diff --git a/tests/helpers/bundle.mjs b/tests/helpers/bundle.mjs
new file mode 100644
index 0000000..273faf8
--- /dev/null
+++ b/tests/helpers/bundle.mjs
@@ -0,0 +1,55 @@
+// Shared test-harness bundler.
+//
+// Every run-*-test.mjs used to hand-roll the same esbuild boilerplate:
+//   write temp entry (optional) -> esbuild.build(bundle/node/esm/silent)
+//   -> dynamic import of the artifact -> rmSync cleanup.
+// This module is that sequence, parameterized. Harnesses call it once (or
+// more, like the chapters harness's three bundles) and get back the loaded
+// module plus a scoped cleanup function.
+import esbuild from "esbuild";
+import fs from "fs";
+import os from "os";
+import path from "path";
+import url from "url";
+
+export async function bundleForTest({
+  // Unique-ish name; also names the temp artifacts (and the generated entry
+  // file when entrySource is used).
+  name,
+  // Module paths to bundle directly (relative to the project root or absolute).
+  entryPoints,
+  // Alternative to entryPoints: inline TS re-export text, written to a temp
+  // entry file next to the project root (deleted right after the build).
+  entrySource,
+  format = "esm",
+  external = [],
+} = {}) {
+  const ext = format === "cjs" ? "cjs" : "mjs";
+  const out = path.join(os.tmpdir(), `${name}-${process.pid}.${ext}`);
+  let tempEntry = null;
+  let eps = entryPoints ?? [];
+  if (entrySource !== undefined) {
+    tempEntry = path.resolve(`.${name}-entry.ts`);
+    fs.writeFileSync(tempEntry, entrySource);
+    eps = [tempEntry];
+  }
+  await esbuild.build({
+    entryPoints: eps.map((p) => path.resolve(p)),
+    bundle: true,
+    platform: "node",
+    format,
+    outfile: out,
+    external,
+    write: true,
+    logLevel: "silent",
+  });
+  if (tempEntry) fs.rmSync(tempEntry, { force: true });
+  const mod = await import(url.pathToFileURL(out).href);
+  return {
+    mod,
+    // Removes only this call's bundled artifact.
+    cleanupBundle() {
+      fs.rmSync(out, { force: true });
+    },
+  };
+}
diff --git a/tests/run-chapters-test.mjs b/tests/run-chapters-test.mjs
index c5dfe6d..01f439c 100644
--- a/tests/run-chapters-test.mjs
+++ b/tests/run-chapters-test.mjs
@@ -1,34 +1,18 @@
 // Standalone test for chapter CRUD logic.
 // Run with: node tests/run-chapters-test.mjs
-import esbuild from "esbuild";
 import fs from "fs";
 import os from "os";
 import path from "path";
-import url from "url";
+import { bundleForTest } from "./helpers/bundle.mjs";
 
-const projOut = path.join(os.tmpdir(), `folio-project-${process.pid}.mjs`);
-const chapOut = path.join(os.tmpdir(), `folio-chapters-${process.pid}.mjs`);
-await esbuild.build({
-  entryPoints: [path.resolve("src/main/project.ts")],
-  bundle: true,
-  platform: "node",
-  format: "esm",
-  outfile: projOut,
-  write: true,
-  logLevel: "silent",
+const { mod: project, cleanupBundle: cleanupProj } = await bundleForTest({
+  name: "folio-project",
+  entryPoints: ["src/main/project.ts"],
 });
-await esbuild.build({
-  entryPoints: [path.resolve("src/main/chapters.ts")],
-  bundle: true,
-  platform: "node",
-  format: "esm",
-  outfile: chapOut,
-  write: true,
-  logLevel: "silent",
+const { mod: chapters, cleanupBundle: cleanupChap } = await bundleForTest({
+  name: "folio-chapters",
+  entryPoints: ["src/main/chapters.ts"],
 });
-
-const project = await import(url.pathToFileURL(projOut).href);
-const chapters = await import(url.pathToFileURL(chapOut).href);
 const { createBook, loadBook, saveMeta, hasBook } = project;
 const {
   listChaptersInOrder,
@@ -145,18 +129,12 @@ ok(JSON.stringify(moveInOrder(["a", "b", "c", "d"], 3, 0)) === JSON.stringify(["
 ok(JSON.stringify(moveInOrder(["a", "b", "c", "d"], 1, 1)) === JSON.stringify(["a", "b", "c", "d"]), "no-op on same index");
 
