diff --git a/src/main/notifications/index.test.js b/src/main/notifications/index.test.js
new file mode 100644
index 00000000..3635dd06
--- /dev/null
+++ b/src/main/notifications/index.test.js
@@ -0,0 +1,170 @@
+// Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+'use strict';
+
+import {Notification, shell} from 'electron';
+
+import {PLAY_SOUND} from 'common/communication';
+import {TAB_MESSAGING} from 'common/tabs/TabView';
+
+import * as WindowManager from '../windows/windowManager';
+
+import {displayMention, displayDownloadCompleted, currentNotifications} from './index';
+
+const mentions = [];
+
+jest.mock('electron', () => {
+    class NotificationMock {
+        static isSupported = jest.fn();
+        static didConstruct = jest.fn();
+
+        constructor(options) {
+            NotificationMock.didConstruct();
+            this.callbackMap = new Map();
+            mentions.push({body: options.body, value: this});
+        }
+
+        on = (event, callback) => {
+            this.callbackMap.set(event, callback);
+        }
+
+        show = jest.fn().mockImplementation(() => {
+            this.callbackMap.get('show')();
+        });
+
+        click = jest.fn().mockImplementation(() => {
+            this.callbackMap.get('click')();
+        });
+
+        close = jest.fn();
+    }
+
+    return {
+        app: {
+            getAppPath: () => '/path/to/app',
+        },
+        Notification: NotificationMock,
+        shell: {
+            showItemInFolder: jest.fn(),
+        },
+    };
+});
+
+jest.mock('electron-log', () => ({
+    info: jest.fn(),
+    error: jest.fn(),
+}));
+
+jest.mock('../windows/windowManager', () => ({
+    getServerNameByWebContentsId: () => 'server_name',
+    sendToRenderer: jest.fn(),
+    flashFrame: jest.fn(),
+    switchTab: jest.fn(),
+}));
+
+describe('main/notifications', () => {
+    describe('displayMention', () => {
+        beforeEach(() => {
+            Notification.isSupported.mockImplementation(() => true);
+        });
+
+        it('should do nothing when Notification is not supported', () => {
+            Notification.isSupported.mockImplementation(() => false);
+            displayMention(
+                'test',
+                'test body',
+                {id: 'channel_id'},
+                'team_id',
+                'http://server-1.com/team_id/channel_id',
+                false,
+                {id: 1},
+                {},
+            );
+            expect(Notification.didConstruct).not.toBeCalled();
+        });
+
+        it('should play notification sound when custom sound is provided', () => {
+            displayMention(
+                'test',
+                'test body',
+                {id: 'channel_id'},
+                'team_id',
+                'http://server-1.com/team_id/channel_id',
+                false,
+                {id: 1},
+                {soundName: 'test_sound'},
+            );
+            expect(WindowManager.sendToRenderer).toHaveBeenCalledWith(PLAY_SOUND, 'test_sound');
+        });
+
+        it('should remove existing notification from the same channel/team on windows', () => {
+            const originalPlatform = process.platform;
+            Object.defineProperty(process, 'platform', {
+                value: 'win32',
+            });
+
+            displayMention(
+                'test',
+                'test body',
+                {id: 'channel_id'},
+                'team_id',
+                'http://server-1.com/team_id/channel_id',
+                false,
+                {id: 1},
+                {},
+            );
+
+            expect(currentNotifications.has('team_id:channel_id')).toBe(true);
+
+            const existingMention = currentNotifications.get('team_id:channel_id');
+            currentNotifications.delete = jest.fn();
+            displayMention(
+                'test',
+                'test body 2',
+                {id: 'channel_id'},
+                'team_id',
+                'http://server-1.com/team_id/channel_id',
+                false,
+                {id: 1},
+                {},
+            );
+
+            expect(currentNotifications.delete).toHaveBeenCalled();
+            expect(existingMention.close).toHaveBeenCalled();
+
+            Object.defineProperty(process, 'platform', {
+                value: originalPlatform,
+            });
+        });
+
+        it('should switch tab when clicking on notification', () => {
+            displayMention(
+                'click_test',
+                'mention_click_body',
+                {id: 'channel_id'},
+                'team_id',
+                'http://server-1.com/team_id/channel_id',
+                false,
+                {id: 1, send: jest.fn()},
+                {},
+            );
+            const mention = mentions.find((m) => m.body === 'mention_click_body');
+            mention.value.click();
+            expect(WindowManager.switchTab).toHaveBeenCalledWith('server_name', TAB_MESSAGING);
+        });
+    });
+
+    describe('displayDownloadCompleted', () => {
+        it('should open file when clicked', () => {
+            displayDownloadCompleted(
+                'test_filename',
+                '/path/to/file',
+                'server_name',
+            );
+            const mention = mentions.find((m) => m.body.includes('test_filename'));
+            mention.value.click();
+            expect(shell.showItemInFolder).toHaveBeenCalledWith('/path/to/file');
+        });
+    });
+});
diff --git a/src/main/notifications/index.ts b/src/main/notifications/index.ts
index 5a493a2e..4bea76fa 100644
--- a/src/main/notifications/index.ts
+++ b/src/main/notifications/index.ts
@@ -14,7 +14,7 @@ import * as windowManager from '../windows/windowManager';
 import {Mention} from './Mention';
 import {DownloadNotification} from './Download';
 
-const currentNotifications = new Map();
+export const currentNotifications = new Map();
 
 export function displayMention(title: string, body: string, channel: {id: string}, teamId: string, url: string, silent: boolean, webcontents: Electron.WebContents, data: MentionData) {
     if (!Notification.isSupported()) {