Model websocket adapter failures with tagged errors

ts/packages/client/src/__tests__/websocket-adapter.test.ts

@@ -0,0 +1,72 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import {
+  getRandomValues as fillRandomValues,
+  getWebSocketConstructor,
+  WebSocketAdapterError,
+  WS_OPEN,
+} from "../socket/websocket-adapter.js";
+
+class FakeWebSocket {
+  readonly readyState = WS_OPEN;
+
+  constructor(readonly url: string) {}
+
+  send(_data: string): void {}
+
+  close(_code?: number, _reason?: string): void {}
+
+  addEventListener(_type: string, _listener: (event: { readonly type: string }) => void): void {}
+
+  removeEventListener(_type: string, _listener: (event: { readonly type: string }) => void): void {}
+}
+
+describe("websocket adapter", () => {
+  afterEach(() => {
+    vi.unstubAllGlobals();
+  });
+
+  it("prefers a compatible global WebSocket constructor", () => {
+    vi.stubGlobal("WebSocket", FakeWebSocket);
+
+    const Constructor = getWebSocketConstructor();
+    const socket = new Constructor("ws://example.test/rpc");
+
+    expect(socket).toBeInstanceOf(FakeWebSocket);
+    expect(socket.readyState).toBe(WS_OPEN);
+  });
+
+  it("loads the optional ws constructor when no global WebSocket exists", () => {
+    vi.stubGlobal("WebSocket", undefined);
+
+    expect(getWebSocketConstructor()).toBeTypeOf("function");
+  });
+
+  it("uses global crypto when available", () => {
+    const getRandomValues = vi.fn((target: Uint32Array) => {
+      target[0] = 42;
+      return target;
+    });
+    vi.stubGlobal("crypto", { getRandomValues });
+
+    const values = fillRandomValues(new Uint32Array(1));
+
+    expect(values[0]).toBe(42);
+    expect(getRandomValues).toHaveBeenCalledOnce();
+  });
+
+  it("raises a typed error when no crypto source is available", () => {
+    vi.stubGlobal("crypto", undefined);
+
+    expect(() => fillRandomValues(new Uint32Array(2))).toThrow(WebSocketAdapterError);
+  });
+
+  it("exposes typed adapter errors", () => {
+    const error = WebSocketAdapterError.make({
+      operation: "test",
+      message: "typed",
+    });
+
+    expect(error._tag).toBe("WebSocketAdapterError");
+    expect(error.message).toBe("typed");
+  });
+});