 // ---- export (combineMarkdown + buildZip) ----
-const exportOut = path.join(os.tmpdir(), `folio-export-${process.pid}.cjs`);
-await esbuild.build({
-  entryPoints: [path.resolve("src/main/export.ts")],
-  bundle: true,
-  platform: "node",
+const { mod: exportMod, cleanupBundle: cleanupExport } = await bundleForTest({
+  name: "folio-export",
+  entryPoints: ["src/main/export.ts"],
   format: "cjs",
-  outfile: exportOut,
-  write: true,
-  logLevel: "silent",
 });
-const exportMod = (await import(url.pathToFileURL(exportOut).href)).default;
-const { combineMarkdown, buildZip } = exportMod;
+const { combineMarkdown, buildZip } = exportMod.default;
 
 const b1 = createChapter(dir, "Intro");
 setChapterContent(dir, b1.id, "# Intro\n\nHello world\n\n- a\n- b");
@@ -177,10 +155,10 @@ ok(zip.includes("title_page.md"), "zip contains title_page.md");
 ok(zip.includes("manifest.json"), "zip contains manifest.json");
 ok(zip.includes("chapters"), "zip contains a chapters/ folder");
 ok(zip.slice(0, 2).toString("ascii") === "PK", "zip starts with PK signature");
-fs.rmSync(exportOut, { force: true });
+cleanupExport();
 
-fs.rmSync(projOut, { force: true });
-fs.rmSync(chapOut, { force: true });
+cleanupProj();
+cleanupChap();
 fs.rmSync(dir, { recursive: true, force: true });
 
 console.log("\nChapter tests: " + (failures === 0 ? "ALL PASSED" : failures + " FAILED"));
diff --git a/tests/run-editor-test.mjs b/tests/run-editor-test.mjs
index 4d6e410..148c67e 100644
--- a/tests/run-editor-test.mjs
+++ b/tests/run-editor-test.mjs
@@ -1,11 +1,10 @@
 // Runner for the Tiptap editor test. Sets up a jsdom DOM, then dynamically
 // imports the bundled editor module so Tiptap sees a browser-like environment.
-import esbuild from "esbuild";
 import fs from "fs";
 import os from "os";
 import path from "path";
-import url from "url";
 import { JSDOM } from "jsdom";
+import { bundleForTest } from "./helpers/bundle.mjs";
 
 const dom = new JSDOM("<!DOCTYPE html><html><body></body></html>", {
   pretendToBeVisual: true,
@@ -24,19 +23,10 @@ g.DOMParser = window.DOMParser;
 g.requestAnimationFrame = (cb) => setTimeout(cb, 0);
 g.cancelAnimationFrame = (id) => clearTimeout(id);
 
-const out = path.join(os.tmpdir(), `folio-editor-${process.pid}.mjs`);
-const entry = path.resolve("tests/.folio-editor-test-entry.ts");
-await esbuild.build({
-  entryPoints: [entry],
-  bundle: true,
-  platform: "node",
-  format: "esm",
-  outfile: out,
-  write: true,
-  logLevel: "silent",
+const { mod, cleanupBundle } = await bundleForTest({
+  name: "folio-editor",
+  entryPoints: ["tests/.folio-editor-test-entry.ts"],
 });
-
-const mod = await import(url.pathToFileURL(out).href);
 const {
   createTiptapEditor,
   runCommand,
@@ -235,7 +225,7 @@ ok(
   "standalone Highlight button applies a default highlight to the selection"
 );
 
