diff --git a/package.json b/package.json
index c2b9644..e22c2ef 100644
--- a/package.json
+++ b/package.json
@@ -4,7 +4,7 @@
   "description": "Simple helper for turning on/off connected/disconnected monitors with xrandr",
   "main": "indes.js",
   "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "test": "mocha"
   },
   "bin": {
     "swm": "./cli.js"
@@ -27,5 +27,10 @@
     "minimist": "^1.2.0",
     "xdg": "^0.1.1",
     "xrandr-parse": "^0.1.1"
+  },
+  "devDependencies": {
+    "mocha": "^2.4.5",
+    "proxyquire": "^1.7.4",
+    "sinon": "^1.17.3"
   }
 }
diff --git a/test/swm.tests.js b/test/swm.tests.js
new file mode 100644
index 0000000..5c82ac4
--- /dev/null
+++ b/test/swm.tests.js
@@ -0,0 +1,76 @@
+'use strict';
+
+const sinon = require('sinon');
+const assert = require('assert');
+const proxyquire = require('proxyquire');
+
+describe('swm', () => {
+    let sandbox;
+
+    beforeEach(() => {
+        sandbox = sinon.sandbox.create();
+    });
+
+    afterEach(function() {
+        sandbox.restore();
+    });
+
+    describe('getDevices', () => {
+        let execStub;
+        let xrandrParseStub;
+        let swm;
+
+        beforeEach(() => {
+            execStub = sandbox.stub();
+            xrandrParseStub = sandbox.stub();
+            swm = proxyquire('../swm.js', {
+                child_process: {
+                    exec: execStub
+                },
+                'xrandr-parse': xrandrParseStub
+            });
+        });
+
+        it('calls exec', () => {
+            swm.getDevices();
+
+            assert.equal(execStub.callCount, 1);
+            assert.equal(execStub.args[0][0], 'xrandr');
+        });
+
+        it('returns promise', () => {
+            const devices = swm.getDevices();
+            assert.equal(typeof devices.then, 'function');
+            assert.equal(typeof devices.catch, 'function');
+        });
+
+        it('rejects when exec passes error', (done) => {
+            const devices = swm.getDevices();
+            const cb = execStub.args[0][1];
+            cb('some error');
+
+            return devices.catch((err) => {
+                assert.equal(xrandrParseStub.callCount, 0);
+                assert.equal(err, 'some error');
+                done();
+            });
+
+        });
+
+        it('parses result', (done) => {
+            xrandrParseStub.returns('some result');
+            const devices = swm.getDevices();
+            const cb = execStub.args[0][1];
+            cb(null, 'stdout');
+
+            return devices.then((result) => {
+                assert.equal(xrandrParseStub.args[0][0], 'stdout');
+                assert.equal(xrandrParseStub.callCount, 1);
+                assert.equal(result, 'some result');
+                done();
+            });
+
+        });
+    });
+});
+