diff --git a/jest.config.js b/jest.config.js
new file mode 100644
index 0000000..f5d30d1
--- /dev/null
+++ b/jest.config.js
@@ -0,0 +1,7 @@
+/** @type {import('ts-jest').JestConfigWithTsJest} **/
+module.exports = {
+  testEnvironment: "node",
+  transform: {
+    "^.+.tsx?$": ["ts-jest",{}],
+  },
+};
\ No newline at end of file
diff --git a/package.json b/package.json
index 7a73343..9cade39 100644
--- a/package.json
+++ b/package.json
@@ -6,6 +6,7 @@
   },
   "scripts": {
     "build": "npx tsc",
+    "test": "jest",
     "djockey": "npx tsc && node dist/cli.js"
   },
   "dependencies": {
@@ -16,12 +17,15 @@
     "nunjucks": "^3.2.4"
   },
   "devDependencies": {
+    "@jest/globals": "^29.7.0",
     "@types/argparse": "^2.0.16",
+    "@types/jest": "^29.5.12",
     "@types/js-yaml": "^4.0.9",
     "@types/node": "^22.4.0",
     "@types/nunjucks": "^3.2.6",
     "jest": "^29.7.0",
     "sinon": "^18.0.0",
+    "ts-jest": "^29.2.4",
     "typescript": "^5.5.4"
   }
 }
diff --git a/src/plugins/tableOfContentsPlugin.test.ts b/src/plugins/tableOfContentsPlugin.test.ts
new file mode 100644
index 0000000..263158c
--- /dev/null
+++ b/src/plugins/tableOfContentsPlugin.test.ts
@@ -0,0 +1,53 @@
+import { BulletList, parse, renderHTML } from "@djot/djot";
+import { DjockeyDoc } from "../types";
+import { TableOfContentsPlugin, TOCEntry } from "./tableOfContentsPlugin";
+
+test("Generates TOCEntry tree", () => {
+  const doc: DjockeyDoc = {
+    djotDoc: parse(`
+      # Heading 1
+      ## Heading 1.1
+      # Heading 2
+      ### Heading 2.2
+      `),
+    title: "Test doc",
+    originalExtension: ".djot",
+    absolutePath: "Test Doc.djot",
+    relativePath: "Test Doc.djot",
+    filename: "Test Doc",
+    frontMatter: {},
+    data: {},
+  };
+
+  const plg = new TableOfContentsPlugin();
+  plg.onPass_read(doc);
+  plg.onPass_write(doc);
+
+  const html = renderHTML({
+    tag: "doc",
+    references: {},
+    autoReferences: {},
+    footnotes: {},
+    children: [doc.data.toc as BulletList],
+  });
+
+  expect(html).toEqual(`<ul>
+<li>
+Heading 1
+<ul>
+<li>
+Heading 1.1
+</li>
+</ul>
+</li>
+<li>
+Heading 2
+<ul>
+<li>
+Heading 2.2
+</li>
+</ul>
+</li>
+</ul>
+`);
+});
diff --git a/src/plugins/tableOfContentsPlugin.ts b/src/plugins/tableOfContentsPlugin.ts
index 08f00e2..0e995e7 100644
--- a/src/plugins/tableOfContentsPlugin.ts
+++ b/src/plugins/tableOfContentsPlugin.ts
@@ -2,7 +2,7 @@ import { BulletList, Heading, Inline, ListItem } from "@djot/djot";
 import { applyFilter } from "../engine/djotFiltersPlus";
 import { DjockeyDoc, DjockeyPlugin } from "../types";
 
-type TOCEntry = {
+export type TOCEntry = {
   id: string;
   node: Heading;
   children: TOCEntry[];
@@ -59,6 +59,9 @@ export class TableOfContentsPlugin implements DjockeyPlugin {
 