-fs.rmSync(out, { force: true });
+cleanupBundle();
 fs.rmSync(book, { recursive: true, force: true });
 
 console.log(
diff --git a/tests/run-fullbook-test.mjs b/tests/run-fullbook-test.mjs
index 205182d..3a92406 100644
--- a/tests/run-fullbook-test.mjs
+++ b/tests/run-fullbook-test.mjs
@@ -2,12 +2,10 @@
 // renderer assembly + Tiptap modules, and verifies that a book assembled from
 // native chapters renders with correct chapter order, page-break anchors,
 // reorder behavior, title injection, and Copy-All native fidelity.
-import esbuild from "esbuild";
 import fs from "fs";
-import os from "os";
 import path from "path";
-import url from "url";
 import { JSDOM } from "jsdom";
+import { bundleForTest } from "./helpers/bundle.mjs";
 
 const dom = new JSDOM("<!DOCTYPE html><html><body></body></html>", {
   pretendToBeVisual: true,
@@ -26,19 +24,10 @@ g.DOMParser = window.DOMParser;
 g.requestAnimationFrame = (cb) => setTimeout(cb, 0);
 g.cancelAnimationFrame = (id) => clearTimeout(id);
 
-const out = path.join(os.tmpdir(), `folio-fullbook-${process.pid}.mjs`);
-const entry = path.resolve("tests/.folio-fullbook-test-entry.ts");
-await esbuild.build({
-  entryPoints: [entry],
-  bundle: true,
-  platform: "node",
-  format: "esm",
-  outfile: out,
-  write: true,
-  logLevel: "silent",
+const { mod, cleanupBundle } = await bundleForTest({
+  name: "folio-fullbook",
+  entryPoints: ["tests/.folio-fullbook-test-entry.ts"],
 });
-
-const mod = await import(url.pathToFileURL(out).href);
 const {
   buildFullBookDoc,
   nativeNodeText,
@@ -190,6 +179,6 @@ ok(
   "empty book assembles to empty doc"
 );
 
-fs.rmSync(out, { force: true });
+cleanupBundle();
 console.log("\nFull Book tests: " + (failures === 0 ? "ALL PASSED" : failures + " FAILED"));
 process.exit(failures === 0 ? 0 : 1);
diff --git a/tests/run-migration-test.mjs b/tests/run-migration-test.mjs
index 10f4b71..bb458f8 100644
--- a/tests/run-migration-test.mjs
+++ b/tests/run-migration-test.mjs
@@ -8,37 +8,22 @@
 //   - idempotency (original .md untouched)
 // Builds src/main/migration.ts with esbuild (no Electron needed).
 // Run with: node tests/run-migration-test.mjs
-import esbuild from "esbuild";
 import fs from "fs";
 import os from "os";
 import path from "path";
-import url from "url";
+import { bundleForTest } from "./helpers/bundle.mjs";
 
