Added unit tests, fixed lint error

Auditors: @petemill

Test Plan:
`npm run unittest -- --grep="window API unit tests"`

app/browser/windows.js

@@ -16,7 +16,6 @@ const messages = require('../../js/constants/messages')
 const settings = require('../../js/constants/settings')
 const windowState = require('../common/state/windowState')
 const pinnedSitesState = require('../common/state/pinnedSitesState')
-const pinnedSitesUtil = require('../common/lib/pinnedSitesUtil')
 
 // TODO(bridiver) - set window uuid
 let currentWindows = {}
@@ -338,6 +337,19 @@ const api = {
     }
 
     return windowState.WINDOW_ID_NONE
+  },
+
+  privateMethods: () => {
+    return process.env.NODE_ENV === 'test'
+    ? {
+      cleanupWindow,
+      getWindowState,
+      getWindowValue,
+      updateWindow,
+      siteMatchesTab,
+      updatePinnedTabs
+    }
+    : {}
   }
 }
 

test/unit/app/browser/windowsTest.js

@@ -0,0 +1,124 @@
+/* global describe, it, before, beforeEach, after, afterEach */
+const mockery = require('mockery')
+const sinon = require('sinon')
+const Immutable = require('immutable')
+const assert = require('assert')
+const fakeElectron = require('../../lib/fakeElectron')
+const fakeAdBlock = require('../../lib/fakeAdBlock')
+
+require('../../braveUnit')
+
+describe('window API unit tests', function () {
+  let windows, appActions
+  let appStore
+  let defaultState, createTabState, tabCloseState
+
+  before(function () {
+    mockery.enable({
+      warnOnReplace: false,
+      warnOnUnregistered: false,
+      useCleanCache: true
+    })
+
+    const tab1 = {
+      id: 1,
+      url: 'https://pinned-tab.com',
+      partitionNumber: 0,
+      windowId: 1,
+      pinned: true
+    }
+    const pinned1 = {
+      'https://pinned-tab.com|0|0': {
+        location: 'https://pinned-tab.com',
+        partitionNumber: 0,
+        title: 'Brave Software - Example Pinned Tab',
+        order: 1
+      }
+    }
+    const pinned2 = {
+      'https://another-pinned-tab.com|0|0': {
+        location: 'https://another-pinned-tab.com',
+        partitionNumber: pinned1.partitionNumber,
+        title: pinned1.title,
+        order: pinned1.order
+      }
+    }
+
+    defaultState = Immutable.fromJS({
+      pinnedSites: pinned1,
+      tabs: [tab1]
+    })
+
+    createTabState = Immutable.fromJS({
+      pinnedSites: pinned2,
+      tabs: [tab1]
+    })
+
+    tabCloseState = Immutable.fromJS({
+      pinnedSites: {},
+      tabs: [tab1]
+    })
+
+    appStore = {
+      getState: () => Immutable.fromJS(defaultState)
+    }
+
+    mockery.registerMock('electron', fakeElectron)
+    mockery.registerMock('ad-block', fakeAdBlock)
+    mockery.registerMock('../../js/stores/appStore', appStore)
+
+    windows = require('../../../../app/browser/windows')
+    appActions = require('../../../../js/actions/appActions')
+  })
+
+  after(function () {
+    mockery.disable()
+  })
+
+  describe('privateMethods', function () {
+    let updatePinnedTabs
+    let createTabRequestedSpy, tabCloseRequestedSpy
+    const win = {
+      id: 1,
+      webContents: {
+        browserWindowOptions: {
+          disposition: ''
+        }
+      }
+    }
+
+    before(function () {
+      const methods = windows.privateMethods()
+      updatePinnedTabs = methods.updatePinnedTabs
+    })
+    beforeEach(function () {
+      createTabRequestedSpy = sinon.spy(appActions, 'createTabRequested')
+      tabCloseRequestedSpy = sinon.spy(appActions, 'tabCloseRequested')
+    })
+    afterEach(function () {
+      createTabRequestedSpy.restore()
+      tabCloseRequestedSpy.restore()
+      appStore.getState = () => Immutable.fromJS(defaultState)
+    })
+
+    describe('updatePinnedTabs', function () {
+      it('takes no action if pinnedSites list matches tab state', function () {
+        updatePinnedTabs(win)
+        assert.equal(createTabRequestedSpy.calledOnce, false)
+        assert.equal(tabCloseRequestedSpy.calledOnce, false)
+      })
+
+      it('calls `appActions.createTabRequested` for pinnedSites not in tab state', function () {
+        appStore.getState = () => Immutable.fromJS(createTabState)
+        updatePinnedTabs(win)
+        assert.equal(createTabRequestedSpy.calledOnce, true)
+      })
+
+      it('calls `appActions.tabCloseRequested` for items in tab state but not in pinnedSites', function () {
+        appStore.getState = () => Immutable.fromJS(tabCloseState)
+        updatePinnedTabs(win)
+        assert.equal(tabCloseRequestedSpy.calledOnce, true)
+      })
+    })
+  })
+})