@activefs/testing

Install @activefs/testing in tests that need an in-memory tree, generated fixtures, or the shared ActiveFSTree conformance suite. Do not use its fixture trees as application storage.

The package requires Node.js 22 or newer. The ./conformance entrypoint has a Vitest peer dependency.

Install

npm install @activefs/core
npm install -D @activefs/testing vitest

Use an in-memory fixture

import { createActiveFS } from "@activefs/core";
import { createMemoryTree } from "@activefs/testing";

const tree = createMemoryTree({
  "/hello.md": "# Hello\n",
  "/notes/todo.txt": "ship it\n"
});
const activefs = createActiveFS().mount("/", tree);

const result = await activefs.read({}, "/hello.md");
console.log(result.content);

Output:

# Hello

createMemoryTree can opt into search, mutation, range-read, and watch behavior for tests. Create a new tree per test when mutations are enabled.

Register the conformance suite

The ./conformance entrypoint registers Vitest tests for any tree implementation:

import { createMemoryTree } from "@activefs/testing";
import { runActiveFSTreeConformance } from "@activefs/testing/conformance";

runActiveFSTreeConformance("my tree", () => createMemoryTree({
  files: { "/hello.txt": "hello\n" },
  searchable: true
}), {
  filePath: "/hello.txt",
  expectedContent: "hello",
  searchPattern: "hello"
});

Save this in a Vitest test file. Replace the memory-tree factory with your own isolated tree factory, then add optional write and context assertions when your tree supports those behaviors.

Documentation

• Test and validate a source
• ActiveFSTree authoring
• Example gallery