feat(admin-config-tool): task 5.6 - mock-controller push/dry-run coverage

Adds end-to-end propagation tests through push_config's real
composition with xceadmin.discovery (not just discovery.py's own
unit tests): a 4-mock-server redirect chain proving TooManyRedirectsError
surfaces correctly, and a monkeypatched-timeout test proving
NoPrimaryError does too, without waiting out a real 30s socket
timeout. Also locks in and documents a real wire-contract limitation:
ProbeConfigTagReply carries no rejection signal, so dry-run's
accepted=False path is unreachable today by design, not an oversight.

This completes all 18 sub-tasks in tasks.md.

src/xceadmin/tests/test_config_push_mock.py

@@ -22,7 +22,7 @@ from pathlib import Path
 import pytest
 
 from xcecommon import wire
-from xcecommon.errors import ReplyDecodeError
+from xcecommon.errors import ConnectionTimeoutError, NoPrimaryError, ReplyDecodeError, TooManyRedirectsError
 from xcecommon.schema import load_schema
 from xceadmin import push
 
@@ -268,3 +268,91 @@ def test_probe_config_zero_generation_still_accepted(mock_controller, cluster_bi
     assert result.current_generation == 0
     assert result.would_be_generation == 1
     assert result.accepted is True
+
+
+@pytest.mark.parametrize("tag_value", [0, 1, 999999])
+def test_probe_config_has_no_wire_level_rejection_signal_by_design(
+    mock_controller, cluster_bin, tag_value
+):
+    """5.6 asks for both an accepted and a rejected dry-run outcome, but
+    ``ProbeConfigTagReply`` (module docstring, ``push.py`` module
+    docstring) has only a bare ``configTag`` -- no field exists on the
+    real wire contract to signal rejection, matching the real C
+    reference client (``config_repl.c``'s ``xce_probe_config_tag``, which
+    also returns only a bare tag). This test locks in that limitation
+    explicitly rather than silently having no coverage for it: every
+    successful round-trip, regardless of the returned ``configTag``
+    value, yields ``accepted=True`` -- there is no reachable code path
+    that produces ``accepted=False`` today. A real "would this SHA be
+    accepted" check is future controller-side work (Requirement 6.1).
+    """
+    mod = load_schema()
+
+    def _handler(conn):
+        wire.recv_frame(conn)
+        reply = mod.ProbeConfigTagReply.new_message()
+        reply.configTag = tag_value
+        wire.send_frame(conn, reply.to_bytes())
+
+    srv = mock_controller(_handler)
+
+    result = push.probe_config(cluster_bin, f"127.0.0.1:{srv.port}", CERT_DIR)
+
+    assert result.accepted is True
+    assert result.reason == ""
+
+
+# ---------------------------------------------------------------------------
+# End-to-end redirect/discovery failure propagation through push_config
+# ---------------------------------------------------------------------------
+
+
+def test_push_config_propagates_too_many_redirects_end_to_end(mock_controller, cluster_bin):
+    """A real chain of 4 redirecting mock servers -- push_config's own
+    composition with xceadmin.discovery must surface TooManyRedirectsError,
+    not silently follow forever or return a bogus result.
+    """
+    mod = load_schema()
+    servers = {}
+
+    def _make_redirect_handler(next_port_getter):
+        def _handler(conn):
+            wire.recv_frame(conn)
+            reply = mod.RequestReply.new_message()
+            reply.status = 0
+            reply.redirectHost = "127.0.0.1"
+            reply.redirectPort = next_port_getter()
+            reply.data.nodata = None
+            wire.send_frame(conn, reply.to_bytes())
+
+        return _handler
+
+    # 5 servers: a -> b -> c -> d -> e (4 redirects, one too many).
+    names = ["a", "b", "c", "d", "e"]
+    for i, name in enumerate(names[:-1]):
+        next_name = names[i + 1]
+        servers[name] = mock_controller(_make_redirect_handler(lambda n=next_name: servers[n].port))
+    # The last server ('e') also redirects -- this is hop #4, exceeding the
+    # 3-hop limit before it would ever be contacted.
+    servers["e"] = mock_controller(_make_redirect_handler(lambda: 1))
+
+    with pytest.raises(TooManyRedirectsError):
+        push.push_config(cluster_bin, f"127.0.0.1:{servers['a'].port}", CERT_DIR)
+
+
+def test_push_config_propagates_no_primary_error_on_connection_timeout(cluster_bin, monkeypatch):
+    """xceadmin.discovery already unit-tests this conversion directly
+    (test_discovery.py); this proves push_config's actual composition
+    with it surfaces the same NoPrimaryError, without waiting out a real
+    30s socket timeout -- xcecommon.wire.connect is monkeypatched to
+    raise ConnectionTimeoutError immediately, exactly what it would
+    eventually raise on a genuine timeout.
+    """
+
+    def _fake_connect(host, port, cert_dir, timeout_s=30.0):
+        raise ConnectionTimeoutError(f"timeout connecting to {host}:{port}", host, port)
+
+    monkeypatch.setattr(wire, "connect", _fake_connect)
+
+    with pytest.raises(NoPrimaryError):
+        push.push_config(cluster_bin, "127.0.0.1:9991", CERT_DIR)