diff --git a/package.json b/package.json
index 99058bc7..b068bfbb 100644
--- a/package.json
+++ b/package.json
@@ -17,10 +17,10 @@
     "formatters"
   ],
   "scripts": {
-    "test": "cross-env HTTP_PORT=0 LOG_LEVEL=fatal tap --no-coverage-report --no-cov --timeout 0 --test-regex=.test.js --test-ignore=node_modules",
-    "test:integration": "cross-env HTTP_PORT=0 LOG_LEVEL=fatal tap --no-coverage-report --no-cov --timeout 0 test/integration/**/*.test.js",
-    "test:unit": "cross-env HTTP_PORT=0 LOG_LEVEL=fatal tap --no-coverage-report --no-cov --timeout 0 test/*.test.js",
-    "test:tasks": "cross-env HTTP_PORT=0 LOG_LEVEL=fatal tap --no-coverage-report --no-cov --timeout 0 test/tasks/*.test.js",
+    "test": "cross-env HTTP_PORT=0 LOG_LEVEL=fatal tap --no-coverage-report --no-cov --timeout 0 --test-regex=.test.mjs --test-ignore=node_modules",
+    "test:integration": "cross-env HTTP_PORT=0 LOG_LEVEL=fatal tap --no-coverage-report --no-cov --timeout 0 test/integration/**/*.test.mjs",
+    "test:unit": "cross-env HTTP_PORT=0 LOG_LEVEL=fatal tap --no-coverage-report --no-cov --timeout 0 test/*.test.mjs",
+    "test:tasks": "cross-env HTTP_PORT=0 LOG_LEVEL=fatal tap --no-coverage-report --no-cov --timeout 0 test/tasks/*.test.mjs",
     "test:ci:integration": "npm run test:integration -- --jobs=1",
     "test:ci:unit": "npm run test:unit -- --jobs=1",
     "test:ci:tasks": "npm run test:tasks -- --jobs=1",
diff --git a/test/alias.test.js b/test/alias.test.mjs
similarity index 89%
rename from test/alias.test.js
rename to test/alias.test.mjs
index 195371de..7ccb0847 100644
--- a/test/alias.test.js
+++ b/test/alias.test.mjs
@@ -1,16 +1,18 @@
-/* eslint-disable no-param-reassign */
-
-'use strict';
-
-const os = require('os');
-const fs = require('fs').promises;
-const { join, basename } = require('path');
-const { test, beforeEach, afterEach } = require('tap');
-const EikService = require('@eik/service');
-const fastify = require('fastify');
-const { sink } = require('@eik/core');
-const { mockLogger } = require('./utils');
-const cli = require('..');
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { exec as execCallback } from 'child_process';
+import { join, basename } from 'path';
+import { mockLogger } from './utils.mjs';
+import { test, beforeEach, afterEach } from 'tap';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+import cli from '../classes/index.js';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 beforeEach(async (t) => {
     const server = fastify({ logger: false });
diff --git a/test/integration/alias.test.js b/test/integration/alias.test.mjs
similarity index 91%
rename from test/integration/alias.test.js
rename to test/integration/alias.test.mjs
index 63750187..6b8f7b68 100644
--- a/test/integration/alias.test.js
+++ b/test/integration/alias.test.mjs
@@ -1,21 +1,21 @@
-'use strict';
-
-/* eslint-disable no-param-reassign */
-
-const fastify = require('fastify');
-const fs = require('fs').promises;
-const os = require('os');
-const cp = require('child_process');
-const { join, basename } = require('path');
-const { test, beforeEach, afterEach } = require('tap');
-const fetch = require('node-fetch');
-const EikService = require('@eik/service');
-const { sink } = require('@eik/core');
-const cli = require('../..');
+import fastify from 'fastify';
+import { promises as fs } from 'node:fs';
+import os from 'node:os';
+import { exec as execCallback } from 'child_process';
+import { join, basename } from 'node:path';
+import { test, beforeEach, afterEach } from 'tap';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import cli from '../../classes/index.js';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 function exec(cmd) {
     return new Promise((resolve) => {
-        cp.exec(cmd, (error, stdout, stderr) => {
+        execCallback(cmd, (error, stdout, stderr) => {
             resolve({ error, stdout, stderr });
         });
     });
diff --git a/test/integration/init.test.js b/test/integration/init.test.mjs
similarity index 78%
rename from test/integration/init.test.js
rename to test/integration/init.test.mjs
index 77ba7ef3..4276ae41 100644
--- a/test/integration/init.test.js
+++ b/test/integration/init.test.mjs
@@ -1,15 +1,18 @@
-'use strict';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { test } from 'tap';
+import { join, basename } from 'path';
+import { readFileSync } from 'fs';
+import { exec as execCallback } from 'child_process';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
 
