test(unit): add some basic tests for Lightning class

app/lib/lnd/lightning.js

@@ -89,7 +89,9 @@ class Lightning {
    */
   disconnect() {
     this.unsubscribe()
-    this.lnd.close()
+    if (this.lnd) {
+      this.lnd.close()
+    }
   }
 
   /**

test/unit/lnd/lightning.spec.js

@@ -0,0 +1,53 @@
+import { BrowserWindow } from 'electron'
+import Lightning from 'lib/lnd/lightning'
+
+jest.mock('electron-store')
+jest.mock('lib/lnd/subscribe/transactions')
+jest.mock('lib/lnd/subscribe/invoices')
+jest.mock('lib/lnd/subscribe/channelgraph')
+
+describe('Lightning', function() {
+  describe('Constructor', () => {
+    beforeAll(() => (this.lightning = new Lightning()))
+
+    describe('initial values', () => {
+      it('should set the "mainWindow" property to null', () => {
+        expect(this.lightning.mainWindow).toBeNull()
+      })
+      it('should set the "lnd" property to null', () => {
+        expect(this.lightning.lnd).toBeNull()
+      })
+      it('should initialise the "subscriptions" object with null values', () => {
+        expect(this.lightning.subscriptions).toMatchObject({
+          channelGraph: null,
+          invoices: null,
+          transactions: null
+        })
+      })
+    })
+  })
+
+  describe('subscribe()', () => {
+    beforeAll(() => {
+      this.window = new BrowserWindow({})
+      this.lightning = new Lightning()
+      this.lightning.subscribe(this.window)
+    })
+
+    it('should assign the window to the "mainWindow" property', () => {
+      expect(this.lightning.mainWindow).toBe(this.window)
+    })
+  })
+
+  describe('unsubscribe()', () => {
+    beforeAll(() => {
+      this.lightning = new Lightning()
+      this.lightning.mainWindow = new BrowserWindow({})
+      this.lightning.unsubscribe()
+    })
+
+    it('should unassign the "mainWindow" property', () => {
+      expect(this.lightning.mainWindow).toBeNull()
+    })
+  })
+})