diff --git a/packages/plugin-notches/CHANGELOG.md b/packages/plugin-notches/CHANGELOG.md
index 4d6ac31b8b6..72796b69f99 100644
--- a/packages/plugin-notches/CHANGELOG.md
+++ b/packages/plugin-notches/CHANGELOG.md
@@ -1,6 +1,12 @@
 # Change log for: @freesewing/plugin-notches
 
 
+## unreleased (NaN-NaN-NaN)
+
+### Added
+
+ - Added (esm) unit tests
+
 ## 2.11.0 (2021-01-10)
 
 ### Added
diff --git a/packages/plugin-notches/package.json b/packages/plugin-notches/package.json
index ee17e471d20..8f3051f4945 100644
--- a/packages/plugin-notches/package.json
+++ b/packages/plugin-notches/package.json
@@ -30,18 +30,23 @@
     "clean": "rimraf dist",
     "build": "rollup -c",
     "lernabuild": "rollup -c",
-    "test": "BABEL_ENV=production ../../node_modules/.bin/_mocha tests/*.test.js --require @babel/register",
+    "test": "BABEL_ENV=production ../../node_modules/.bin/_mocha tests/*.test.mjs --require @babel/register",
     "pubtest": "npm publish --registry http://localhost:6662",
     "pubforce": "npm publish",
     "symlink": "mkdir -p ./node_modules/@freesewing && cd ./node_modules/@freesewing && ln -s -f ../../../* . && cd -",
     "start": "rollup -c -w",
-    "prettier": "npx prettier --write 'src/*.js' 'tests/*.js'"
+    "testci": "BABEL_ENV=production ../../node_modules/.bin/_mocha tests/*.test.mjs --require @babel/register",
+    "prettier": "npx prettier --write 'src/*.js' 'tests/*.mjs'"
   },
   "peerDependencies": {
     "@freesewing/core": "^2.19.5"
   },
   "dependencies": {},
-  "devDependencies": {},
+  "devDependencies": {
+    "mocha": "^9.1.1",
+    "chai": "^4.2.0",
+    "@babel/register": "^7.10.5"
+  },
   "files": [
     "dist/*",
     "README.md",
diff --git a/packages/plugin-notches/src/index.js b/packages/plugin-notches/src/index.js
index 05fbb6762be..fa47ed06c8c 100644
--- a/packages/plugin-notches/src/index.js
+++ b/packages/plugin-notches/src/index.js
@@ -10,7 +10,7 @@ export default {
     preRender: function (svg) {
       if (svg.attributes.get('freesewing:plugin-notches') === false) {
         svg.defs += notches
-        svg.attributes.add('freesewing:plugin-notches', version)
+        svg.attributes.set('freesewing:plugin-notches', version)
       }
     },
   },
diff --git a/packages/plugin-notches/tests/plugin.test.mjs b/packages/plugin-notches/tests/plugin.test.mjs
new file mode 100644
index 00000000000..475b4d8bd22
--- /dev/null
+++ b/packages/plugin-notches/tests/plugin.test.mjs
@@ -0,0 +1,15 @@
+import chai from 'chai'
+import freesewing from '@freesewing/core'
+import plugin from '../dist/index.mjs'
+
+const expect = chai.expect
+
+const pattern = new freesewing.Pattern().use(plugin)
+pattern.draft().render()
+
+describe('Notches Plugin Test', () => {
+  it(`Should add the snippets to defs`, () => {
+    expect(pattern.svg.defs).to.contain('<g id="notch">')
+  })
+})
+
diff --git a/packages/plugin-notches/tests/shared.test.mjs b/packages/plugin-notches/tests/shared.test.mjs
new file mode 100644
index 00000000000..42cd98f4655
--- /dev/null
+++ b/packages/plugin-notches/tests/shared.test.mjs
@@ -0,0 +1,10 @@
+// This file is auto-generated.
+// Changes you make will be overwritten.
+import freesewing from '@freesewing/core'
+import chai from 'chai'
+import plugin from '../dist/index.mjs'
+import { sharedPluginTests } from '../../../tests/plugins/shared.mjs'
+
+
+// Run shared tests
+sharedPluginTests(plugin, freesewing, chai.expect)