-const fs = require('fs').promises;
-const os = require('os');
-const { test } = require('tap');
-const { join, basename } = require('path');
-const { readFileSync } = require('fs');
-const cp = require('child_process');
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 function exec(cmd) {
     return new Promise((resolve) => {
-        cp.exec(cmd, (error, stdout, stderr) => {
+			execCallback(cmd, (error, stdout, stderr) => {
             resolve({ error, stdout, stderr });
         });
     });
@@ -22,7 +25,7 @@ test('Initializing a new eik.json file', async (t) => {
     const publishCmd = `${eik} init --cwd ${folder}`;
     await exec(publishCmd);
 
-    const assets = JSON.parse(readFileSync(join(folder, 'eik.json')));
+    const assets = JSON.parse(readFileSync(join(folder, 'eik.json'), { encoding: 'utf8' }));
 
     t.equal(assets.name, '', 'eik.json "name" field should be empty');
     t.equal(
@@ -45,7 +48,7 @@ test('Initializing a new eik.json file passing custom values', async (t) => {
         --server http://localhost:4001`;
     await exec(publishCmd.split('\n').join(' '));
 
-    const assets = JSON.parse(readFileSync(join(folder, 'eik.json')));
+    const assets = JSON.parse(readFileSync(join(folder, 'eik.json'), { encoding: 'utf8' }));
 
     t.equal(
         assets.name,
diff --git a/test/integration/integrity.test.js b/test/integration/integrity.test.mjs
similarity index 85%
rename from test/integration/integrity.test.js
rename to test/integration/integrity.test.mjs
index 90b8f09c..dd1fc1e1 100644
--- a/test/integration/integrity.test.js
+++ b/test/integration/integrity.test.mjs
@@ -1,19 +1,21 @@
-'use strict';
-
-/* eslint-disable no-param-reassign */
-const fastify = require('fastify');
-const fs = require('fs').promises;
-const os = require('os');
-const cp = require('child_process');
-const { join, basename } = require('path');
-const { test, beforeEach, afterEach } = require('tap');
-const EikService = require('@eik/service');
-const { sink } = require('@eik/core');
-const cli = require('../..');
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { exec as execCallback } from 'child_process';
+import { join, basename } from 'path';
+import { test, beforeEach, afterEach } from 'tap';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import cli from '../../classes/index.js';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 function exec(cmd) {
     return new Promise((resolve) => {
-        cp.exec(cmd, (error, stdout, stderr) => {
+			execCallback(cmd, (error, stdout, stderr) => {
             resolve({ error, stdout, stderr });
         });
     });
diff --git a/test/integration/login.test.js b/test/integration/login.test.mjs
similarity index 71%
rename from test/integration/login.test.js
rename to test/integration/login.test.mjs
index f4d4cde4..b6811c5a 100644
--- a/test/integration/login.test.js
+++ b/test/integration/login.test.mjs
@@ -1,20 +1,20 @@
-/* eslint-disable no-param-reassign */
-
-'use strict';
-
-// const util = require('util');
-const fastify = require('fastify');
-const fs = require('fs').promises;
-const os = require('os');
-const cp = require('child_process');
-const { join, basename } = require('path');
-const { test, beforeEach, afterEach } = require('tap');
-const EikService = require('@eik/service');
-const { sink } = require('@eik/core');
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { exec as execCallback } from 'child_process';
+import { join, basename } from 'path';
+import { test, beforeEach, afterEach } from 'tap';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 function exec(cmd) {
     return new Promise((resolve) => {
-        cp.exec(cmd, (error, stdout, stderr) => {
+        execCallback(cmd, (error, stdout, stderr) => {
             resolve({ error, stdout, stderr });
         });
     });
diff --git a/test/integration/map.test.js b/test/integration/map.test.mjs
similarity index 78%
rename from test/integration/map.test.js
rename to test/integration/map.test.mjs
index a27eafcb..64d6c882 100644
--- a/test/integration/map.test.js
+++ b/test/integration/map.test.mjs
@@ -1,20 +1,22 @@
-'use strict';
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { exec as execCallback } from 'child_process';
+import { join, basename } from 'path';
+import { test, beforeEach, afterEach } from 'tap';
+import fetch from 'node-fetch';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import cli from '../../classes/index.js';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
 
