diff --git a/tests/scenarios/helpers.ts b/tests/scenarios/helpers.ts
index e8af6adba..82d4b232f 100644
--- a/tests/scenarios/helpers.ts
+++ b/tests/scenarios/helpers.ts
@@ -1,66 +1 @@
-import { PreparedApp } from 'scenario-tester';
-import { join } from 'path';
-import { readFileSync } from 'fs';
-import globby from 'globby';
-import { set } from 'lodash';
-import type { JSDOM } from 'jsdom';
-
-export interface FastbootTestHelpers {
-  visit(url: string): Promise<JSDOM>;
-  fetchAsset(url: string): Promise<string>;
-}
-
-export async function setupFastboot(
-  app: PreparedApp,
-  environment = 'development',
-  envVars?: Record<string, string>
-): Promise<FastbootTestHelpers> {
-  let result = await app.execute(`node node_modules/ember-cli/bin/ember build --environment=${environment}`, {
-    env: envVars,
-  });
-
-  if (result.exitCode !== 0) {
-    throw new Error(`failed to build app for fastboot: ${result.output}`);
-  }
-
-  const FastBoot = require('fastboot');
-
-  let fastboot = new FastBoot({
-    distPath: join(app.dir, 'dist'),
-    resilient: false,
-  });
-
-  async function visit(url: string) {
-    const jsdom = require('jsdom');
-    const { JSDOM } = jsdom;
-    let visitOpts = {
-      request: { headers: { host: 'localhost:4200' } },
-    };
-    let page = await fastboot.visit(url, visitOpts);
-    let html = await page.html();
-    return new JSDOM(html);
-  }
-
-  async function fetchAsset(url: string): Promise<string> {
-    const origin = 'http://example.com';
-    let u = new URL(url, origin);
-    if (u.origin !== origin) {
-      throw new Error(`fetchAsset only supports local assets, you asked for ${url}`);
-    }
-    return readFileSync(join(app.dir, 'dist', u.pathname), 'utf-8');
-  }
-
-  return { visit, fetchAsset };
-}
-
-export function loadFromFixtureData(fixtureNamespace: string) {
-  const root = join(__dirname, '..', 'fixtures', fixtureNamespace);
-  const paths = globby.sync('**', { cwd: root, dot: true });
-  const fixtureStructure: any = {};
-
-  paths.forEach(path => {
-    set(fixtureStructure, path.split('/'), readFileSync(join(root, path), 'utf8'));
-  });
-
-  return fixtureStructure;
-}
+export * from './helpers/index';
diff --git a/tests/scenarios/helpers/fastboot.ts b/tests/scenarios/helpers/fastboot.ts
new file mode 100644
index 000000000..bcb777d6e
--- /dev/null
+++ b/tests/scenarios/helpers/fastboot.ts
@@ -0,0 +1,52 @@
+import { PreparedApp } from 'scenario-tester';
+import { join } from 'path';
+import { readFileSync } from 'fs';
+import type { JSDOM } from 'jsdom';
+
+export interface FastbootTestHelpers {
+  visit(url: string): Promise<JSDOM>;
+  fetchAsset(url: string): Promise<string>;
+}
+
+export async function setupFastboot(
+  app: PreparedApp,
+  environment = 'development',
+  envVars?: Record<string, string>
+): Promise<FastbootTestHelpers> {
+  let result = await app.execute(`node node_modules/ember-cli/bin/ember build --environment=${environment}`, {
+    env: envVars,
+  });
+
+  if (result.exitCode !== 0) {
+    throw new Error(`failed to build app for fastboot: ${result.output}`);
+  }
+
+  const FastBoot = require('fastboot');
+
+  let fastboot = new FastBoot({
+    distPath: join(app.dir, 'dist'),
+    resilient: false,
+  });
+
+  async function visit(url: string) {
+    const jsdom = require('jsdom');
+    const { JSDOM } = jsdom;
+    let visitOpts = {
+      request: { headers: { host: 'localhost:4200' } },
+    };
+    let page = await fastboot.visit(url, visitOpts);
+    let html = await page.html();
+    return new JSDOM(html);
+  }
+
+  async function fetchAsset(url: string): Promise<string> {
+    const origin = 'http://example.com';
+    let u = new URL(url, origin);
+    if (u.origin !== origin) {
+      throw new Error(`fetchAsset only supports local assets, you asked for ${url}`);
+    }
+    return readFileSync(join(app.dir, 'dist', u.pathname), 'utf-8');
+  }
+
+  return { visit, fetchAsset };
+}
diff --git a/tests/scenarios/helpers/filesystem.ts b/tests/scenarios/helpers/filesystem.ts
new file mode 100644
index 000000000..5d940ee80
--- /dev/null
+++ b/tests/scenarios/helpers/filesystem.ts
@@ -0,0 +1,45 @@
+import fs from 'fs/promises';
+
+export async function becomesModified({
+  filePath,
+  assert,
+  fn,
+}: {
+  filePath: string;
+  assert: Assert;
+  fn: () => Promise<void>;
+}) {
+  let oldStat = (await fs.stat(filePath)).mtimeMs;
+
+  await fn();
+
+  let newStat = (await fs.stat(filePath)).mtimeMs;
+
+  assert.notStrictEqual(
+    oldStat,
+    newStat,
