1 files changed, 96 insertions, 0 deletions
diff --git a/src/app/surface-protocol.test.ts b/src/app/surface-protocol.test.ts
new file mode 100644
index 0000000..405e561
--- /dev/null
+++ b/src/app/surface-protocol.test.ts
@@ -0,0 +1,96 @@
+import type { SurfaceSpec } from "@dispatch/ui-contract";
+import { describe, expect, it, vi } from "vitest";
+import { createSurfaceProtocol } from "./surface-protocol.svelte";
+
+const spec: SurfaceSpec = { id: "s1", region: "inline", title: "Snapshot", fields: [] };
+
+function fixture() {
+  let focusedId = "c1";
+  const surfaces = createSurfaceProtocol({
+    focusedConversationId: () => focusedId,
+    send: vi.fn(),
+  });
+  surfaces.handleServerMessage({
+    type: "catalog",
+    catalog: [{ id: "s1", region: "inline", title: "Snapshot", scope: "conversation" }],
+  });
+  return {
+    surfaces,
+    focus(id: string) {
+      focusedId = id;
+      surfaces.syncSubscriptions();
+    },
+  };
+}
+
+describe("conversation-scoped surface lookup", () => {
+  it("keeps retained rendering but withholds another conversation's snapshot from decisions", () => {
+    const { surfaces, focus } = fixture();
+    expect(surfaces.surfaceSpecOp("s1", "c1")).toBeNull();
+    surfaces.handleServerMessage({ type: "surface", conversationId: "c1", spec });
+    expect(surfaces.surfaceSpecOp("s1", "c1")).toEqual(spec);
+    focus("c2");
+    expect(surfaces.surfaceSpecOp("s1")).toEqual(spec);
+    expect(surfaces.surfaceSpecOp("s1", "c2")).toBeNull();
+    surfaces.handleServerMessage({ type: "surface", conversationId: "c1", spec });
+    expect(surfaces.surfaceSpecOp("s1", "c2")).toBeNull();
+    const updated = { ...spec, title: "Current" };
+    surfaces.handleServerMessage({
+      type: "update",
+      update: { surfaceId: "s1", conversationId: "c2", spec: updated },
+    });
+    expect(surfaces.surfaceSpecOp("s1", "c2")).toEqual(updated);
+    expect(surfaces.surfaceSpecOp("s1", "c1")).toBeNull();
+  });
+
+  it("does not treat an unscoped snapshot as known conversation-specific data", () => {
+    const { surfaces } = fixture();
+    surfaces.handleServerMessage({ type: "surface", spec });
+    expect(surfaces.surfaceSpecOp("s1")).toEqual(spec);
+    expect(surfaces.surfaceSpecOp("s1", "c1")).toBeNull();
+  });
+
+  it("drops snapshot scope on explicit unsubscribe and catalog removal", () => {
+    const { surfaces } = fixture();
+    surfaces.handleServerMessage({ type: "surface", conversationId: "c1", spec });
+    surfaces.unsubscribeSurfaceOp("s1");
+    expect(surfaces.surfaceSpecOp("s1", "c1")).toBeNull();
+    surfaces.subscribeSurfaceOp("s1");
+    expect(surfaces.surfaceSpecOp("s1", "c1")).toBeNull();
+    surfaces.handleServerMessage({ type: "surface", conversationId: "c1", spec });
+    expect(surfaces.surfaceSpecOp("s1", "c1")).toEqual(spec);
+    surfaces.handleServerMessage({ type: "catalog", catalog: [] });
+    expect(surfaces.surfaceSpecOp("s1", "c1")).toBeNull();
+  });
+});
+
+describe("surface subscription budget", () => {
+  it("bounds a large catalog and releases old slots before subscribing a replacement catalog", () => {
+    const live = new Set<string>();
+    let peak = 0;
+    const surfaces = createSurfaceProtocol({
+      focusedConversationId: () => "chat",
+      send(message) {
+        if (message.type === "subscribe") live.add(message.surfaceId);
+        if (message.type === "unsubscribe") live.delete(message.surfaceId);
+        peak = Math.max(peak, live.size);
+      },
+    });
+    for (const prefix of ["old", "new"]) {
+      surfaces.handleServerMessage({
+        type: "catalog",
+        catalog: Array.from({ length: 339 }, (_, i) => ({
+          id: `${prefix}-${i}`,
+          region: "inline",
+          title: "Surface",
+          scope: "global" as const,
+        })),
+      });
+      expect(live.size).toBe(128);
+      expect([...live].every((id) => id.startsWith(prefix))).toBe(true);
+    }
+    surfaces.subscribeSurfaceOp("overflow");
+    expect(live.has("overflow")).toBe(false);
+    expect(peak).toBe(128);
+  });
+});