my-pi/pi-compaction/test/segment-index.test.ts

import test from "node:test";
import assert from "node:assert/strict";
import { DEFAULT_CONFIG } from "../src/config.ts";
import { SegmentIndex, deterministicSummary } from "../src/segment-index.ts";

const assistant = {
  role: "assistant",
  content: [{ type: "toolCall", id: "call-1", name: "bash", arguments: { command: "npm test" } }],
  timestamp: 10,
};
const result = {
  role: "toolResult",
  toolCallId: "call-1",
  toolName: "bash",
  content: [{ type: "text", text: `failure\n${"x".repeat(12_000)}\nstack tail` }],
  isError: true,
  timestamp: 11,
};

test("deterministic summary is bounded and preserves head/tail evidence", () => {
  const summary = deterministicSummary({
    toolName: "bash",
    args: { command: "npm test" },
    rawText: result.content[0]!.text,
    isError: true,
    maxStubTokens: 256,
  });
  assert.match(summary, /tool=bash status=error/);
  assert.match(summary, /failure/);
  assert.match(summary, /stack tail/);
  assert.ok(summary.length <= 1_100);
});

test("projection incrementally replaces tool results and caches identical input", () => {
  const index = new SegmentIndex("session-1");
  index.hydrate([], DEFAULT_CONFIG);
  const records = index.captureTurn(assistant, [result], DEFAULT_CONFIG);
  assert.equal(records.length, 1);

  const messages = [assistant, result];
  const first = index.project(messages, {
    environmentHash: "env",
    environmentTokens: 100,
    contextWindow: 300_000,
  });
  const second = index.project(messages, {
    environmentHash: "env",
    environmentTokens: 100,
    contextWindow: 300_000,
  });

  assert.strictEqual(first, second);
  assert.ok(first.effectiveTokens < first.rawTokens);
  assert.match(first.messages[1]!.content[0].text, /context_tree_query/);

  const record = records[0]!;
  assert.ok(index.applySemantic(record.sourceKey, record.sourceHash, "- npm test failed\n- stack tail"));
  const semantic = index.project(messages, {
    environmentHash: "env",
    environmentTokens: 100,
    contextWindow: 300_000,
  });
  assert.notStrictEqual(semantic, first);
  assert.match(semantic.messages[1]!.content[0].text, /npm test failed/);
});

test("usage-backed baseline is adjusted only by projected delta", () => {
  const index = new SegmentIndex("session-2");
  index.hydrate([], DEFAULT_CONFIG);
  const initial = index.project([assistant], {
    environmentHash: "env",
    environmentTokens: 50,
    contextWindow: 100_000,
  });
  index.recordUsage(1_000, initial.messageEstimate, "env");
  const next = index.project([assistant, { role: "user", content: "next", timestamp: 12 }], {
    environmentHash: "env",
    environmentTokens: 50,
    contextWindow: 100_000,
  });
  assert.equal(next.confidence, "usage-backed");
  assert.ok(next.effectiveTokens >= 1_000);
  assert.ok(next.effectiveTokens < 1_100);
});