+    `Expected ${filePath} to be modified. Latest: ${newStat}, previously: ${oldStat}`
+  );
+}
+
+export async function isNotModified({
+  filePath,
+  assert,
+  fn,
+}: {
+  filePath: string;
+  assert: Assert;
+  fn: () => Promise<void>;
+}) {
+  let oldStat = (await fs.stat(filePath)).mtimeMs;
+
+  await fn();
+
+  let newStat = (await fs.stat(filePath)).mtimeMs;
+
+  assert.strictEqual(
+    oldStat,
+    newStat,
+    `Expected ${filePath} to be unchanged. Latest: ${newStat}, and pre-fn: ${oldStat}`
+  );
+}
diff --git a/tests/scenarios/helpers/fixtures.ts b/tests/scenarios/helpers/fixtures.ts
new file mode 100644
index 000000000..d4549d72e
--- /dev/null
+++ b/tests/scenarios/helpers/fixtures.ts
@@ -0,0 +1,16 @@
+import { join } from 'path';
+import { readFileSync } from 'fs';
+import globby from 'globby';
+import { set } from 'lodash';
+
+export function loadFromFixtureData(fixtureNamespace: string) {
+  const root = join(__dirname, '..', '..', 'fixtures', fixtureNamespace);
+  const paths = globby.sync('**', { cwd: root, dot: true });
+  const fixtureStructure: any = {};
+
+  paths.forEach(path => {
+    set(fixtureStructure, path.split('/'), readFileSync(join(root, path), 'utf8'));
+  });
+
+  return fixtureStructure;
+}
diff --git a/tests/scenarios/helpers/index.ts b/tests/scenarios/helpers/index.ts
new file mode 100644
index 000000000..e84f6c706
--- /dev/null
+++ b/tests/scenarios/helpers/index.ts
@@ -0,0 +1,4 @@
+export * from './fastboot';
+export * from './fixtures';
+export * from './v2-addon';
+export * from './filesystem';
diff --git a/tests/scenarios/helpers/v2-addon.ts b/tests/scenarios/helpers/v2-addon.ts
new file mode 100644
index 000000000..9197658b8
--- /dev/null
+++ b/tests/scenarios/helpers/v2-addon.ts
@@ -0,0 +1,91 @@
+import { PreparedApp } from 'scenario-tester';
+import { spawn } from 'child_process';
+
+export class DevWatcher {
+  #addon: PreparedApp;
+  #singletonAbort?: AbortController;
+  #waitForBuildPromise?: Promise<unknown>;
+  #lastBuild?: string;
+
+  constructor(addon: PreparedApp) {
+    this.#addon = addon;
+  }
+
+  start = () => {
+    if (this.#singletonAbort) this.#singletonAbort.abort();
+
+    this.#singletonAbort = new AbortController();
+
+    /**
+     * NOTE: when running rollup in a non-TTY environemnt, the "watching for changes" message does not print.
+     */
+    let rollupProcess = spawn('pnpm', ['start'], {
+      cwd: this.#addon.dir,
+      signal: this.#singletonAbort.signal,
+      stdio: ['pipe', 'pipe', 'pipe'],
+      // Have to disable color so our regex / string matching works easier
+      // Have to include process.env, so the spawned environment has access to `pnpm`
+      env: { ...process.env, NO_COLOR: '1' },
+    });
+
+    let settle: (...args: unknown[]) => void;
+    let error: (...args: unknown[]) => void;
+    this.#waitForBuildPromise = new Promise((resolve, reject) => {
+      settle = resolve;
+      error = reject;
+    });
+
+    if (!rollupProcess.stdout) {
+      throw new Error(`Failed to start process, pnpm start`);
+    }
+    if (!rollupProcess.stderr) {
+      throw new Error(`Failed to start process, pnpm start`);
+    }
+
+    let handleData = (data: Buffer) => {
+      let string = data.toString();
+      let lines = string.split('\n');
+
+      let build = lines.find(line => line.trim().match(/^created dist in (.+)$/));
+      let problem = lines.find(line => line.includes('Error:'));
+      let isAbort = lines.find(line => line.includes('AbortError:'));
+
+      if (isAbort) {
+        // Test may have ended, we want to kill the watcher,
+        // but not error, because throwing an error causes the test to fail.
+        return settle();
+      }
+
+      if (problem) {
+        console.error('\n!!!\n', problem, '\n!!!\n');
+        error(problem);
+        return;
+      }
+
+      if (build) {
+        this.#lastBuild = build[1];
+
+        settle?.();
+
+        this.#waitForBuildPromise = new Promise((resolve, reject) => {
+          settle = resolve;
+          error = reject;
+        });
+      }
+    };
+
+    // NOTE: rollup outputs to stderr only, not stdout
+    rollupProcess.stderr.on('data', (...args) => handleData(...args));
+    rollupProcess.on('error', handleData);
+    rollupProcess.on('close', () => settle?.());
+    rollupProcess.on('exit', () => settle?.());
+
+    return this.#waitForBuildPromise;
+  };
+
+  stop = () => this.#singletonAbort?.abort();
+  settled = () => this.#waitForBuildPromise;
+  get lastBuild() {
+    return this.#lastBuild;
+  }
+}