diff --git a/circle.yml b/circle.yml
new file mode 100644
index 0000000..100709f
--- /dev/null
+++ b/circle.yml
@@ -0,0 +1,9 @@
+test:
+  override:
+    - nvm install 0.12 && npm test
+    - nvm install 4 && npm test
+  post:
+    - npm install
+    - istanbul cover ./node_modules/mocha/bin/_mocha --report lcovonly -- -R spec
+    - cat ./coverage/lcov.info | ./node_modules/.bin/codacy-coverage
+    - rm -rf ./coverage
diff --git a/package.json b/package.json
index 256a2a4..1971ef2 100644
--- a/package.json
+++ b/package.json
@@ -36,17 +36,21 @@
   },
   "preferGlobal": "true",
   "scripts": {
-    "release": "bash release.sh"
+    "release": "bash release.sh",
+    "test": "mocha",
+    "codacy": "istanbul cover ./node_modules/mocha/bin/_mocha --report lcovonly -- -R spec && cat ./coverage/lcov.info | ./node_modules/.bin/codacy-coverage && rm -rf ./coverage"
   },
   "main": "./src/diff2html.js",
   "dependencies": {
     "diff": "2.2.*"
   },
   "devDependencies": {
-    "webpack": "1.12.*",
-    "uglifyjs": "2.4.*",
+    "codacy-coverage": "^1.1.3",
+    "istanbul": "^0.4.1",
     "less": "2.5.*",
-    "nodeunit": "^0.9.1"
+    "mocha": "^2.3.4",
+    "uglifyjs": "2.4.*",
+    "webpack": "1.12.*"
   },
   "license": "MIT",
   "files": [
diff --git a/test/line-by-line-tests.js b/test/line-by-line-tests.js
new file mode 100644
index 0000000..9331fd8
--- /dev/null
+++ b/test/line-by-line-tests.js
@@ -0,0 +1,22 @@
+var assert = require('assert');
+
+var LineByLinePrinter = require('../src/line-by-line-printer.js').LineByLinePrinter;
+
+describe('LineByLinePrinter', function() {
+  describe('_generateEmptyDiff', function() {
+    it('should return an empty diff', function() {
+
+      var lineByLinePrinter = new LineByLinePrinter({});
+      var fileHtml = lineByLinePrinter._generateEmptyDiff();
+      var expected = '<tr>\n' +
+        '  <td class="d2h-info">' +
+        '    <div class="d2h-code-line d2h-info">' +
+        'File without changes' +
+        '    </div>' +
+        '  </td>\n' +
+        '</tr>\n';
+
+      assert.equal(expected, fileHtml);
+    });
+  });
+});
diff --git a/test/side-by-side-printer-tests.js b/test/side-by-side-printer-tests.js
new file mode 100644
index 0000000..b11d4ae
--- /dev/null
+++ b/test/side-by-side-printer-tests.js
@@ -0,0 +1,24 @@
+var assert = require('assert');
+
+var SideBySidePrinter = require('../src/side-by-side-printer.js').SideBySidePrinter;
+
+describe('SideBySidePrinter', function() {
+  describe('generateEmptyDiff', function() {
+    it('should return an empty diff', function() {
+
+      var sideBySidePrinter = new SideBySidePrinter({});
+      var fileHtml = sideBySidePrinter.generateEmptyDiff();
+      var expectedRight = '';
+      var expectedLeft = '<tr>\n' +
+        '  <td class="d2h-info">' +
+        '    <div class="d2h-code-side-line d2h-info">' +
+        'File without changes' +
+        '    </div>' +
+        '  </td>\n' +
+        '</tr>\n';
+
+      assert.equal(expectedRight, fileHtml.right);
+      assert.equal(expectedLeft, fileHtml.left);
+    });
+  });
+});
diff --git a/tests/line-by-line-tests.js b/tests/line-by-line-tests.js
deleted file mode 100644
index cfc64ea..0000000
--- a/tests/line-by-line-tests.js
+++ /dev/null
@@ -1,18 +0,0 @@
-var LineByLinePrinter = require('../src/line-by-line-printer.js').LineByLinePrinter;
-
-module.exports = {
-  testGenerateEmptyDiff: function (test) {
-    var lineByLinePrinter = new LineByLinePrinter({});
-    var fileHtml = lineByLinePrinter._generateEmptyDiff();
-    var expected = '<tr>\n' +
-      '  <td class="d2h-info">' +
-      '    <div class="d2h-code-line d2h-info">' +
-      'File without changes' +
-      '    </div>' +
-      '  </td>\n' +
-      '</tr>\n';
-
-    test.equal(expected, fileHtml);
-    test.done();
-  }
-};
diff --git a/tests/side-by-side-printer-tests.js b/tests/side-by-side-printer-tests.js
deleted file mode 100644
index 506f8e4..0000000
--- a/tests/side-by-side-printer-tests.js
+++ /dev/null
@@ -1,19 +0,0 @@
-var SideBySidePrinter = require('../src/side-by-side-printer.js').SideBySidePrinter;
-
-module.exports = {
-  testGenerateEmptyDiff: function (test) {
-    var sideBySidePrinter = new SideBySidePrinter({});
-    var fileHtml = sideBySidePrinter.generateEmptyDiff();
-    var expectedRight = '';
-    var expectedLeft = '<tr>\n' +
-      '  <td class="d2h-info">' +
-      '    <div class="d2h-code-side-line d2h-info">' +
-      'File without changes' +
-      '    </div>' +
-      '  </td>\n' +
-      '</tr>\n';
-    test.equal(expectedRight, fileHtml.right);
-    test.equal(expectedLeft, fileHtml.left);
-    test.done();
-  }
-};