diff --git a/packages/plugin-grainline/CHANGELOG.md b/packages/plugin-grainline/CHANGELOG.md
index 04e76b929ef..cb16a8ab3ac 100644
--- a/packages/plugin-grainline/CHANGELOG.md
+++ b/packages/plugin-grainline/CHANGELOG.md
@@ -1,6 +1,12 @@
 # Change log for: @freesewing/plugin-grainline
 
 
+## unreleased (NaN-NaN-NaN)
+
+### Added
+
+ - Added (esm) unit tests
+
 ## 2.0.0 (2019-08-25)
 
 ### Added
diff --git a/packages/plugin-grainline/package.json b/packages/plugin-grainline/package.json
index a8c6b92ebcc..589ee799123 100644
--- a/packages/plugin-grainline/package.json
+++ b/packages/plugin-grainline/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-grainline/src/index.js b/packages/plugin-grainline/src/index.js
index 13e77f47365..9fbe5a97427 100644
--- a/packages/plugin-grainline/src/index.js
+++ b/packages/plugin-grainline/src/index.js
@@ -5,7 +5,7 @@ export default {
   name: name,
   version: version,
   hooks: {
-    preRender: svg => {
+    preRender: (svg) => {
       if (svg.attributes.get('freesewing:plugin-grainline') === false) {
         svg.attributes.set('freesewing:plugin-grainline', version)
         svg.defs += markers
diff --git a/packages/plugin-grainline/tests/grainline.test.js b/packages/plugin-grainline/tests/grainline.test.js
deleted file mode 100644
index 167564b3ffb..00000000000
--- a/packages/plugin-grainline/tests/grainline.test.js
+++ /dev/null
@@ -1,40 +0,0 @@
-import freesewing from '@freesewing/core'
-import { version } from "../package.json";
-
-
-const expect = require("chai").expect;
-const plugin = require("../dist/index.js");
-const round = freesewing.utils.round
-
-it("Should set the plugin name:version attribute", () => {
-  const pattern = new freesewing.Pattern().use(plugin);
-  pattern.draft().render();
-  expect(pattern.svg.attributes.get("freesewing:plugin-grainline")).to.equal(
-    version
-  );
-});
-
-it("Should run the default grainline macro", () => {
-  const pattern = new freesewing.Pattern().use(plugin);
-  pattern.parts.test = new pattern.Part();
-  pattern.parts.test.points.from = new pattern.Point(10, 20);
-  pattern.parts.test.points.to = new pattern.Point(10, 230);
-  const { macro } = pattern.parts.test.shorthand();
-  macro("grainline", {
-    from: pattern.parts.test.points.from,
-    to: pattern.parts.test.points.to
-  });
-
-  const c = pattern.parts.test.paths.grainline;
-  expect(c.attributes.get("class")).to.equal("note");
-  expect(c.attributes.get("marker-start")).to.equal("url(#grainlineFrom)");
-  expect(c.attributes.get("marker-end")).to.equal("url(#grainlineTo)");
-  expect(c.attributes.get("data-text")).to.equal("grainline");
-  expect(c.attributes.get("data-text-class")).to.equal("center fill-note");
-  expect(c.ops[0].type).to.equal("move");
-  expect(c.ops[1].type).to.equal("line");
-  expect(round(c.ops[0].to.x)).to.equal(10);
-  expect(round(c.ops[0].to.y)).to.equal(30.5);
-  expect(round(c.ops[1].to.x)).to.equal(10);
-  expect(round(c.ops[1].to.y)).to.equal(219.5);
-});
diff --git a/packages/plugin-grainline/tests/plugin.test.mjs b/packages/plugin-grainline/tests/plugin.test.mjs
new file mode 100644
index 00000000000..cd7364a6dc9
--- /dev/null
+++ b/packages/plugin-grainline/tests/plugin.test.mjs
@@ -0,0 +1,33 @@
+import chai from 'chai'
+import freesewing from '@freesewing/core'
+import plugin from '../dist/index.mjs'
+
+const expect = chai.expect
+const round = freesewing.utils.round
+
+describe('Grainline Plugin Tests', () => {
+  it('Should run the default grainline macro', () => {
+    const pattern = new freesewing.Pattern().use(plugin)
+    pattern.parts.test = new pattern.Part()
+    pattern.parts.test.points.from = new pattern.Point(10, 20)
+    pattern.parts.test.points.to = new pattern.Point(10, 230)
+    const { macro } = pattern.parts.test.shorthand()
+    macro('grainline', {
+      from: pattern.parts.test.points.from,
+      to: pattern.parts.test.points.to,
+    })
+
+    const c = pattern.parts.test.paths.grainline
+    expect(c.attributes.get('class')).to.equal('note')
+    expect(c.attributes.get('marker-start')).to.equal('url(#grainlineFrom)')
+    expect(c.attributes.get('marker-end')).to.equal('url(#grainlineTo)')
+    expect(c.attributes.get('data-text')).to.equal('grainline')
+    expect(c.attributes.get('data-text-class')).to.equal('center fill-note')
+    expect(c.ops[0].type).to.equal('move')
+    expect(c.ops[1].type).to.equal('line')
+    expect(round(c.ops[0].to.x)).to.equal(10)
+    expect(round(c.ops[0].to.y)).to.equal(30.5)
+    expect(round(c.ops[1].to.x)).to.equal(10)
+    expect(round(c.ops[1].to.y)).to.equal(219.5)
+  })
+})
diff --git a/packages/plugin-grainline/tests/shared.test.mjs b/packages/plugin-grainline/tests/shared.test.mjs
new file mode 100644
index 00000000000..42cd98f4655
--- /dev/null
+++ b/packages/plugin-grainline/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)