-const out = path.join(os.tmpdir(), `folio-migration-${process.pid}.mjs`);
-const entry = path.resolve(".folio-mig-test-entry.ts");
-fs.writeFileSync(
-  entry,
-  `
+const { mod, cleanupBundle } = await bundleForTest({
+  name: "folio-migration",
+  entrySource: `
 export { migrateChapterToNative, migrateBookToNative, isNativeChapter } from "./src/main/migration.ts";
 export { createBook, loadBook, saveMeta } from "./src/main/project.ts";
 export { setChapterContent, getChapterContent } from "./src/main/chapters.ts";
 export { markdownToNative } from "./src/main/markdown-to-native.ts";
 export { parseChapter, serializeChapter, migrateDoc, getChapterDoc, nativeChapterFile, CURRENT_DOC_SCHEMA_VERSION, isValidDoc } from "./src/main/native-doc.ts";
 export { getRecoveryRoot, _resetSessionBackupGuard } from "./src/main/backup.ts";
-`
-);
-await esbuild.build({
-  entryPoints: [entry],
-  bundle: true,
-  platform: "node",
-  format: "esm",
-  outfile: out,
-  write: true,
-  logLevel: "silent",
+`,
 });
-fs.rmSync(entry, { force: true });
-
-const mod = await import(url.pathToFileURL(out).href);
 const {
   createBook,
   setChapterContent,
@@ -291,7 +276,7 @@ ok(
 // ---------------------------------------------------------------------------
 // Cleanup
 // ---------------------------------------------------------------------------
-fs.rmSync(out, { force: true });
+cleanupBundle();
 fs.rmSync(book, { recursive: true, force: true });
 for (const d of backups) {
   fs.rmSync(path.join(getRecoveryRoot(), d), { recursive: true, force: true });
diff --git a/tests/run-office-export-test.mjs b/tests/run-office-export-test.mjs
index 1669c71..d72bf99 100644
--- a/tests/run-office-export-test.mjs
+++ b/tests/run-office-export-test.mjs
@@ -4,27 +4,18 @@
 // JSON, then inspects the produced ZIP contents to check that the manuscript,
 // its chapter order, and its formatting survive the native -> DOCX path.
 // Run with: node tests/run-office-export-test.mjs
-import esbuild from "esbuild";
 import fs from "fs";
 import os from "os";
 import path from "path";
-import url from "url";
 import JSZip from "jszip";
+import { bundleForTest } from "./helpers/bundle.mjs";
 
-const out = path.resolve(`tests/.tmp-folio-office-${process.pid}.mjs`);
-await esbuild.build({
-  entryPoints: [path.resolve("src/main/office-export.ts")],
-  bundle: true,
-  platform: "node",
-  format: "esm",
+const { mod, cleanupBundle } = await bundleForTest({
+  name: "folio-office",
+  entryPoints: ["src/main/office-export.ts"],
   external: ["electron"],
-  outfile: out,
-  write: true,
-  logLevel: "silent",
 });
 
-const mod = await import(url.pathToFileURL(out).href);
-
 let failures = 0;
 const check = (name, ok) => {
   console.log(`${ok ? "PASS" : "FAIL"} ${name}`);
@@ -271,7 +262,7 @@ for (const [f, bytes] of origFiles) {
 check("folio.json unchanged", fs.readFileSync(path.join(bookDir, "folio.json")).equals(origManifest));
 
 fs.rmSync(bookDir, { recursive: true, force: true });
-fs.rmSync(out, { force: true });
+cleanupBundle();
 
 if (odtSkipped) {
   console.log("NOTE ODT verification requires LibreOffice; it was skipped.");
diff --git a/tests/run-print-test.mjs b/tests/run-print-test.mjs
index fca7100..d46d098 100644
--- a/tests/run-print-test.mjs
+++ b/tests/run-print-test.mjs
@@ -3,25 +3,14 @@
 // renderer module and verifies that chapter breaks become print sections and
 // that every rich-text feature survives the native -> HTML conversion.
 // Run with: node tests/run-print-test.mjs
-import esbuild from "esbuild";
 import fs from "fs";
-import os from "os";
-import path from "path";
-import url from "url";
+import { bundleForTest } from "./helpers/bundle.mjs";
 
-const out = path.resolve(`tests/.tmp-folio-print-${process.pid}.mjs`);
-await esbuild.build({
-  entryPoints: [path.resolve("src/renderer/print-format.ts")],
-  bundle: true,
-  platform: "node",
-  format: "esm",
+const { mod, cleanupBundle } = await bundleForTest({
+  name: "folio-print",
+  entryPoints: ["src/renderer/print-format.ts"],
   external: ["electron"],
-  outfile: out,
-  write: true,
-  logLevel: "silent",
 });
-
-const mod = await import(url.pathToFileURL(out).href);
 const renderPrintChaptersNative = mod.renderPrintChaptersNative;
 
 let failures = 0;
@@ -136,7 +125,7 @@ check("renders external link", /<a href="https:\/\/example.com">Site<\/a>/.test(
 check("renders wikilink as internal anchor", /<a href="folio:chapter\/Two" class="wikilink internal">Go<\/a>/.test(html));
 check("no raw wikilink brackets", !html.includes("[[Two"));
 
