feat: session reattach via ReattachingRemote (adopts saved session id)

tests/unit/test_reattach.py

@@ -0,0 +1,41 @@
+from selenium.common.exceptions import WebDriverException
+
+from wabot.hosts import ReattachingRemote, attach, build_options
+
+
+class TestReattachingRemote:
+    def test_adopts_session_id_without_creating_a_session(self):
+        driver = ReattachingRemote(
+            "http://127.0.0.1:1", "saved-session-id", options=build_options("chromium")
+        )
+        # base __init__ resets session_id to None BEFORE start_session runs;
+        # our override must still win
+        assert driver.session_id == "saved-session-id"
+        assert isinstance(driver.caps, dict)
+
+    def test_works_for_firefox_options_too(self):
+        driver = ReattachingRemote(
+            "http://127.0.0.1:1", "sid", options=build_options("firefox")
+        )
+        assert driver.session_id == "sid"
+
+
+class TestAttach:
+    def test_returns_driver_when_probe_succeeds(self, monkeypatch):
+        monkeypatch.setattr(
+            ReattachingRemote, "current_url", property(lambda self: "http://example.com")
+        )
+        driver = attach("http://127.0.0.1:1", "sid", "chromium")
+        assert driver is not None
+        assert driver.session_id == "sid"
+
+    def test_returns_none_when_session_is_dead(self, monkeypatch):
+        def boom(self):
+            raise WebDriverException("invalid session id")
+
+        monkeypatch.setattr(ReattachingRemote, "current_url", property(boom))
+        assert attach("http://127.0.0.1:1", "sid", "chromium") is None
+
+    def test_returns_none_when_server_is_unreachable(self):
+        # no server on port 1: connection refused is immediate; attach must not raise
+        assert attach("http://127.0.0.1:1", "sid", "chromium") is None