feat(protocol): add browser contracts

packages/protocol/test/browser-control.test.ts

@@ -0,0 +1,53 @@
+import { describe, expect, test } from "bun:test"
+import { BrowserControlProtocol } from "../src/browser-control.js"
+import { Effect } from "effect"
+
+describe("BrowserControlProtocol", () => {
+  test("decodes text and Bun-compatible UTF-8 byte messages", async () => {
+    const message = '{"type":"browser.control.sync","revision":1,"attachments":[]}'
+    expect(await Effect.runPromise(BrowserControlProtocol.decodeFromDesktop(message))).toEqual({
+      type: "browser.control.sync",
+      revision: 1,
+      attachments: [],
+    })
+    expect(
+      await Effect.runPromise(BrowserControlProtocol.decodeFromDesktop(new TextEncoder().encode(message))),
+    ).toEqual({
+      type: "browser.control.sync",
+      revision: 1,
+      attachments: [],
+    })
+  })
+
+  test("round trips both control directions", async () => {
+    const desktop = { type: "browser.control.sync" as const, revision: 1, attachments: [] }
+    const server = { type: "browser.control.synced" as const, revision: 1 }
+    expect(
+      await Effect.runPromise(BrowserControlProtocol.decodeFromDesktop(BrowserControlProtocol.encodeFromDesktop(desktop))),
+    ).toEqual(desktop)
+    expect(
+      await Effect.runPromise(BrowserControlProtocol.decodeFromServer(BrowserControlProtocol.encodeFromServer(server))),
+    ).toEqual(server)
+  })
+
+  test("rejects excess properties and oversized messages", async () => {
+    expect(
+      await Effect.runPromise(
+        BrowserControlProtocol.decodeFromDesktop(
+          '{"type":"browser.control.sync","revision":1,"attachments":[],"extra":true}',
+        ).pipe(Effect.result),
+      ),
+    ).toMatchObject({ _tag: "Failure", failure: { _tag: "BrowserControlProtocol.MessageError" } })
+
+    expect(
+      await Effect.runPromise(
+        BrowserControlProtocol.decodeFromDesktop(new Uint8Array(BrowserControlProtocol.MaxMessageBytes + 1)).pipe(
+          Effect.result,
+        ),
+      ),
+    ).toMatchObject({
+      _tag: "Failure",
+      failure: { _tag: "BrowserControlProtocol.MessageError", kind: "too_large" },
+    })
+  })
+})