-/* eslint-disable no-param-reassign */
-const fastify = require('fastify');
-const fs = require('fs').promises;
-const os = require('os');
-const cp = require('child_process');
-const { join, basename } = require('path');
-const { test, beforeEach, afterEach } = require('tap');
-const fetch = require('node-fetch');
-const EikService = require('@eik/service');
-const { sink } = require('@eik/core');
-const cli = require('../..');
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 function exec(cmd) {
     return new Promise((resolve) => {
-        cp.exec(cmd, (error, stdout, stderr) => {
+        execCallback(cmd, (error, stdout, stderr) => {
             resolve({ error, stdout, stderr });
         });
     });
diff --git a/test/integration/meta.test.js b/test/integration/meta.test.mjs
similarity index 75%
rename from test/integration/meta.test.js
rename to test/integration/meta.test.mjs
index 83899c95..aa1a2f4e 100644
--- a/test/integration/meta.test.js
+++ b/test/integration/meta.test.mjs
@@ -1,19 +1,21 @@
-'use strict';
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { exec as execCallback } from 'child_process';
+import { join, basename } from 'path';
+import { test, beforeEach, afterEach } from 'tap';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import cli from '../../classes/index.js';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
 
-/* eslint-disable no-param-reassign */
-const fastify = require('fastify');
-const fs = require('fs').promises;
-const os = require('os');
-const cp = require('child_process');
-const { join, basename } = require('path');
-const { test, beforeEach, afterEach } = require('tap');
-const EikService = require('@eik/service');
-const { sink } = require('@eik/core');
-const cli = require('../..');
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 function exec(cmd) {
     return new Promise((resolve) => {
-        cp.exec(cmd, (error, stdout, stderr) => {
+			execCallback(cmd, (error, stdout, stderr) => {
             resolve({ error, stdout, stderr });
         });
     });
diff --git a/test/integration/package.test.js b/test/integration/package.test.mjs
similarity index 93%
rename from test/integration/package.test.js
rename to test/integration/package.test.mjs
index ec48cd90..7cdbd68c 100644
--- a/test/integration/package.test.js
+++ b/test/integration/package.test.mjs
@@ -1,20 +1,21 @@
-'use strict';
-
-/* eslint-disable no-param-reassign */
-const fastify = require('fastify');
-const fs = require('fs').promises;
-const os = require('os');
-const cp = require('child_process');
-const { join, basename } = require('path');
-const { test, beforeEach, afterEach } = require('tap');
-const fetch = require('node-fetch');
-const EikService = require('@eik/service');
-const { sink } = require('@eik/core');
-const cli = require('../..');
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { exec as execCallback } from 'child_process';
+import { join, basename } from 'path';
+import { test, beforeEach, afterEach } from 'tap';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import cli from '../../classes/index.js';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 function exec(cmd) {
     return new Promise((resolve) => {
-        cp.exec(cmd, (error, stdout, stderr) => {
+        execCallback(cmd, (error, stdout, stderr) => {
             resolve({ error, stdout, stderr });
         });
     });
diff --git a/test/integrity.test.js b/test/integrity.test.mjs
similarity index 75%
rename from test/integrity.test.js
rename to test/integrity.test.mjs
index 55ce4c0b..6bc58840 100644
--- a/test/integrity.test.js
+++ b/test/integrity.test.mjs
@@ -1,13 +1,17 @@
-/* eslint-disable no-param-reassign */
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { join, basename } from 'path';
+import { mockLogger } from './utils.mjs';
+import { test, beforeEach, afterEach } from 'tap';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+import cli from '../classes/index.js';
 
