Start adding tests.

test/data.test.js

@@ -0,0 +1,23 @@
+/* global describe, it */
+
+const chai = require('chai');
+const proxyquire = require('proxyquire').noPreserveCache();
+const data = () => proxyquire('../lib/util/data.js', {});
+const path = require('path');
+
+describe('Data', () => {
+    describe('Get path', () => {
+        it('Should return correct path', () => {
+            const expected = path.normalize(path.join(__dirname, '..', 'data'));
+            const actual = data().getPath();
+            chai.assert.strictEqual(actual, expected);
+        });
+
+        it('Should return correct path when ZIGBEE2MQTT_DATA set', () => {
+            const expected = path.join('var', 'zigbee2mqtt');
+            process.env.ZIGBEE2MQTT_DATA = expected;
+            const actual = data().getPath();
+            chai.assert.strictEqual(actual, expected);
+        });
+    });
+});