 const renderTOCArray: (arr: TOCEntry[]) => BulletList = (arr) => {
   const tocEntryToListItem = (entry: TOCEntry) => {
+    const entryChildren: BulletList[] = entry.children.length
+      ? [renderTOCArray(entry.children)]
+      : [];
     const result: ListItem = {
       tag: "list_item",
       children: [
@@ -66,7 +69,7 @@ const renderTOCArray: (arr: TOCEntry[]) => BulletList = (arr) => {
           tag: "para",
           children: entry.node.children,
         },
-        renderTOCArray(entry.children),
+        ...entryChildren,
       ],
     };
     return result;
diff --git a/yarn.lock b/yarn.lock
index fa63775..6d1a97c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -920,6 +920,16 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/jest@npm:^29.5.12":
+  version: 29.5.12
+  resolution: "@types/jest@npm:29.5.12"
+  dependencies:
+    expect: ^29.0.0
+    pretty-format: ^29.0.0
+  checksum: 19b1efdeed9d9a60a81edc8226cdeae5af7479e493eaed273e01243891c9651f7b8b4c08fc633a7d0d1d379b091c4179bbaa0807af62542325fd72f2dd17ce1c
+  languageName: node
+  linkType: hard
+
 "@types/js-yaml@npm:^4.0.9":
   version: 4.0.9
   resolution: "@types/js-yaml@npm:4.0.9"
@@ -1087,6 +1097,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"async@npm:^3.2.3":
+  version: 3.2.6
+  resolution: "async@npm:3.2.6"
+  checksum: ee6eb8cd8a0ab1b58bd2a3ed6c415e93e773573a91d31df9d5ef559baafa9dab37d3b096fa7993e84585cac3697b2af6ddb9086f45d3ac8cae821bb2aab65682
+  languageName: node
+  linkType: hard
+
 "babel-jest@npm:^29.7.0":
   version: 29.7.0
   resolution: "babel-jest@npm:29.7.0"
@@ -1215,6 +1232,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"bs-logger@npm:0.x":
+  version: 0.2.6
+  resolution: "bs-logger@npm:0.2.6"
+  dependencies:
+    fast-json-stable-stringify: 2.x
+  checksum: d34bdaf68c64bd099ab97c3ea608c9ae7d3f5faa1178b3f3f345acd94e852e608b2d4f9103fb2e503f5e69780e98293df41691b84be909b41cf5045374d54606
+  languageName: node
+  linkType: hard
+
 "bser@npm:2.1.1":
   version: 2.1.1
   resolution: "bser@npm:2.1.1"
@@ -1290,7 +1316,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"chalk@npm:^4.0.0":
+"chalk@npm:^4.0.0, chalk@npm:^4.0.2":
   version: 4.1.2
   resolution: "chalk@npm:4.1.2"
   dependencies:
@@ -1498,7 +1524,9 @@ __metadata:
   resolution: "djockey@workspace:."
   dependencies:
     "@djot/djot": ^0.3.1
+    "@jest/globals": ^29.7.0
     "@types/argparse": ^2.0.16
+    "@types/jest": ^29.5.12
     "@types/js-yaml": ^4.0.9
     "@types/node": ^22.4.0
     "@types/nunjucks": ^3.2.6
@@ -1508,6 +1536,7 @@ __metadata:
     js-yaml: ^4.1.0
     nunjucks: ^3.2.4
     sinon: ^18.0.0
+    ts-jest: ^29.2.4
     typescript: ^5.5.4
   languageName: unknown
   linkType: soft
@@ -1519,6 +1548,17 @@ __metadata:
   languageName: node
   linkType: hard
 
+"ejs@npm:^3.1.10":
+  version: 3.1.10
+  resolution: "ejs@npm:3.1.10"
+  dependencies:
+    jake: ^10.8.5
+  bin:
+    ejs: bin/cli.js
+  checksum: ce90637e9c7538663ae023b8a7a380b2ef7cc4096de70be85abf5a3b9641912dde65353211d05e24d56b1f242d71185c6d00e02cb8860701d571786d92c71f05
+  languageName: node
+  linkType: hard
+
 "electron-to-chromium@npm:^1.5.4":
   version: 1.5.11
   resolution: "electron-to-chromium@npm:1.5.11"
@@ -1634,7 +1674,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"expect@npm:^29.7.0":
+"expect@npm:^29.0.0, expect@npm:^29.7.0":
   version: 29.7.0
   resolution: "expect@npm:29.7.0"
   dependencies:
@@ -1667,7 +1707,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"fast-json-stable-stringify@npm:^2.1.0":
+"fast-json-stable-stringify@npm:2.x, fast-json-stable-stringify@npm:^2.1.0":
   version: 2.1.0
   resolution: "fast-json-stable-stringify@npm:2.1.0"
   checksum: b191531e36c607977e5b1c47811158733c34ccb3bfde92c44798929e9b4154884378536d26ad90dfecd32e1ffc09c545d23535ad91b3161a27ddbb8ebe0cbecb
@@ -1692,6 +1732,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"filelist@npm:^1.0.4":
+  version: 1.0.4
+  resolution: "filelist@npm:1.0.4"
+  dependencies:
+    minimatch: ^5.0.1
+  checksum: a303573b0821e17f2d5e9783688ab6fbfce5d52aaac842790ae85e704a6f5e4e3538660a63183d6453834dedf1e0f19a9dadcebfa3e926c72397694ea11f5160
+  languageName: node
+  linkType: hard
+
 "fill-range@npm:^7.1.1":
   version: 7.1.1
   resolution: "fill-range@npm:7.1.1"
@@ -2138,6 +2187,20 @@ __metadata:
   languageName: node
   linkType: hard
 
