Chroma-t2t

@chroma/t2t — test-to-test utilities for Chroma apps: Node test bridge, snapshot smoke checks, and persist round-trip validation.

Chroma-t2t is the canonical @chroma/t2t plugin: dev and smoke-test helpers for Chroma apps that use chroma-fs persistence.

Plugin folder: chroma-t2t
Package id: @chroma/t2t
Source: workspace Chroma-t2t/ (nested-repo ready, like Chroma-Router/)
License: GNU GPL version 3 (LICENSE in the package root)

When you run chroma install, the plugin is copied into ~/.chroma/plugins/chroma-t2t/ from Chroma-t2t/ when present in the workspace, else from Chroma/cli/plugins/chroma-t2t/. Add "chroma-t2t" to your app's chroma.json plugins array and wire bootstrapT2t in plugins/loader.js.

What it provides

API	Purpose
`bootstrapT2t(options)`	Bootstrap hook — exposes the t2t API and optionally attaches `globalThis.__chromaT2t`
`createTestApi(options)`	Build the API without global attachment
`assertPersistRoundTrip(adapters, options)`	Export → reset → import round-trip through app-provided persist adapters
`smokeSnapshot(snapshot, collectionKeys)`	Assert snapshot collections are arrays
`createPersistRoundTrip(adapters)`	Bind adapters into a reusable round-trip function
`createSnapshotSmoke(getSnapshot, keys)`	Bind snapshot getter + collection keys
`runNodeTests(options)`	Spawn `npm test` (Node-only; returns usage info in the browser)
`runAll()`	Run configured smoke + persist checks (optional Node suite via `includeNodeTests`)

Quick start

import { bootstrapT2t } from "./plugins/chroma-t2t/index.js";

await bootstrapT2t({
  persist: {
    adapters: {
      reset,
      createMemoryStorage,
      hydrate,
      setPersisted,
      flush,
      getSnapshot,
      buildExportPayload,
      serializeExport,
      parseImport,
      validateImport,
      applyImport,
    },
    seed: { settings: { theme: "system" } },
    verify: (snapshot) => {
      if (!snapshot.settings) throw new Error("settings missing after round-trip");
    },
  },
  snapshot: {
    getSnapshot,
    collectionKeys: ["transactions", "categories", "accounts", "budgets"],
  },
});

// In devtools console:
globalThis.__chromaT2t.runAll();

Node test bridge

From a vendored copy inside an app:

node plugins/chroma-t2t/node/run-tests.mjs

The script spawns npm test from the project root (same pattern as the legacy chroma-test plugin).

Loader wiring

if (name === "chroma-t2t") {
  const { bootstrapT2t } = await import("./chroma-t2t/index.js");
  loaded.t2t = await bootstrapT2t({
    persist: { adapters: appPersistAdapters, /* seed, verify */ },
    snapshot: { getSnapshot, collectionKeys: ["items"] },
  });
}

Pass app-specific adapters in main.js — the plugin stays generic and does not import app logic.

Install and sync

Command	Result
`chroma install`	Copies `chroma-t2t` to `~/.chroma/plugins/chroma-t2t/`
`./scripts/sync-chroma-plugins.sh`	Refreshes `Chroma/cli/plugins/chroma-t2t/`, `Chroma-CLI/plugins/chroma-t2t/`, and example templates

Edit Chroma-t2t/, then run ./scripts/sync-chroma-plugins.sh before packaging or committing vendored copies.

Plugin Standard — chroma.plugin.json contract and loader pattern
Extensions & Plugins — built-in plugin table
CLI — chroma install, chroma new