diff --git a/packages/cli/package-lock.json b/packages/cli/package-lock.json
index ebd71718..931eed02 100644
--- a/packages/cli/package-lock.json
+++ b/packages/cli/package-lock.json
@@ -42,12 +42,6 @@
         "rxjs": "^6.4.0"
       }
     },
-    "@types/jasmine": {
-      "version": "3.5.11",
-      "resolved": "https://registry.npmjs.org/@types/jasmine/-/jasmine-3.5.11.tgz",
-      "integrity": "sha512-fg1rOd/DehQTIJTifGqGVY6q92lDgnLfs7C6t1ccSwQrMyoTGSoH6wWzhJDZb6ezhsdwAX4EIBLe8w5fXWmEng==",
-      "dev": true
-    },
     "@types/mime-types": {
       "version": "2.1.0",
       "resolved": "https://registry.npmjs.org/@types/mime-types/-/mime-types-2.1.0.tgz",
@@ -58,15 +52,6 @@
       "resolved": "https://registry.npmjs.org/@types/minimist/-/minimist-1.2.0.tgz",
       "integrity": "sha1-aaI6OtKcrwCX8G7aWbNh7i8GOfY="
     },
-    "@types/mock-fs": {
-      "version": "4.10.0",
-      "resolved": "https://registry.npmjs.org/@types/mock-fs/-/mock-fs-4.10.0.tgz",
-      "integrity": "sha512-FQ5alSzmHMmliqcL36JqIA4Yyn9jyJKvRSGV3mvPh108VFatX7naJDzSG4fnFQNZFq9dIx0Dzoe6ddflMB2Xkg==",
-      "dev": true,
-      "requires": {
-        "@types/node": "*"
-      }
-    },
     "@types/node": {
       "version": "12.12.30",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-12.12.30.tgz",
diff --git a/packages/cli/src/index.ts b/packages/cli/src/index.ts
index 1d0e6a11..87b3f56c 100644
--- a/packages/cli/src/index.ts
+++ b/packages/cli/src/index.ts
@@ -15,11 +15,11 @@
  */
 
 import {Cli} from './lib/Cli';
-import {Log} from '@bubblewrap/core';
+import {ConsoleLog} from '@bubblewrap/core';
 
 module.exports = async (): Promise<void> => {
   const cli = new Cli();
-  const log = new Log('cli');
+  const log = new ConsoleLog('cli');
   const args = process.argv.slice(2);
 
   let success;
diff --git a/packages/cli/src/lib/cmds/build.ts b/packages/cli/src/lib/cmds/build.ts
index 660aaa7f..ea755280 100644
--- a/packages/cli/src/lib/cmds/build.ts
+++ b/packages/cli/src/lib/cmds/build.ts
@@ -15,7 +15,7 @@
  */
 
 import {AndroidSdkTools, Config, DigitalAssetLinks, GradleWrapper, JdkHelper, KeyTool, Log,
-  TwaManifest, JarSigner, SigningKeyInfo, Result} from '@bubblewrap/core';
+  ConsoleLog, TwaManifest, JarSigner, SigningKeyInfo, Result} from '@bubblewrap/core';
 import * as path from 'path';
 import * as fs from 'fs';
 import {enUS as messages} from '../strings';
@@ -38,7 +38,7 @@ class Build {
   private jarSigner: JarSigner;
 
   constructor(private config: Config, private args: ParsedArgs,
-      private log = new Log('build'), private prompt: Prompt = new InquirerPrompt()) {
+      private log: Log = new ConsoleLog('build'), private prompt: Prompt = new InquirerPrompt()) {
     this.jdkHelper = new JdkHelper(process, this.config);
     this.androidSdkTools = new AndroidSdkTools(process, this.config, this.jdkHelper, this.log);
     this.keyTool = new KeyTool(this.jdkHelper, this.log);
@@ -191,7 +191,7 @@ class Build {
 }
 
