test: increase test coverage

src/app/settings/settings.component.ts

@@ -1,11 +1,11 @@
 import { TranslateService } from '@ngx-translate/core';
-import { Component, OnInit, OnDestroy } from '@angular/core';
+import { Component, OnInit } from '@angular/core';
 import { FormGroup, FormBuilder } from '@angular/forms';
 import { StorageMap } from '@ngx-pwa/local-storage';
 import { Router } from '@angular/router';
 import { MatSnackBar } from '@angular/material/snack-bar';
 import { Observable, Subscription } from 'rxjs';
-import { Settings, VideoPlayer } from './settings.interface';
+import { Settings, SETTINGS_STORE_KEY, VideoPlayer } from './settings.interface';
 import { HttpClient } from '@angular/common/http';
 import * as semver from 'semver';
 import { ElectronService } from '../services/electron.service';
@@ -14,6 +14,7 @@ import { EPG_FETCH } from '../../../shared/ipc-commands';
 import { Language } from './language.enum';
 import { Theme } from './theme.enum';
 import { SettingsService } from './../services/settings.service';
+import { catchError } from 'rxjs/operators';
 
 /** Url of the package.json file in the app repository, required to get the version of the released app */
 const PACKAGE_JSON_URL =
@@ -24,10 +25,7 @@ const PACKAGE_JSON_URL =
     templateUrl: './settings.component.html',
     styleUrls: ['./settings.component.scss'],
 })
-export class SettingsComponent implements OnInit, OnDestroy {
-    /** Subscription object */
-    private subscription: Subscription = new Subscription();
-
+export class SettingsComponent implements OnInit {
     /** List with available languages as enum */
     languageEnum = Language;
 
@@ -61,7 +59,8 @@ export class SettingsComponent implements OnInit, OnDestroy {
     themeEnum = Theme;
 
     /**
-     * Creates an instance of SettingsComponent and injects some dependencies into the component
+     * Creates an instance of SettingsComponent and injects 
+     * required dependencies into the component
      * @param channelQuery
      * @param electronService
      * @param formBuilder
@@ -91,84 +90,112 @@ export class SettingsComponent implements OnInit, OnDestroy {
             theme: Theme.LightTheme,
         });
 
-        this.subscription.add(
-            this.http
-                .get(PACKAGE_JSON_URL)
-                .subscribe((response: { version: string }) => {
-                    this.version = this.electronService.getAppVersion();
-                    const isOutdated = semver.lt(
-                        this.version,
-                        response.version
-                    );
-
-                    if (isOutdated) {
-                        this.updateMessage = `${
-                            this.translate.instant(
-                                'SETTINGS.NEW_VERSION_AVAILABLE'
-                            ) as string
-                        }: ${response.version}`;
-                    } else {
-                        this.updateMessage = this.translate.instant(
-                            'SETTINGS.LATEST_VERSION'
-                        );
-                    }
-                })
-        );
+        this.checkAppVersion();
     }
 