-'use strict';
-
-const { join } = require('path');
-const fastify = require('fastify');
-const { test, beforeEach, afterEach } = require('tap');
-const EikService = require('@eik/service');
-const { sink } = require('@eik/core');
-const cli = require('..');
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 beforeEach(async (t) => {
     const server = fastify({ logger: false });
diff --git a/test/login.test.js b/test/login.test.mjs
similarity index 72%
rename from test/login.test.js
rename to test/login.test.mjs
index e62e958d..27364524 100644
--- a/test/login.test.js
+++ b/test/login.test.mjs
@@ -1,13 +1,17 @@
-/* eslint-disable no-param-reassign */
-
-'use strict';
-
-const { test, beforeEach, afterEach } = require('tap');
-const fastify = require('fastify');
-const EikService = require('@eik/service');
-const { sink } = require('@eik/core');
-const { mockLogger } = require('./utils');
-const cli = require('..');
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { join, basename } from 'path';
+import { mockLogger } from './utils.mjs';
+import { test, beforeEach, afterEach } from 'tap';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+import cli from '../classes/index.js';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 beforeEach(async (t) => {
     const memSink = new sink.MEM();
diff --git a/test/meta.test.js b/test/meta.test.mjs
similarity index 76%
rename from test/meta.test.js
rename to test/meta.test.mjs
index 0d4a2c01..8fe80e44 100644
--- a/test/meta.test.js
+++ b/test/meta.test.mjs
@@ -1,16 +1,17 @@
-/* eslint-disable no-param-reassign */
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { join, basename } from 'path';
+import { mockLogger } from './utils.mjs';
+import { test, beforeEach, afterEach } from 'tap';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+import cli from '../classes/index.js';
 
-'use strict';
-
-const os = require('os');
-const fs = require('fs').promises;
-const { join, basename } = require('path');
-const fastify = require('fastify');
-const { test, beforeEach, afterEach } = require('tap');
-const EikService = require('@eik/service');
-const { sink } = require('@eik/core');
-const { mockLogger } = require('./utils');
-const cli = require('..');
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 beforeEach(async (t) => {
     const server = fastify({ logger: false });
diff --git a/test/publish-files-definitions.test.js b/test/publish-files-definitions.test.mjs
similarity index 93%
rename from test/publish-files-definitions.test.js
rename to test/publish-files-definitions.test.mjs
index 877e3dda..9816fc3f 100644
--- a/test/publish-files-definitions.test.js
+++ b/test/publish-files-definitions.test.mjs
@@ -1,14 +1,17 @@
-/* eslint-disable no-param-reassign */
-
-const os = require('os');
-const fs = require('fs').promises;
-const { join, basename } = require('path');
-const { test, beforeEach, afterEach } = require('tap');
-const fastify = require('fastify');
-const EikService = require('@eik/service');
-const { sink } = require('@eik/core');
-const { copySync } = require('fs-extra');
-const cli = require('../classes');
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { join, basename } from 'path';
+import { test, beforeEach, afterEach } from 'tap';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import fsExtra from 'fs-extra';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+import cli from '../classes/index.js';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 const config = (files, server, token, cwd) => ({
     logger: null,
@@ -37,7 +40,7 @@ beforeEach(async (t) => {
     });
 
     const cwd = await fs.mkdtemp(join(os.tmpdir(), basename(__filename)));
-    copySync(join(__dirname, './fixtures'), join(cwd, 'fixtures'));
+    fsExtra.copySync(join(__dirname, './fixtures'), join(cwd, 'fixtures'));
 
     t.context.server = server;
     t.context.address = address;
diff --git a/test/publish.map.test.js b/test/publish.map.test.mjs
similarity index 74%
rename from test/publish.map.test.js
rename to test/publish.map.test.mjs
index 4e515cf2..ab1d71ff 100644
--- a/test/publish.map.test.js
+++ b/test/publish.map.test.mjs
@@ -1,16 +1,17 @@
-/* eslint-disable no-param-reassign */
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { join, basename } from 'path';
+import { mockLogger } from './utils.mjs';
+import { test, beforeEach, afterEach } from 'tap';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+import cli from '../classes/index.js';
 
-'use strict';
-
-const os = require('os');
-const fs = require('fs').promises;
-const { join, basename } = require('path');
-const fastify = require('fastify');
-const { test, beforeEach, afterEach } = require('tap');
-const EikService = require('@eik/service');
-const { sink } = require('@eik/core');
-const { mockLogger } = require('./utils');
-const cli = require('..');
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 beforeEach(async (t) => {
     const memSink = new sink.MEM();
diff --git a/test/publish.package.test.js b/test/publish.package.test.mjs
similarity index 92%
rename from test/publish.package.test.js
rename to test/publish.package.test.mjs
index 1f9cb35e..cabc552b 100644
--- a/test/publish.package.test.js
+++ b/test/publish.package.test.mjs
@@ -1,16 +1,17 @@
-/* eslint-disable no-param-reassign */
-
-'use strict';
-
-const os = require('os');
-const fs = require('fs').promises;
-const { join, basename } = require('path');
-const { test, beforeEach, afterEach } = require('tap');
-const fastify = require('fastify');
-const EikService = require('@eik/service');
-const { sink } = require('@eik/core');
-const { mockLogger } = require('./utils');
-const cli = require('..');
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { join, basename } from 'path';
+import { mockLogger } from './utils.mjs';
+import { test, beforeEach, afterEach } from 'tap';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+import cli from '../classes/index.js';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 beforeEach(async (t) => {
     const memSink = new sink.MEM();
diff --git a/test/tasks/cleanup.test.js b/test/tasks/cleanup.test.mjs
similarity index 68%
rename from test/tasks/cleanup.test.js
rename to test/tasks/cleanup.test.mjs
index d0fff319..45fa6b5c 100644
--- a/test/tasks/cleanup.test.js
+++ b/test/tasks/cleanup.test.mjs
@@ -1,12 +1,13 @@
-/* eslint-disable no-param-reassign */
+import { promises as fs } from 'fs';
+import { join } from 'path';
+import { test, beforeEach, afterEach } from 'tap';
+import rimraf from 'rimraf';
+import CleanupTask from '../../classes/publish/package/tasks/cleanup.js';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
 
