diff --git a/packages/core/src/check/progress.test.ts b/packages/core/src/check/progress.test.ts
index 769a77e..bd21e55 100644
--- a/packages/core/src/check/progress.test.ts
+++ b/packages/core/src/check/progress.test.ts
@@ -1,7 +1,9 @@
 import { execFileSync } from 'node:child_process';
-import { resolve } from 'node:path';
+import { mkdirSync, mkdtempSync, rmSync } from 'node:fs';
+import { createRequire } from 'node:module';
+import { dirname, join, resolve } from 'node:path';
 import { pathToFileURL } from 'node:url';
-import { expect, it } from 'vitest';
+import { afterAll, expect, it } from 'vitest';
 import { type ProgressEvent, progress } from '../domain/progress.js';
 
 it('pairs progress events even when a phase fails', async () => {
@@ -18,8 +20,23 @@ it('pairs progress events even when a phase fails', async () => {
   expect(events.map((e) => e.state)).toEqual(['start', 'done']);
   expect(events[1]?.ms).toBeGreaterThanOrEqual(0);
 });
+// The built worker (dist/worker.js), not the source one the rest of the suite runs. Built into
+// a private directory: `pnpm build` cleans and rewrites dist/, so a build running alongside
+// (turbo, an editor, a second terminal) could delete the bundle mid-import (#58). Inside
+// node_modules so the bundle's bare imports still resolve from the package.
+const pkg = resolve(import.meta.dirname, '../..');
+mkdirSync(join(pkg, 'node_modules'), { recursive: true });
+const privateDist = mkdtempSync(join(pkg, 'node_modules/.uptide-progress-test-'));
+afterAll(() => rmSync(privateDist, { recursive: true, force: true }));
 it('forwards real workspace worker events without serializing the callback', () => {
-  const entry = pathToFileURL(resolve(import.meta.dirname, '../../dist/index.js')).href;
+  const tsup = join(
+    dirname(createRequire(import.meta.url).resolve('tsup/package.json')),
+    'dist/cli-default.js',
+  );
+  execFileSync(process.execPath, [tsup, '--no-dts', '--no-sourcemap', '--out-dir', privateDist], {
+    cwd: pkg,
+  });
+  const entry = pathToFileURL(join(privateDist, 'index.js')).href;
   const cwd = resolve(import.meta.dirname, '../../../../fixtures/repos/workspace-consumer');
   const output = execFileSync(
     process.execPath,