 export async function build(config: Config, args: ParsedArgs,
-    log = new Log('build'), prompt: Prompt = new InquirerPrompt()): Promise<boolean> {
+    log: Log = new ConsoleLog('build'), prompt: Prompt = new InquirerPrompt()): Promise<boolean> {
   const build = new Build(config, args, log, prompt);
   return build.build();
 }
diff --git a/packages/cli/src/lib/cmds/help.ts b/packages/cli/src/lib/cmds/help.ts
index 09d4e952..c032b99e 100644
--- a/packages/cli/src/lib/cmds/help.ts
+++ b/packages/cli/src/lib/cmds/help.ts
@@ -14,7 +14,7 @@
  *  limitations under the License.
  */
 
-import {Log} from '@bubblewrap/core';
+import {Log, ConsoleLog} from '@bubblewrap/core';
 import {ParsedArgs} from 'minimist';
 
 const HELP_MESSAGES = new Map<string, string>(
@@ -87,7 +87,7 @@ const HELP_MESSAGES = new Map<string, string>(
     ],
 );
 
-export async function help(args: ParsedArgs, log = new Log('help')): Promise<boolean> {
+export async function help(args: ParsedArgs, log: Log = new ConsoleLog('help')): Promise<boolean> {
   // minimist uses an `_` object to store details.
   const command = args._[1];
   const message = HELP_MESSAGES.get(command) || HELP_MESSAGES.get('main');
diff --git a/packages/cli/src/lib/cmds/install.ts b/packages/cli/src/lib/cmds/install.ts
index c4582c89..eef4a4ef 100644
--- a/packages/cli/src/lib/cmds/install.ts
+++ b/packages/cli/src/lib/cmds/install.ts
@@ -14,7 +14,7 @@
  *  limitations under the License.
  */
 
-import {AndroidSdkTools, Config, JdkHelper, Log} from '@bubblewrap/core';
+import {AndroidSdkTools, Config, JdkHelper, Log, ConsoleLog} from '@bubblewrap/core';
 import {ParsedArgs} from 'minimist';
 
 const APK_FILE_PARAM = '--apkFile';
@@ -23,12 +23,12 @@ const DEFAULT_APK_FILE = './app-release-signed.apk';
 const PARAMETERS_TO_IGNORE = ['--verbose', '-r'];
 
 export async function install(
-    args: ParsedArgs, config: Config, log = new Log('install')): Promise<boolean> {
+    args: ParsedArgs, config: Config, log: Log = new ConsoleLog('install')): Promise<boolean> {
   const jdkHelper = new JdkHelper(process, config);
   const androidSdkTools = new AndroidSdkTools(process, config, jdkHelper, log);
   const apkFile = args.apkFile || DEFAULT_APK_FILE;
   if (args.verbose) {
-    log.verbose = true;
+    log.setVerbose(true);
   }
 
   // parameter 0 would be the path to 'node', followed by `bubblewrap.js` at 1, then `install` at
diff --git a/packages/cli/src/lib/cmds/validate.ts b/packages/cli/src/lib/cmds/validate.ts
index 71d4a16b..db91e407 100644
--- a/packages/cli/src/lib/cmds/validate.ts
+++ b/packages/cli/src/lib/cmds/validate.ts
@@ -15,11 +15,11 @@
  */
 
 import {PwaValidator} from '@bubblewrap/validator';
-import {Log} from '@bubblewrap/core';
+import {ConsoleLog} from '@bubblewrap/core';
 import {ParsedArgs} from 'minimist';
 import {printValidationResult} from '../pwaValidationHelper';
 
-const log = new Log('validate');
+const log = new ConsoleLog('validate');
 
 /**
  * Runs the PwaValidator to check a given URL agains the Quality criteria. More information on the
diff --git a/packages/cli/src/lib/cmds/version.ts b/packages/cli/src/lib/cmds/version.ts
index f3ed01f2..f741668f 100644
--- a/packages/cli/src/lib/cmds/version.ts
+++ b/packages/cli/src/lib/cmds/version.ts
@@ -16,9 +16,9 @@
 
 import * as fs from 'fs';
 import * as path from 'path';
-import {Log} from '@bubblewrap/core';
+import {Log, ConsoleLog} from '@bubblewrap/core';
 
