diff --git a/.github/workflows/node.js.yml b/.github/workflows/node.js.yml
index c0cf5e0..f2d3cfc 100644
--- a/.github/workflows/node.js.yml
+++ b/.github/workflows/node.js.yml
@@ -6,22 +6,38 @@ name: Node.js CI
 on: ["push", "pull_request"]
 
 jobs:
-  build:
+  test:
 
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-18.04
 
     strategy:
       matrix:
-        node-version: [16.x]
+        node-version: [12.x, 13.x, 14.x, 15.x, 16.x]
 
     steps:
     - uses: actions/checkout@v2
-#    - run: sudo apt install gfortran
-#    - run: cd reference && make && cd ..
+    - run: sudo apt install gfortran
+    - run: cd reference && make && cd ..
     - name: Use Node.js ${{ matrix.node-version }}
       uses: actions/setup-node@v1
       with:
         node-version: ${{ matrix.node-version }}
     - run: npm ci
-    - run: npm run build --if-present
+    - run: npm run build
     - run: npm test
+    - name: Coveralls
+      uses: coverallsapp/github-action@master
+      with:
+        github-token: ${{ secrets.GITHUB_TOKEN }}
+        flag-name: run-${{ matrix.test_number }}
+        parallel: true
+
+  finish:
+    needs: test
+    runs-on: ubuntu-18.04
+    steps:
+    - name: Coveralls Finished
+      uses: coverallsapp/github-action@master
+      with:
+        github-token: ${{ secrets.github_token }}
+        parallel-finished: true
diff --git a/.github/workflows/npm-publish.yml b/.github/workflows/npm-publish.yml
index b2cb83b..7b7d37e 100644
--- a/.github/workflows/npm-publish.yml
+++ b/.github/workflows/npm-publish.yml
@@ -9,7 +9,7 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-18.04
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-node@v1
@@ -23,7 +23,7 @@ jobs:
 
   publish-npm:
     needs: build
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-18.04
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-node@v1
diff --git a/.github/workflows/website.yml b/.github/workflows/website.yml
index a8bf998..f659544 100644
--- a/.github/workflows/website.yml
+++ b/.github/workflows/website.yml
@@ -7,7 +7,7 @@ on:
 
 jobs:
   publish:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-18.04
     steps:
       -
         name: Checkout
diff --git a/.gitignore b/.gitignore
index ee20b49..e66cc63 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@
 /public
 /.cache
 /.parcel-cache
+/coverage
diff --git a/README.md b/README.md
index 30be9ab..1d48ee5 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # egm96-universal
 
-[![Node.js CI](https://github.com/nicolas-van/egm96-universal/workflows/Node.js%20CI/badge.svg)](https://github.com/nicolas-van/egm96-universal/actions?query=workflow%3A%22Node.js+CI%22) [![npm](https://img.shields.io/npm/v/egm96-universal)](https://www.npmjs.com/package/egm96-universal)
+[![Node.js CI](https://github.com/nicolas-van/egm96-universal/workflows/Node.js%20CI/badge.svg)](https://github.com/nicolas-van/egm96-universal/actions?query=workflow%3A%22Node.js+CI%22) [![npm](https://img.shields.io/npm/v/egm96-universal)](https://www.npmjs.com/package/egm96-universal) [![Coverage Status](https://coveralls.io/repos/github/nicolas-van/egm96-universal/badge.svg?branch=master)](https://coveralls.io/github/nicolas-van/egm96-universal?branch=master)
 
 A library to convert between EGM96-relative altitudes and WGS84 ellipsoid-relative altitudes.
 
diff --git a/package.json b/package.json
index 983008d..292237e 100644
--- a/package.json
+++ b/package.json
@@ -18,7 +18,7 @@
     "convert-data": "node ./convertDataFile.js",
     "test": "npm run prebuild && npm run lint && npm run jest",
     "lint": "npm run prebuild && eslint \"*.js\" \"src/**/*.js\"",
-    "jest": "npm run prebuild && jest",
+    "jest": "npm run prebuild && jest --config=./jest.config.js --coverage",
     "build": "npm run rollup",
     "rollup": "rollup -c",
     "website-build": "npm run prebuild && parcel build demo/index.html --dist-dir public --public-url ./",
diff --git a/src/egm96.reference.test.js b/src/egm96.reference.test.js
index 8cd5204..83330c3 100644
--- a/src/egm96.reference.test.js
+++ b/src/egm96.reference.test.js
@@ -1,4 +1,3 @@
-/* eslint-disable */
 
 import * as egm96 from './egm96'
 import * as cp from 'child_process'
@@ -94,7 +93,6 @@ test('empty test', () => {
   expect(true).toBe(true)
 })
 
-/*
 test('intersection test', () => {
   const coords = []
   for (let a = -85; a <= 85; a += 20) {
@@ -114,7 +112,6 @@ test('non intersection test', () => {
     testComparison(lat, lon, false)
   }
 })
-*/
 
 // 100 randomly generated coordinates
 const samples = [