-fs.rmSync(out, { force: true });
+cleanupBundle();
 
 if (failures > 0) {
   console.error(`\n${failures} check(s) failed.`);
diff --git a/tests/run-project-test.mjs b/tests/run-project-test.mjs
index b528763..1ff5a34 100644
--- a/tests/run-project-test.mjs
+++ b/tests/run-project-test.mjs
@@ -1,24 +1,15 @@
 // Standalone test for the pure project/recents logic.
 // Builds src/main/project.ts with esbuild (no Electron needed) and asserts behavior.
 // Run with: node tests/run-project-test.mjs
-import esbuild from "esbuild";
 import fs from "fs";
 import os from "os";
 import path from "path";
-import url from "url";
+import { bundleForTest } from "./helpers/bundle.mjs";
 
-const out = path.join(os.tmpdir(), `folio-project-${process.pid}.mjs`);
-await esbuild.build({
-  entryPoints: [path.resolve("src/main/project.ts")],
-  bundle: true,
-  platform: "node",
-  format: "esm",
-  outfile: out,
-  write: true,
-  logLevel: "silent",
+const { mod, cleanupBundle } = await bundleForTest({
+  name: "folio-project",
+  entryPoints: ["src/main/project.ts"],
 });
-
-const mod = await import(url.pathToFileURL(out).href);
 const {
   APP_ID,
   META_FILE,
@@ -78,7 +69,7 @@ const id = makeChapterId("Chapter One");
 ok(id.startsWith("chapter-one-"), "chapter id slugified: " + id);
 ok(chapterFileName(id) === `${id}.md`, "filename is <id>.md");
 
-fs.rmSync(out, { force: true });
+cleanupBundle();
 fs.rmSync(dir, { recursive: true, force: true });
 
 console.log("\nProject tests: " + (failures === 0 ? "ALL PASSED" : failures + " FAILED"));
diff --git a/tests/run-wikilinks-test.mjs b/tests/run-wikilinks-test.mjs
index a8672af..e480710 100644
--- a/tests/run-wikilinks-test.mjs
+++ b/tests/run-wikilinks-test.mjs
@@ -1,24 +1,13 @@
 // Standalone test for the Obsidian-style wikilink plugin.
 // Run with: node tests/run-wikilinks-test.mjs
-import esbuild from "esbuild";
 import MarkdownIt from "markdown-it";
 import fs from "fs";
-import os from "os";
-import path from "path";
-import url from "url";
+import { bundleForTest } from "./helpers/bundle.mjs";
 
-const out = path.join(os.tmpdir(), `folio-wikilinks-${process.pid}.mjs`);
-await esbuild.build({
-  entryPoints: [path.resolve("src/renderer/wikilinks.ts")],
-  bundle: true,
-  platform: "node",
-  format: "esm",
-  outfile: out,
-  write: true,
-  logLevel: "silent",
+const { mod, cleanupBundle } = await bundleForTest({
+  name: "folio-wikilinks",
+  entryPoints: ["src/renderer/wikilinks.ts"],
 });
-
-const mod = await import(url.pathToFileURL(out).href);
 const { wikilinkPlugin } = mod;
 
 const chapters = [
@@ -101,7 +90,7 @@ ok(!html8.includes('class="wikilink"'), "nested brackets not parsed as wikilink"
 const html9 = md.render("empty [[] here");
 ok(!html9.includes('class="wikilink"'), "empty wikilink target not parsed");
 
-fs.rmSync(out, { force: true });
+cleanupBundle();
 
 console.log("\nWikilink tests: " + (failures === 0 ? "ALL PASSED" : failures + " FAILED"));
 process.exit(failures === 0 ? 0 : 1);