-'use strict';
-
-const fs = require('fs').promises;
-const { join } = require('path');
-const { test, beforeEach, afterEach } = require('tap');
-const rimraf = require('rimraf');
-const CleanupTask = require('../../classes/publish/package/tasks/cleanup');
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 beforeEach(async (t) => {
     const path = join(__dirname, '.eik');
diff --git a/test/utils.js b/test/utils.mjs
similarity index 85%
rename from test/utils.js
rename to test/utils.mjs
index c752acf6..04dec061 100644
--- a/test/utils.js
+++ b/test/utils.mjs
@@ -1,7 +1,3 @@
-/* eslint-disable no-underscore-dangle */
-
-'use strict';
-
 const mockLogger = () => {
     const logs = {
         fatal: '',
@@ -34,4 +30,4 @@ const mockLogger = () => {
     return { logs, logger };
 };
 
-module.exports.mockLogger = mockLogger;
+export { mockLogger };
diff --git a/test/utils.test.js b/test/utils.test.mjs
similarity index 87%
rename from test/utils.test.js
rename to test/utils.test.mjs
index 4a147fe1..1fdbfe80 100644
--- a/test/utils.test.js
+++ b/test/utils.test.mjs
@@ -1,14 +1,17 @@
-'use strict';
-
-const os = require('os');
-const { join, basename } = require('path');
-const fs = require('fs');
-const crypto = require('crypto');
-const { test } = require('tap');
-const fastify = require('fastify');
-const j = require('../utils/json');
-const h = require('../utils/hash');
-const f = require('../utils/http');
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { join, basename } from 'path';
+import { test, beforeEach, afterEach } from 'tap';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+import crypto from 'crypto';
+import j from '../utils/json/index.js';
+import h from '../utils/hash/index.js';
+import f from '../utils/http/index.js';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 test('calculate file hash', async (t) => {
     const hash = await h.file(join(__dirname, 'fixtures', 'client.js'));
@@ -235,14 +238,14 @@ test('fetch remote hash for a given version', async (t) => {
 });
 
 test('write JSON file - object - file relative to cwd', async (t) => {
-    const cwd = await fs.promises.mkdtemp(
+    const cwd = await fs.mkdtemp(
         join(os.tmpdir(), basename(__filename)),
     );
     await j.write(
         { version: '1.0.0', integrity: [] },
         { cwd, filename: '.eikrc' },
     );
-    const eikrc = fs.readFileSync(join(cwd, '.eikrc'));
+    const eikrc = await fs.readFile(join(cwd, '.eikrc'));
     const { version, integrity } = JSON.parse(eikrc);
 
     t.equal(version, '1.0.0', 'Version should be 1.0.0');
@@ -250,11 +253,11 @@ test('write JSON file - object - file relative to cwd', async (t) => {
 });
 
 test('write JSON file - object - file absolute path', async (t) => {
-    const cwd = await fs.promises.mkdtemp(
+    const cwd = await fs.mkdtemp(
         join(os.tmpdir(), basename(__filename)),
     );
     await j.write({ prop: 'val' }, { filename: join(cwd, 'test.json') });
-    const eikrc = fs.readFileSync(join(cwd, 'test.json'));
+    const eikrc = await fs.readFile(join(cwd, 'test.json'), { encoding: 'utf8' });
     const { prop } = JSON.parse(eikrc);
 
     t.equal(prop, 'val', 'Prop should equal val');
@@ -262,48 +265,49 @@ test('write JSON file - object - file absolute path', async (t) => {
 
