diff --git a/ansible/www-standalone/tools/promote/check_assets.test.mjs b/ansible/www-standalone/tools/promote/check_assets.test.mjs
new file mode 100755
index 000000000..17448df91
--- /dev/null
+++ b/ansible/www-standalone/tools/promote/check_assets.test.mjs
@@ -0,0 +1,96 @@
+import assert from 'node:assert';
+import { execFile } from 'node:child_process';
+import { mkdir, mkdtemp, readFile, rm, writeFile } from 'node:fs/promises';
+import { tmpdir } from 'node:os';
+import { basename, join } from 'node:path';
+import { afterEach, beforeEach, describe, it } from 'node:test';
+
+// execute check_assets.js with the given staging and dist dirs, collect output
+async function executeMe (stagingDir, distDir) {
+  return new Promise((resolve, reject) => {
+    const args = [ '--no-warnings', join(import.meta.dirname, 'check_assets.js'), stagingDir, distDir ];
+    execFile(process.execPath, args, (err, stdout, stderr) => {
+      if (err) {
+        return reject(err);
+      }
+      if (stderr) {
+        console.log('STDERR:', stderr);
+      }
+      resolve(stdout);
+    });
+  });
+}
+
+async function loadExpectedAssets (version, line) {
+  if (!line) {
+    line = versionToLine(version);
+  }
+  try {
+    const templateFile = join(import.meta.dirname, 'expected_assets', line);
+    let files = await readFile(templateFile, 'utf8');
+    return files.replace(/{VERSION}/g, version).split(/\n/g).filter(Boolean);
+  } catch (e) { }
+  return null;
+}
+
+// makes a staging or dist directory given a version string
+async function makeFixture (version, isStaging, dir, assets) {
+  if (!assets) {
+    assets = await loadExpectedAssets(version);
+  }
+  for (let asset of assets) {
+    let absoluteAsset = join(dir, asset);
+    if (asset.endsWith('/')) {
+      await mkdir(absoluteAsset, { recursive: true });
+    } else {
+      await writeFile(absoluteAsset, asset, 'utf8');
+    }
+    let dashPos = isStaging && asset.indexOf('/');
+    if (isStaging && (dashPos === -1 || dashPos === asset.length - 1)) {
+      // in staging, all files and directories that are ready have a
+      // duplicate empty file with .done in the name
+      await writeFile(absoluteAsset.replace(/\/?$/, '.done'), asset, 'utf8');
+    }
+  }
+  return assets;
+}
+
+async function runTest (context, version, expectedStdout, setup) {
+  const fixtureStagingDir = join(context.fixtureStagingDir, version);
+  const fixtureDistDir = join(context.fixtureDistDir, version);
+  await setup(fixtureStagingDir, fixtureDistDir);
+
+  const stdout = await executeMe(fixtureStagingDir, fixtureDistDir);
+  assert.strictEqual(stdout, expectedStdout);
+}
+
+function versionToLine (version) {
+    return version.replace(/^(v\d+)\.[\d.]+.*/g, '$1.x')
+}
+
+describe('tests', async () => {
+  beforeEach(async (context) => {
+    context.testDir = await mkdtemp(join(tmpdir(), `${basename(import.meta.filename)}_`));
+    context.fixtureDistDir = join(context.testDir, 'dist');
+    context.fixtureStagingDir = join(context.testDir, 'staging');
+    await mkdir(context.fixtureDistDir);
+    await mkdir(context.fixtureStagingDir);
+  });
+  afterEach(async (context) => {
+    await rm(context.testDir, { recursive: true, force: true, maxRetries: 10 });
+  });
+  it('Everything is in staging, nothing in dist, good to go', async (context) => {
+    const version = 'v8.13.0';
+    const expectedStdout =
+      '... Checking assets\n' +
+      '... Expecting a total of 44 assets for v8.x\n' +
+      '... 44 assets waiting in staging\n' +
+      '... 0 assets already promoted\n' +
+      ' \u001b[32m\u001b[1m✓\u001b[22m\u001b[39m  Complete set of expected assets in place for v8.x\n';
+    async function setup (fixtureStagingDir, fixtureDistDir) {
+      await makeFixture(version, true, fixtureStagingDir);
+    }
+
+    await runTest(context, version, expectedStdout, setup);
+  });
+});