-export async function version(log = new Log('version')): Promise<boolean> {
+export async function version(log: Log = new ConsoleLog('version')): Promise<boolean> {
   const packageJsonFile = path.join(__dirname, '../../../package.json');
   const packageJsonContents = await (await fs.promises.readFile(packageJsonFile)).toString();
   const packageJson = JSON.parse(packageJsonContents);
diff --git a/packages/cli/src/lib/config.ts b/packages/cli/src/lib/config.ts
index 7a650bb3..367d3f7f 100644
--- a/packages/cli/src/lib/config.ts
+++ b/packages/cli/src/lib/config.ts
@@ -17,7 +17,7 @@
 
 import {join} from 'path';
 import {homedir} from 'os';
-import {Config, Log} from '@bubblewrap/core';
+import {Config, Log, ConsoleLog} from '@bubblewrap/core';
 import * as inquirer from 'inquirer';
 import {existsSync} from 'fs';
 import {promises as fsPromises} from 'fs';
@@ -44,7 +44,7 @@ async function createConfig(): Promise<Config> {
   return new Config(result.jdkPath, result.androidSdkPath);
 }
 
-async function renameConfigIfNeeded(log = new Log('config')): Promise<void> {
+async function renameConfigIfNeeded(log: Log = new ConsoleLog('config')): Promise<void> {
   if (existsSync(DEFAULT_CONFIG_FILE_PATH)) return;
   // No new named config file found.
   if (!existsSync(LEGACY_CONFIG_FILE_PATH)) return;
diff --git a/packages/core/package-lock.json b/packages/core/package-lock.json
index a8f7450e..355df312 100644
--- a/packages/core/package-lock.json
+++ b/packages/core/package-lock.json
@@ -368,11 +368,6 @@
         "rxjs": "^6.4.0"
       }
     },
-    "@types/jasmine": {
-      "version": "3.5.11",
-      "resolved": "https://registry.npmjs.org/@types/jasmine/-/jasmine-3.5.11.tgz",
-      "integrity": "sha512-fg1rOd/DehQTIJTifGqGVY6q92lDgnLfs7C6t1ccSwQrMyoTGSoH6wWzhJDZb6ezhsdwAX4EIBLe8w5fXWmEng=="
-    },
     "@types/lodash": {
       "version": "4.14.157",
       "resolved": "https://registry.npmjs.org/@types/lodash/-/lodash-4.14.157.tgz",
@@ -389,7 +384,8 @@
     "@types/mime-types": {
       "version": "2.1.0",
       "resolved": "https://registry.npmjs.org/@types/mime-types/-/mime-types-2.1.0.tgz",
-      "integrity": "sha1-nKUs2jY/aZxpRmwqbM2q2RPqenM="
+      "integrity": "sha1-nKUs2jY/aZxpRmwqbM2q2RPqenM=",
+      "dev": true
     },
     "@types/minipass": {
       "version": "2.2.0",
diff --git a/packages/core/package.json b/packages/core/package.json
index 41fcf9e9..85251060 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -48,4 +48,4 @@
     "tar": "^6.0.2",
     "valid-url": "^1.0.9"
   }
-}
+}
\ No newline at end of file
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 19d2c2f9..de9bff1c 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -17,7 +17,7 @@
 import {AndroidSdkTools} from './lib/androidSdk/AndroidSdkTools';
 import {Config} from './lib/Config';
 import {GradleWrapper} from './lib/GradleWrapper';
-import Log from './lib/Log';
+import {Log, ConsoleLog} from './lib/Log';
 import {JarSigner} from './lib/jdk/JarSigner';
 import {JdkHelper} from './lib/jdk/JdkHelper';
 import {KeyTool} from './lib/jdk/KeyTool';
@@ -36,6 +36,7 @@ export {AndroidSdkTools,
   JdkHelper,
   KeyTool,
   Log,
+  ConsoleLog,
   TwaGenerator,
   TwaManifest,
   DisplayMode,
diff --git a/packages/core/src/lib/Log.ts b/packages/core/src/lib/Log.ts
index 796bc7ff..beef5037 100644
--- a/packages/core/src/lib/Log.ts
+++ b/packages/core/src/lib/Log.ts
@@ -14,10 +14,45 @@
  *  limitations under the License.
  */
 