+"jake@npm:^10.8.5":
+  version: 10.9.2
+  resolution: "jake@npm:10.9.2"
+  dependencies:
+    async: ^3.2.3
+    chalk: ^4.0.2
+    filelist: ^1.0.4
+    minimatch: ^3.1.2
+  bin:
+    jake: bin/cli.js
+  checksum: f2dc4a086b4f58446d02cb9be913c39710d9ea570218d7681bb861f7eeaecab7b458256c946aeaa7e548c5e0686cc293e6435501e4047174a3b6a504dcbfcaae
+  languageName: node
+  linkType: hard
+
 "jest-changed-files@npm:^29.7.0":
   version: 29.7.0
   resolution: "jest-changed-files@npm:29.7.0"
@@ -2502,7 +2565,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"jest-util@npm:^29.7.0":
+"jest-util@npm:^29.0.0, jest-util@npm:^29.7.0":
   version: 29.7.0
   resolution: "jest-util@npm:29.7.0"
   dependencies:
@@ -2683,6 +2746,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"lodash.memoize@npm:4.x":
+  version: 4.1.2
+  resolution: "lodash.memoize@npm:4.1.2"
+  checksum: 9ff3942feeccffa4f1fafa88d32f0d24fdc62fd15ded5a74a5f950ff5f0c6f61916157246744c620173dddf38d37095a92327d5fd3861e2063e736a5c207d089
+  languageName: node
+  linkType: hard
+
 "lru-cache@npm:^10.0.1, lru-cache@npm:^10.2.0":
   version: 10.4.3
   resolution: "lru-cache@npm:10.4.3"
@@ -2708,6 +2778,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"make-error@npm:1.x":
+  version: 1.3.6
+  resolution: "make-error@npm:1.3.6"
+  checksum: b86e5e0e25f7f777b77fabd8e2cbf15737972869d852a22b7e73c17623928fccb826d8e46b9951501d3f20e51ad74ba8c59ed584f610526a48f8ccf88aaec402
+  languageName: node
+  linkType: hard
+
 "make-fetch-happen@npm:^13.0.0":
   version: 13.0.1
   resolution: "make-fetch-happen@npm:13.0.1"
@@ -2768,7 +2845,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"minimatch@npm:^3.0.4, minimatch@npm:^3.1.1":
+"minimatch@npm:^3.0.4, minimatch@npm:^3.1.1, minimatch@npm:^3.1.2":
   version: 3.1.2
   resolution: "minimatch@npm:3.1.2"
   dependencies:
@@ -2777,6 +2854,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"minimatch@npm:^5.0.1":
+  version: 5.1.6
+  resolution: "minimatch@npm:5.1.6"
+  dependencies:
+    brace-expansion: ^2.0.1
+  checksum: 7564208ef81d7065a370f788d337cd80a689e981042cb9a1d0e6580b6c6a8c9279eba80010516e258835a988363f99f54a6f711a315089b8b42694f5da9d0d77
+  languageName: node
+  linkType: hard
+
 "minimatch@npm:^9.0.4":
   version: 9.0.5
   resolution: "minimatch@npm:9.0.5"
@@ -3147,7 +3233,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"pretty-format@npm:^29.7.0":
+"pretty-format@npm:^29.0.0, pretty-format@npm:^29.7.0":
   version: 29.7.0
   resolution: "pretty-format@npm:29.7.0"
   dependencies:
@@ -3598,6 +3684,43 @@ __metadata:
   languageName: node
   linkType: hard
 
+"ts-jest@npm:^29.2.4":
+  version: 29.2.4
+  resolution: "ts-jest@npm:29.2.4"
+  dependencies:
+    bs-logger: 0.x
+    ejs: ^3.1.10
+    fast-json-stable-stringify: 2.x
+    jest-util: ^29.0.0
+    json5: ^2.2.3
+    lodash.memoize: 4.x
+    make-error: 1.x
+    semver: ^7.5.3
+    yargs-parser: ^21.0.1
+  peerDependencies:
+    "@babel/core": ">=7.0.0-beta.0 <8"
+    "@jest/transform": ^29.0.0
+    "@jest/types": ^29.0.0
+    babel-jest: ^29.0.0
+    jest: ^29.0.0
+    typescript: ">=4.3 <6"
+  peerDependenciesMeta:
+    "@babel/core":
+      optional: true
+    "@jest/transform":
+      optional: true
+    "@jest/types":
+      optional: true
+    babel-jest:
+      optional: true
+    esbuild:
+      optional: true
+  bin:
+    ts-jest: cli.js
+  checksum: 142246f12bb11d5edbfb5a65e298097667e2c4d390e316e356416ce00d3cd157220dbfb9de2a56b38f30776bc92ba59eff9fd78e9345ba4c6712783f27f5475a
+  languageName: node
+  linkType: hard
+
 "type-detect@npm:4.0.8":
   version: 4.0.8
   resolution: "type-detect@npm:4.0.8"
@@ -3780,7 +3903,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"yargs-parser@npm:^21.1.1":
+"yargs-parser@npm:^21.0.1, yargs-parser@npm:^21.1.1":
   version: 21.1.1
   resolution: "yargs-parser@npm:21.1.1"
   checksum: ed2d96a616a9e3e1cc7d204c62ecc61f7aaab633dcbfab2c6df50f7f87b393993fe6640d017759fe112d0cb1e0119f2b4150a87305cc873fd90831c6a58ccf1c