Handle missing serial numbers

.travis.yml

@@ -14,3 +14,5 @@ before_install:
 
 script:
   - npm run lint
+# TODO: Tests don't work in CI yet
+# - npm run test

lib/AccessoryManager.js

@@ -99,15 +99,10 @@ class AccessoryManager {
     this._zwave.onNodeReady(zwaveNodeId, zwaveNode => {
       this._accessoryReadyState = READY_STATE_READY
 
-      const { value: serialNumber } = this._zwave.findNodeValue(zwaveNodeId, {
-        class_id: COMMAND_CLASS_MANUFACTURER_SPECIFIC,
-        index: MANUFACTURER_SPECIFIC_INDEX_SERIAL_NUMBER
-      })
-
       this._configureAccessoryInformationService(
         zwaveNode.manufacturer,
         zwaveNode.product,
-        serialNumber
+        this._findNodeSerialNumber(zwaveNodeId)
       )
     })
   }
@@ -631,6 +626,21 @@ class AccessoryManager {
       this._log(`${accessoryDisplayName} "${characteristicName}" characteristic value updated to ${value} outside of HomeKit`)
     })
   }
+
+  /**
+   * Get serial number from node
+   *
+   * @param {Number} zwaveNodeId
+   * @returns {?String} The serial number, or null if the node doesn't have one
+   */
+  _findNodeSerialNumber (zwaveNodeId) {
+    const { value: serialNumber = null } = this._zwave.findNodeValue(zwaveNodeId, {
+      class_id: COMMAND_CLASS_MANUFACTURER_SPECIFIC,
+      index: MANUFACTURER_SPECIFIC_INDEX_SERIAL_NUMBER
+    }) || {}
+
+    return serialNumber
+  }
 }
 
 module.exports = AccessoryManager

lib/AccessoryManager.test.js

@@ -0,0 +1,30 @@
+const AccessoryManager = require('./AccessoryManager')
+
+describe('_findNodeSerialNumber', () => {
+  const mockZwave = {}
+  const manager = new AccessoryManager({}, {}, console.log, mockZwave)
+
+  function mockFindNodeResult (result) {
+    mockZwave.findNodeValue = (_nodeId, _options = {}) => result
+  }
+
+  test('returns serialNumber if provided by ZWave', () => {
+    mockFindNodeResult({ value: '12345' })
+    expect(manager._findNodeSerialNumber(1)).toBe('12345')
+  })
+
+  test('returns null if ZWave value is undefined', () => {
+    mockFindNodeResult({ value: undefined })
+    expect(manager._findNodeSerialNumber(1)).toBe(null)
+  })
+
+  test('returns null if ZWave result is empty', () => {
+    mockFindNodeResult({})
+    expect(manager._findNodeSerialNumber(1)).toBe(null)
+  })
+
+  test('returns null if entire ZWave result is undefined', () => {
+    mockFindNodeResult(undefined)
+    expect(manager._findNodeSerialNumber(1)).toBe(null)
+  })
+})