+/**
+ * An interface for loggers.
+ */
+export interface Log {
+
+  /**
+   * Prints a debug message to the Log. Message is ignored if the Log is not set to verbose.
+   * @param message the message the be printed.
+   * @param args extra arguments for the console.
+   */
+  debug(message: string, ...args: string[]): void;
+
+  /**
+   * Prints an info message to the Log. Message is ignored if the Log is not set to verbose.
+   * @param message The message the be printed.
+   * @param args Extra arguments for the console.
+   */
+  info(message: string, ...args: string[]): void;
+
+  /**
+   * Prints an warning message to the Log. Message is ignored if the Log is not set to verbose.
+   * @param message The message the be printed.
+   * @param args Extra arguments for the console.
+   */
+  warn(message: string, ...args: string[]): void;
+  /**
+   * Prints an error message to the Log. Message is ignored if the Log is not set to verbose.
+   * @param message The message the be printed.
+   * @param args Extra arguments for the console.
+   */
+  error(message: string, ...args: string[]): void;
+
+  setVerbose(verbose: boolean): void;
+};
+
 /**
  * An utility class to print nice Log messages.
  */
-export default class Log {
+export class ConsoleLog implements Log {
   private tag: string;
   private prefix: string;
   private output: Console;
@@ -29,9 +64,9 @@ export default class Log {
 
   /**
    * Creates a new Log instance
-   * @param tag the tag used when logging. Printed at the beggining of a log message.
-   * @param verbose if the Log is verbose. Debug messages are only printed on verbose logs.
-   * @param output where to output the log messages.
+   * @param tag The tag used when logging. Printed at the beggining of a log message.
+   * @param verbose If the Log is verbose. Debug messages are only printed on verbose logs.
+   * @param output Where to output the log messages.
    */
   constructor(tag = '', verbose = false, output = console) {
     this.tag = tag;
@@ -41,9 +76,9 @@ export default class Log {
   }
 
   /**
-   * Prints a debug message to the Log. message is ignored if the Log is not set to verbose.
-   * @param message the message the be printed.
-   * @param args extra arguments for the console.
+   * Prints a debug message to the Log. Message is ignored if the Log is not set to verbose.
+   * @param message The message the be printed.
+   * @param args Extra arguments for the console.
    */
   debug(message: string, ...args: string[]): void {
     if (!this.verbose) {
@@ -53,27 +88,27 @@ export default class Log {
   }
 
   /**
-   * Prints an info message to the Log. message is ignored if the Log is not set to verbose.
-   * @param message the message the be printed.
-   * @param args extra arguments for the console.
+   * Prints an info message to the Log. Message is ignored if the Log is not set to verbose.
+   * @param message The message the be printed.
+   * @param args Extra arguments for the console.
    */
   info(message: string, ...args: string[]): void {
     this.log(this.output.log, message, ...args);
   }
 
   /**
-   * Prints an warning message to the Log. message is ignored if the Log is not set to verbose.
-   * @param message the message the be printed.
-   * @param args extra arguments for the console.
+   * Prints an warning message to the Log. Message is ignored if the Log is not set to verbose.
+   * @param message The message the be printed.
+   * @param args Extra arguments for the console.
    */
   warn(message: string, ...args: string[]): void {
     this.log(this.output.warn, this.yellow('WARNING ' + message), ...args);
   }
 
