Web search for pi through an existing Chrome over CDP

Attaches to a browser that is already running — never launches one —
using the same endpoint configuration as pi-browser-harness, so a single
/browser-target choice governs both packages.

One tool, castle_cdp_search, deliberately not named web_search so it
coexists with pi-web-access rather than shadowing it.

Notes from validating against castle's Chrome:

- tbs=qdr:*, the parameter Google's own Tools menu writes, renders an
  empty page on this profile; the older as_qdr=* works. Any date filter
  combined with udm=14 is also empty, so recency drops udm.
- Target.createTarget must not be raced against the abort signal:
  raceAbort abandons the promise but cannot cancel the command, and the
  command's side effect is a tab nothing is left holding.
- A search cancelled while queued has to be removed from the semaphore
  queue, or the slot handed to it later is never counted back.
- A decaying rate-limit block stops serving /sorry/ and returns an empty
  results page instead, indistinguishable from a genuine zero-hit search.

1 files changed, 64 insertions, 0 deletions

diff --git a/test/endpoint.test.ts b/test/endpoint.test.ts
new file mode 100644
index 0000000..f5c8236
--- /dev/null
+++ b/test/endpoint.test.ts
@@ -0,0 +1,64 @@
+import assert from "node:assert/strict";
+import { test } from "node:test";
+
+import {
+  DEFAULT_REMOTE_CDP,
+  LOCAL_CDP_PORT,
+  describeCdpTarget,
+  resolveCdpTarget,
+} from "../src/endpoint.ts";
+
+const ok = (resolution: ReturnType<typeof resolveCdpTarget>) => {
+  assert.equal(resolution.kind, "ok");
+  if (resolution.kind !== "ok") throw new Error("unreachable");
+  return resolution.target;
+};
+
+test("the built-in default parses — the fallback in resolveCdpTarget is unreachable", () => {
+  const target = ok(resolveCdpTarget({}, null));
+  assert.deepEqual(target, { host: "10.88.0.25", port: 9223, source: "default" });
+  assert.equal(`${target.host}:${target.port}`, DEFAULT_REMOTE_CDP);
+});
+
+test("BU_CDP_HTTP wins over a stored target", () => {
+  const target = ok(resolveCdpTarget({ BU_CDP_HTTP: "10.88.0.9:9333" }, "10.88.0.25:9223"));
+  assert.deepEqual(target, { host: "10.88.0.9", port: 9333, source: "env" });
+});
+
+test("a stored target is used when the environment is silent", () => {
+  const target = ok(resolveCdpTarget({}, "192.168.1.4:9222"));
+  assert.deepEqual(target, { host: "192.168.1.4", port: 9222, source: "stored" });
+});
+
+test("an empty BU_CDP_HTTP does not shadow the stored target", () => {
+  const target = ok(resolveCdpTarget({ BU_CDP_HTTP: "  " }, "192.168.1.4:9222"));
+  assert.equal(target.source, "stored");
+});
+
+test("the local aliases all resolve to this machine", () => {
+  for (const alias of ["local", "localhost", "off", "none", "0", "no", "LOCAL"]) {
+    const target = ok(resolveCdpTarget({ BU_CDP_HTTP: alias }, null));
+    assert.deepEqual(target, { host: "127.0.0.1", port: LOCAL_CDP_PORT, source: "env" }, alias);
+  }
+});
+
+test("IPv6-ish and malformed values are rejected rather than half-parsed", () => {
+  for (const raw of ["nonsense", "host:", ":9223", "host:0", "host:65536", "host:notaport"]) {
+    const resolution = resolveCdpTarget({ BU_CDP_HTTP: raw }, null);
+    assert.equal(resolution.kind, "invalid", raw);
+  }
+});
+
+test("a host with a port takes the last colon, so hostnames survive", () => {
+  const target = ok(resolveCdpTarget({ BU_CDP_HTTP: "castle.local:9223" }, null));
+  assert.deepEqual(target, { host: "castle.local", port: 9223, source: "env" });
+});
+
+test("describeCdpTarget names where the choice came from", () => {
+  assert.equal(
+    describeCdpTarget({ host: "10.88.0.25", port: 9223, source: "default" }),
+    "10.88.0.25:9223 (built-in default)",
+  );
+  assert.equal(describeCdpTarget({ host: "h", port: 1, source: "env" }), "h:1 (BU_CDP_HTTP)");
+  assert.equal(describeCdpTarget({ host: "h", port: 1, source: "stored" }), "h:1 (/browser-target)");
+});