     /**
-     * Reads the config object from the browsers storage (indexed db)
+     * Reads the config object from the browsers 
+     * storage (indexed db)
      */
     ngOnInit(): void {
-        this.subscription.add(
-            this.storage.get('settings').subscribe((settings: Settings) => {
-                if (settings) {
-                    this.settingsForm.setValue({
-                        player: settings.player
-                            ? settings.player
-                            : VideoPlayer.VideoJs,
-                        epgUrl: settings.epgUrl ? settings.epgUrl : '',
-                        language: settings.language
-                            ? settings.language
-                            : Language.ENGLISH,
-                        showCaptions: settings.showCaptions
-                            ? settings.showCaptions
-                            : false,
-                        theme: settings.theme
-                            ? settings.theme
-                            : Theme.LightTheme,
-                    });
-                }
-            })
+        this.storage.get(SETTINGS_STORE_KEY).subscribe((settings: Settings) => {
+            if (settings) {
+                this.settingsForm.setValue({
+                    player: settings.player
+                        ? settings.player
+                        : VideoPlayer.VideoJs,
+                    epgUrl: settings.epgUrl ? settings.epgUrl : '',
+                    language: settings.language
+                        ? settings.language
+                        : Language.ENGLISH,
+                    showCaptions: settings.showCaptions
+                        ? settings.showCaptions
+                        : false,
+                    theme: settings.theme
+                        ? settings.theme
+                        : Theme.LightTheme,
+                });
+            }
+        });
+    }
+
+    /**
+     * Checks whether the latest version of the application 
+     * is used and updates the version message in the
+     * settings UI
+     */
+    checkAppVersion(): void {
+        this.http
+        .get(PACKAGE_JSON_URL)
+        .pipe(catchError(err => {
+            console.error(err);
+            throw new Error(err);
+        }))
+        .subscribe((response: { version: string }) => {
+            this.showVersionInformation(response.version);
+        });
+    }
+
+    /**
+     * Updates the message in settings UI about the used 
+     * version of the app
+     * @param currentVersion current version of the application
+     */
+    showVersionInformation(currentVersion: string): void {
+        const isOutdated = this.isCurrentVersionOutdated(currentVersion);
+
+        if (isOutdated) {
+            this.updateMessage = `${
+                this.translate.instant(
+                    'SETTINGS.NEW_VERSION_AVAILABLE'
+                ) as string
+            }: ${currentVersion}`;
+        } else {
+            this.updateMessage = this.translate.instant(
+                'SETTINGS.LATEST_VERSION'
+            );
+        }
+    }
+
+    /**
+     * Compares actual with latest version of the 
+     * application  
+     * @param latestVersion latest version
+     * @returns returns true if an update is available
+     */
+    isCurrentVersionOutdated(latestVersion: string): boolean {
+        this.version = this.electronService.getAppVersion();
+        return semver.lt(
+            this.version,
+            latestVersion
         );
     }
 
     /**
-     * Triggers on form submit and saves the config object to the indexed db store
+     * Triggers on form submit and saves the config object to
+     * the indexed db store
      */
     onSubmit(): void {
-        this.subscription.add(
-            this.storage
-                .set('settings', this.settingsForm.value)
-                .subscribe(() => {
-                    this.settingsForm.markAsPristine();
-                    // check whether the epg url was changed or not
-                    if (this.settingsForm.value.epgUrl) {
-                        this.fetchEpg();
+        this.storage
+            .set(SETTINGS_STORE_KEY, this.settingsForm.value)
+            .subscribe(() => {
+                this.settingsForm.markAsPristine();
+                // check whether the epg url was changed or not
+                if (this.settingsForm.value.epgUrl) {
+                    this.fetchEpg();
+                }
+                this.translate.use(this.settingsForm.value.language);
+                this.settingsService.changeTheme(
+                    this.settingsForm.value.theme
+                );
+                this.snackBar.open(
+                    this.translate.instant('SETTINGS.SETTINGS_SAVED'),
+                    null,
+                    {
+                        duration: 2000,
                     }
-                    this.translate.use(this.settingsForm.value.language);
-                    this.settingsService.changeTheme(
-                        this.settingsForm.value.theme
-                    );
-                    this.snackBar.open(
-                        this.translate.instant('SETTINGS.SETTINGS_SAVED'),
-                        null,
-                        {
-                            duration: 2000,
-                        }
-                    );
-                })
-        );
+                );
+            });
     }
 
     /**
@@ -178,18 +205,11 @@ export class SettingsComponent implements OnInit, OnDestroy {
         this.router.navigateByUrl('/', { skipLocationChange: true });
     }
 
-    /**
-     * Unsubscribe on destroy
-     */
-    ngOnDestroy(): void {
-        this.subscription.unsubscribe();
-    }
-
     /**
      * Fetches and updates EPG from the given URL
      */
     fetchEpg(): void {
-        this.electronService.ipcRenderer.send(EPG_FETCH, {
+        this.electronService.sendIpcEvent(EPG_FETCH, {
             url: this.settingsForm.value.epgUrl,
         });
         this.snackBar.open(this.translate.instant('EPG.FETCH_EPG'), 'Close', {