-8') as fp:
+        content = json.load(fp)
+    assert content == {
+        'code': 301,
+        'status': 'ignored',
+        'filename': 'index.rst',
+        'lineno': 1,
+        'uri': f'http://{address}/',
+        'info': f'ignored redirect: http://example.test/migrated',
+    }
+
+
 def make_retry_after_handler(
     responses: list[tuple[int, str | None]],
 ) -> type[BaseHTTPRequestHandler]: