diff --git a/test/downloader/worker-pool.spec.ts b/test/downloader/worker-pool.spec.ts
index 9620c7bc..068e113e 100644
--- a/test/downloader/worker-pool.spec.ts
+++ b/test/downloader/worker-pool.spec.ts
@@ -1,7 +1,7 @@
 import {join} from 'path';
 // noinspection ES6PreferShortImport
-import type {WorkerInfo} from '../../src/downloader/worker-pool';
-import {WorkerPool} from '../../src/downloader/worker-pool';
+import type {WorkerInfo} from '../../src/downloader/worker-pool.js';
+import {WorkerPool} from '../../src/downloader/worker-pool.js';
 
 describe('worker-pool', function () {
   test('pool would work correctly', async () => {
diff --git a/test/life-cycle/detect-resource-type.spec.ts b/test/life-cycle/detect-resource-type.spec.ts
index 9841ea8c..fb0c28fd 100644
--- a/test/life-cycle/detect-resource-type.spec.ts
+++ b/test/life-cycle/detect-resource-type.spec.ts
@@ -2,8 +2,8 @@
 import {
   binaryExtension,
   detectResourceType
-} from '../../src/life-cycle/detect-resource-type';
-import {ResourceType} from '../../src/resource';
+} from '../../src/life-cycle/detect-resource-type.js';
+import {ResourceType} from '../../src/resource.js';
 
 describe('detect-resource-type', function () {
 
diff --git a/test/life-cycle/process-source-map.spec.ts b/test/life-cycle/process-source-map.spec.ts
index a69953b0..42dc5867 100644
--- a/test/life-cycle/process-source-map.spec.ts
+++ b/test/life-cycle/process-source-map.spec.ts
@@ -1,17 +1,17 @@
-import type {CreateResourceArgument, Resource} from '../../src/resource';
-import {createResource, ResourceType} from '../../src/resource';
+import type {CreateResourceArgument, Resource} from '../../src/resource.js';
+import {createResource, ResourceType} from '../../src/resource.js';
 import {
   isUriChar,
   processSourceMap,
   SOURCE_MAP_HEADER,
   sourceMapPrefix,
   X_SOURCE_MAP_HEADER
-} from '../../src/life-cycle/process-source-map';
-import type {DownloadResource} from '../../src/life-cycle/types';
+} from '../../src/life-cycle/process-source-map.js';
+import type {DownloadResource} from '../../src/life-cycle/types.js';
 // noinspection ES6PreferShortImport
-import type {PipelineExecutor} from '../../src/life-cycle/pipeline-executor';
-import type {StaticDownloadOptions} from '../../src/options';
-import type {Cheerio} from '../../src/types';
+import type {PipelineExecutor} from '../../src/life-cycle/pipeline-executor.js';
+import type {StaticDownloadOptions} from '../../src/options.js';
+import type {Cheerio} from '../../src/types.js';
 
 const fakeRes = (url: string): DownloadResource => {
   const arg: CreateResourceArgument = {
diff --git a/test/life-cycle/save-html-to-disk.spec.ts b/test/life-cycle/save-html-to-disk.spec.ts
index 2d2591fd..4d5c7994 100644
--- a/test/life-cycle/save-html-to-disk.spec.ts
+++ b/test/life-cycle/save-html-to-disk.spec.ts
@@ -1,16 +1,16 @@
 import {load} from 'cheerio';
 import * as fs from 'fs';
 // noinspection ES6PreferShortImport
-import {saveHtmlToDisk} from '../../src/life-cycle/save-html-to-disk';
+import {saveHtmlToDisk} from '../../src/life-cycle/save-html-to-disk.js';
 import {
   fakeOpt,
   fakePipeline,
   mockFs,
   mockModules,
   resHtml as res
-} from './save-mock-fs';
+} from './save-mock-fs.js';
 import {join} from 'path';
-import {ResourceType} from '../../src/resource';
+import {ResourceType} from '../../src/resource.js';
 
 mockModules();
 
diff --git a/test/life-cycle/save-mock-fs.ts b/test/life-cycle/save-mock-fs.ts
index d64e10b3..73e1bf13 100644
--- a/test/life-cycle/save-mock-fs.ts
+++ b/test/life-cycle/save-mock-fs.ts
@@ -3,14 +3,14 @@ import type {
   Resource,
   ResourceBody,
   ResourceEncoding
-} from '../../src/resource';
-import {createResource, ResourceType} from '../../src/resource';
-import type {DownloadResource} from '../../src/life-cycle/types';
-import type {StaticDownloadOptions} from '../../src/options';
+} from '../../src/resource.js';
+import {createResource, ResourceType} from '../../src/resource.js';
+import type {DownloadResource} from '../../src/life-cycle/types.js';
+import type {StaticDownloadOptions} from '../../src/options.js';
 // noinspection ES6PreferShortImport
-import type {PipelineExecutor} from '../../src/life-cycle/pipeline-executor';
+import type {PipelineExecutor} from '../../src/life-cycle/pipeline-executor.js';
 import {promises} from 'fs';
-import {toString} from '../../src/util';
+import {toString} from '../../src/util.js';
 
 export const fakeOpt = {
   concurrency: 0,
diff --git a/test/life-cycle/save-resource-to-disk.spec.ts b/test/life-cycle/save-resource-to-disk.spec.ts
index b910cd49..7cc8f287 100644
--- a/test/life-cycle/save-resource-to-disk.spec.ts
+++ b/test/life-cycle/save-resource-to-disk.spec.ts
@@ -1,8 +1,16 @@
 import * as fs from 'fs';
 // noinspection ES6PreferShortImport
-import {saveResourceToDisk} from '../../src/life-cycle/save-resource-to-disk';
+import {
+  saveResourceToDisk
+} from '../../src/life-cycle/save-resource-to-disk.js';
 import {join} from 'path';
-import {fakeOpt, fakePipeline, mockFs, mockModules, res} from './save-mock-fs';
+import {
+  fakeOpt,
+  fakePipeline,
+  mockFs,
+  mockModules,
+  res
+} from './save-mock-fs.js';
 
 mockModules();
 
diff --git a/test/life-cycle/skip-links.spec.ts b/test/life-cycle/skip-links.spec.ts
index 8259be94..25d9e9a3 100644
--- a/test/life-cycle/skip-links.spec.ts
+++ b/test/life-cycle/skip-links.spec.ts
@@ -1,7 +1,7 @@
 import {
   skipLinks,
   unProcessableUriSchemes
-} from '../../src/life-cycle/skip-links';
+} from '../../src/life-cycle/skip-links.js';
 
 describe('life-cycle/skip-links', function () {
   test('skip-un-processable-uri-schemes', () => {
diff --git a/test/resource.spec.ts b/test/resource.spec.ts
index 5fe9d38d..bbc032e7 100644
--- a/test/resource.spec.ts
+++ b/test/resource.spec.ts
@@ -3,7 +3,7 @@ import type {
   CreateResourceArgument,
   RawResource,
   Resource
-} from '../src/resource';
+} from '../src/resource.js';
 import {
   checkAbsoluteUri,
   createResource,
@@ -13,8 +13,8 @@ import {
   resolveFileUrl,
   ResourceType,
   urlOfSavePath
-} from '../src/resource';
-import URI = require('urijs');
+} from '../src/resource.js';
+import URI from 'urijs';
 
 describe('resource', function () {
   test('html-to-html-resource', () => {
diff --git a/test/sources.spec.ts b/test/sources.spec.ts
index d387e41b..b73d31d2 100644
--- a/test/sources.spec.ts
+++ b/test/sources.spec.ts
@@ -1,6 +1,6 @@
-import {sources} from '../src/sources';
+import {sources} from '../src/sources.js';
 import {load} from 'cheerio';
-import {ResourceType} from '../src/resource';
+import {ResourceType} from '../src/resource.js';
 
 describe('sources', function () {
   test('source should contains type', () => {
diff --git a/test/util.spec.ts b/test/util.spec.ts
index e23a7a3f..35e6a89d 100644
--- a/test/util.spec.ts
+++ b/test/util.spec.ts
@@ -2,10 +2,12 @@ import {
   arrayToMap,
   escapePath,
   importDefaultFromPath,
-  isSiteMap, isUrlHttp,
+  isSiteMap,
+  isUrlHttp,
   sleep,
-  toString, weakAssign
-} from '../src/util';
+  toString,
+  weakAssign
+} from '../src/util.js';
 import {join} from 'path';
 
 describe('util', function () {