fix: align reply threading refs

src/auto-reply/reply/reply-reference.test.ts

@@ -0,0 +1,56 @@
+import { describe, expect, it } from "vitest";
+
+import { createReplyReferencePlanner } from "./reply-reference.js";
+
+describe("createReplyReferencePlanner", () => {
+  it("disables references when mode is off", () => {
+    const planner = createReplyReferencePlanner({
+      replyToMode: "off",
+      startId: "parent",
+    });
+    expect(planner.use()).toBeUndefined();
+    expect(planner.hasReplied()).toBe(false);
+  });
+
+  it("uses startId once when mode is first", () => {
+    const planner = createReplyReferencePlanner({
+      replyToMode: "first",
+      startId: "parent",
+    });
+    expect(planner.use()).toBe("parent");
+    expect(planner.hasReplied()).toBe(true);
+    planner.markSent();
+    expect(planner.use()).toBeUndefined();
+  });
+
+  it("returns startId for every call when mode is all", () => {
+    const planner = createReplyReferencePlanner({
+      replyToMode: "all",
+      startId: "parent",
+    });
+    expect(planner.use()).toBe("parent");
+    expect(planner.use()).toBe("parent");
+  });
+
+  it("prefers existing thread id regardless of mode", () => {
+    const planner = createReplyReferencePlanner({
+      replyToMode: "off",
+      existingId: "thread-1",
+      startId: "parent",
+    });
+    expect(planner.use()).toBe("thread-1");
+    expect(planner.hasReplied()).toBe(true);
+  });
+
+  it("honors allowReference=false", () => {
+    const planner = createReplyReferencePlanner({
+      replyToMode: "all",
+      startId: "parent",
+      allowReference: false,
+    });
+    expect(planner.use()).toBeUndefined();
+    expect(planner.hasReplied()).toBe(false);
+    planner.markSent();
+    expect(planner.hasReplied()).toBe(true);
+  });
+});