 test('write JSON file - string - file relative path', async (t) => {
     await j.write({ prop: 'val' }, './test-using-relative.json');
-    const eikrc = fs.readFileSync(
+    const eikrc = await fs.readFile(
         join(__dirname, '../test-using-relative.json'),
+				{ encoding: 'utf8' },
     );
     const { prop } = JSON.parse(eikrc);
-    await fs.unlinkSync(join(__dirname, '../test-using-relative.json'));
+    await fs.unlink(join(__dirname, '../test-using-relative.json'));
 
     t.equal(prop, 'val', 'Prop should equal val');
 });
 
 test('write JSON file - string - file absolute path', async (t) => {
-    const cwd = await fs.promises.mkdtemp(
+    const cwd = await fs.mkdtemp(
         join(os.tmpdir(), basename(__filename)),
     );
     await j.write({ prop: 'val' }, join(cwd, 'test3.json'));
-    const eikrc = fs.readFileSync(join(cwd, 'test3.json'));
+    const eikrc = await fs.readFile(join(cwd, 'test3.json'), { encoding: 'utf8' });
     const { prop } = JSON.parse(eikrc);
 
     t.equal(prop, 'val', 'Prop should equal val');
 });
 
 test('read JSON file - object - file relative path', async (t) => {
-    const cwd = await fs.promises.mkdtemp(
+    const cwd = await fs.mkdtemp(
         join(os.tmpdir(), basename(__filename)),
     );
-    fs.writeFileSync(join(cwd, 'test3.json'), JSON.stringify({ key: 'val' }));
+    await fs.writeFile(join(cwd, 'test3.json'), JSON.stringify({ key: 'val' }));
     const json = await j.read({ cwd, filename: './test3.json' });
 
     t.equal(json.key, 'val', 'Key should equal val');
 });
 
 test('read JSON file - object - file absolute path', async (t) => {
-    const cwd = await fs.promises.mkdtemp(
+    const cwd = await fs.mkdtemp(
         join(os.tmpdir(), basename(__filename)),
     );
-    fs.writeFileSync(join(cwd, 'test3.json'), JSON.stringify({ key: 'val' }));
+    await fs.writeFile(join(cwd, 'test3.json'), JSON.stringify({ key: 'val' }));
     const json = await j.read({ filename: join(cwd, './test3.json') });
 
     t.equal(json.key, 'val', 'Key should equal val');
 });
 
 test('read JSON file - string - file relative path', async (t) => {
-    fs.writeFileSync(
+    await fs.writeFile(
         join(__dirname, '../test-read-json.json'),
         JSON.stringify({ key: 'val' }),
     );
@@ -313,10 +317,10 @@ test('read JSON file - string - file relative path', async (t) => {
 });
 
 test('read JSON file - string - file absolute path', async (t) => {
-    const cwd = await fs.promises.mkdtemp(
+    const cwd = await fs.mkdtemp(
         join(os.tmpdir(), basename(__filename)),
     );
-    fs.writeFileSync(
+    await fs.writeFile(
         join(cwd, './test-read-json-2.json'),
         JSON.stringify({ key: 'val' }),
     );
diff --git a/test/version.test.js b/test/version.test.mjs
similarity index 81%
rename from test/version.test.js
rename to test/version.test.mjs
index 370258fb..dfbff693 100644
--- a/test/version.test.js
+++ b/test/version.test.mjs
@@ -1,15 +1,17 @@
-/* eslint-disable no-param-reassign */
-
-'use strict';
-
-const fs = require('fs');
-const os = require('os');
-const { join, basename } = require('path');
-const { test, beforeEach, afterEach } = require('tap');
-const fastify = require('fastify');
-const EikService = require('@eik/service');
-const { sink } = require('@eik/core');
-const cli = require('..');
+import fastify from 'fastify';
+import { promises as fs } from 'fs';
+import os from 'os';
+import { join, basename } from 'path';
+import { mockLogger } from './utils.mjs';
+import { test, beforeEach, afterEach } from 'tap';
+import EikService from '@eik/service';
+import { sink } from '@eik/core';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+import cli from '../classes/index.js';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 beforeEach(async (t) => {
     const memSink = new sink.MEM();
@@ -26,7 +28,7 @@ beforeEach(async (t) => {
         key: 'change_me',
     });
 
-    const cwd = await fs.mkdtempSync(join(os.tmpdir(), basename(__filename)));
+    const cwd = await fs.mkdtemp(join(os.tmpdir(), basename(__filename)));
 
     t.context.server = server;
     t.context.address = address;