refactor(pi): extract history image prune helpers

src/agents/pi-embedded-runner/run/history-image-prune.test.ts

@@ -0,0 +1,65 @@
+import type { AgentMessage } from "@mariozechner/pi-agent-core";
+import type { ImageContent } from "@mariozechner/pi-ai";
+import { describe, expect, it } from "vitest";
+import { PRUNED_HISTORY_IMAGE_MARKER, pruneProcessedHistoryImages } from "./history-image-prune.js";
+
+describe("pruneProcessedHistoryImages", () => {
+  const image: ImageContent = { type: "image", data: "abc", mimeType: "image/png" };
+
+  it("prunes image blocks from user messages that already have assistant replies", () => {
+    const messages: AgentMessage[] = [
+      {
+        role: "user",
+        content: [{ type: "text", text: "See /tmp/photo.png" }, { ...image }],
+      } as AgentMessage,
+      {
+        role: "assistant",
+        content: "got it",
+      } as unknown as AgentMessage,
+    ];
+
+    const didMutate = pruneProcessedHistoryImages(messages);
+
+    expect(didMutate).toBe(true);
+    const firstUser = messages[0] as Extract<AgentMessage, { role: "user" }> | undefined;
+    expect(Array.isArray(firstUser?.content)).toBe(true);
+    const content = firstUser?.content as Array<{ type: string; text?: string; data?: string }>;
+    expect(content).toHaveLength(2);
+    expect(content[0]?.type).toBe("text");
+    expect(content[1]).toMatchObject({ type: "text", text: PRUNED_HISTORY_IMAGE_MARKER });
+  });
+
+  it("does not prune latest user message when no assistant response exists yet", () => {
+    const messages: AgentMessage[] = [
+      {
+        role: "user",
+        content: [{ type: "text", text: "See /tmp/photo.png" }, { ...image }],
+      } as AgentMessage,
+    ];
+
+    const didMutate = pruneProcessedHistoryImages(messages);
+
+    expect(didMutate).toBe(false);
+    const first = messages[0] as Extract<AgentMessage, { role: "user" }> | undefined;
+    if (!first || !Array.isArray(first.content)) {
+      throw new Error("expected array content");
+    }
+    expect(first.content).toHaveLength(2);
+    expect(first.content[1]).toMatchObject({ type: "image", data: "abc" });
+  });
+
+  it("does not change messages when no assistant turn exists", () => {
+    const messages: AgentMessage[] = [
+      {
+        role: "user",
+        content: "noop",
+      } as AgentMessage,
+    ];
+
+    const didMutate = pruneProcessedHistoryImages(messages);
+
+    expect(didMutate).toBe(false);
+    const firstUser = messages[0] as Extract<AgentMessage, { role: "user" }> | undefined;
+    expect(firstUser?.content).toBe("noop");
+  });
+});