   /**
-   * Prints an error message to the Log. message is ignored if the Log is not set to verbose.
-   * @param message the message the be printed.
-   * @param args extra arguments for the console.
+   * Prints an error message to the Log. Message is ignored if the Log is not set to verbose.
+   * @param message The message the be printed.
+   * @param args Extra arguments for the console.
    */
   error(message: string, ...args: string[]): void {
     this.output.error('\n');
@@ -81,15 +116,23 @@ export default class Log {
     this.output.error('\n');
   }
 
+  /**
+   * Sets the verbose.
+   * @param verbose The verbose value to set.
+   */
+  setVerbose(verbose: boolean): void {
+    this.verbose = verbose;
+  }
+
   /**
    * Creates a new Log using the same output and verbositity of the current Log.
-   * @param newTag the tag the be used on the new Log instance.
+   * @param newTag The tag the be used on the new Log instance.
    */
-  newLog(newTag: string): Log {
+  newLog(newTag: string): ConsoleLog {
     if (this.tag) {
       newTag = this.tag + ' ' + newTag;
     }
-    return new Log(newTag, this.verbose, this.output);
+    return new ConsoleLog(newTag, this.verbose, this.output);
   }
 
   private log(fn: Function, message: string, ...args: string[]): void {
diff --git a/packages/core/src/lib/TwaGenerator.ts b/packages/core/src/lib/TwaGenerator.ts
index 88463870..c1c92dd4 100644
--- a/packages/core/src/lib/TwaGenerator.ts
+++ b/packages/core/src/lib/TwaGenerator.ts
@@ -21,7 +21,7 @@ import {template} from 'lodash';
 import {promisify} from 'util';
 import {TwaManifest} from './TwaManifest';
 import {ShortcutInfo} from './ShortcutInfo';
-import Log from './Log';
+import {Log, ConsoleLog} from './Log';
 import {ImageHelper, IconDefinition} from './ImageHelper';
 
 const COPY_FILE_LIST = [
@@ -158,7 +158,7 @@ class Progress {
 export class TwaGenerator {
   private imageHelper = new ImageHelper();
 
-  constructor(private log = new Log('twa-generator')) {}
+  constructor(private log: Log = new ConsoleLog('twa-generator')) {}
 
   // Ensures targetDir exists and copies a file from sourceDir to target dir.
   private async copyStaticFile(
diff --git a/packages/core/src/lib/TwaManifest.ts b/packages/core/src/lib/TwaManifest.ts
index f527324c..cb8073b8 100644
--- a/packages/core/src/lib/TwaManifest.ts
+++ b/packages/core/src/lib/TwaManifest.ts
@@ -20,7 +20,7 @@ import * as fs from 'fs';
 import fetch from 'node-fetch';
 import {findSuitableIcon, generatePackageId, validateNotEmpty} from './util';
 import Color = require('color');
-import Log from './Log';
+import {ConsoleLog} from './Log';
 import {WebManifestIcon, WebManifestJson} from './types/WebManifest';
 import {ShortcutInfo} from './ShortcutInfo';
 
@@ -108,7 +108,7 @@ export class TwaManifest {
   fallbackType: FallbackType;
   enableSiteSettingsShortcut: boolean;
 
-  private static log: Log = new Log('twa-manifest');
+  private static log = new ConsoleLog('twa-manifest');
 
   constructor(data: TwaManifestJson) {
     this.packageId = data.packageId;
diff --git a/packages/core/src/lib/androidSdk/AndroidSdkTools.ts b/packages/core/src/lib/androidSdk/AndroidSdkTools.ts
index d843ae07..26219e52 100644
--- a/packages/core/src/lib/androidSdk/AndroidSdkTools.ts
+++ b/packages/core/src/lib/androidSdk/AndroidSdkTools.ts
@@ -19,7 +19,7 @@ import * as path from 'path';
 import util = require('../util');
 import {Config} from '../Config';
 import {JdkHelper} from '../jdk/JdkHelper';
-import Log from '../../lib/Log';
+import {Log, ConsoleLog} from '../../lib/Log';
 
 const BUILD_TOOLS_VERSION = '29.0.2';
 
@@ -40,7 +40,7 @@ export class AndroidSdkTools {
    * @param {jdkHelper} jdkHelper the JDK information to be used by the Android SDK
    */
   constructor(process: NodeJS.Process, config: Config, jdkHelper: JdkHelper,
-       readonly log = new Log('AndroidSdkTools')) {
+       readonly log: Log = new ConsoleLog('AndroidSdkTools')) {
     if (!fs.existsSync(config.androidSdkPath)) {
       throw new Error(`androidSdkPath does not exist: ${config.androidSdkPath}`);
     }
diff --git a/packages/core/src/lib/jdk/KeyTool.ts b/packages/core/src/lib/jdk/KeyTool.ts
index 4f85e715..1a1180f9 100644
--- a/packages/core/src/lib/jdk/KeyTool.ts
+++ b/packages/core/src/lib/jdk/KeyTool.ts
@@ -17,7 +17,7 @@
 import {existsSync, promises} from 'fs';
 import {execute} from '../util';
 import {JdkHelper} from './JdkHelper';
-import Log from '../Log';
+import {Log, ConsoleLog} from '../Log';
 
 export interface KeyInfo {
   fingerprints: Map<string, string>;
@@ -44,7 +44,7 @@ export class KeyTool {
   private jdkHelper: JdkHelper;
   private log: Log;
 
-  constructor(jdkHelper: JdkHelper, log = new Log('keytool')) {
+  constructor(jdkHelper: JdkHelper, log: Log = new ConsoleLog('keytool')) {
     this.jdkHelper = jdkHelper;
     this.log = log;
   }
diff --git a/packages/core/src/lib/util.ts b/packages/core/src/lib/util.ts
index a420aa62..c0853b5b 100644
--- a/packages/core/src/lib/util.ts
+++ b/packages/core/src/lib/util.ts
@@ -21,7 +21,7 @@ import {promisify} from 'util';
 import {exec, execFile, spawn} from 'child_process';
 import {x as extractTar} from 'tar';
 import {WebManifestIcon} from './types/WebManifest';
-import Log from './Log';
+import {Log} from './Log';
 import {lookup} from 'mime-types';
 
 const execPromise = promisify(exec);
diff --git a/packages/core/src/spec/lib/androidSdk/AndroidSdkToolsSpec.ts b/packages/core/src/spec/lib/androidSdk/AndroidSdkToolsSpec.ts
index 9a4856c3..8fa507af 100644
--- a/packages/core/src/spec/lib/androidSdk/AndroidSdkToolsSpec.ts
+++ b/packages/core/src/spec/lib/androidSdk/AndroidSdkToolsSpec.ts
@@ -19,7 +19,7 @@ import {JdkHelper} from '../../../lib/jdk/JdkHelper';
 import {AndroidSdkTools} from '../../../lib/androidSdk/AndroidSdkTools';
 import util = require('../../../lib/util');
 import * as fs from 'fs';
-import {Log} from '../../..';
+import {ConsoleLog} from '../../..';
 
 function buildMockConfig(platform: string): Config {
   if (platform === 'linux' || platform == 'darwin') {
@@ -179,7 +179,7 @@ describe('AndroidSdkTools', () => {
         const config = buildMockConfig(test.platform);
         const process = buildMockProcess(test.platform);
         const jdkHelper = new JdkHelper(process, config);
-        const log = new Log('test');
+        const log = new ConsoleLog('test');
         const androidSdkTools = new AndroidSdkTools(process, config, jdkHelper, log);
         spyOn(util, 'execute').and.stub();
         await androidSdkTools.install('app-release-signed.apk');
@@ -244,7 +244,7 @@ describe('AndroidSdkTools', () => {
         const config = buildMockConfig(test.platform);
         const process = buildMockProcess(test.platform);
         const jdkHelper = new JdkHelper(process, config);
-        const log = new Log('test');
+        const log = new ConsoleLog('test');
         const androidSdkTools = new AndroidSdkTools(process, config, jdkHelper, log);
         spyOn(util, 'executeFile').and.stub();
         await androidSdkTools.apksigner(