diff --git a/test/common/README.md b/test/common/README.md
index ac1877d908a86c..b8d9af2fcf70f5 100644
--- a/test/common/README.md
+++ b/test/common/README.md
@@ -50,12 +50,6 @@ Platform normalizes the `dd` command
 
 Check if there is more than 1gb of total memory.
 
-### envPlus(additionalEnv)
-* return [<Object>]
-
-Returns `process.env` plus `additionalEnv`. Used to pass a temporarily modified
-environment to a child process.
-
 ### expectsError([fn, ]settings[, exact])
 * `fn` [<Function>] a function that should throw.
 * `settings` [<Object>]
diff --git a/test/common/index.js b/test/common/index.js
index 8d01c6c8984aec..8175474818b9dc 100644
--- a/test/common/index.js
+++ b/test/common/index.js
@@ -182,10 +182,6 @@ if (exports.isLinux) {
   ];
 }
 
-exports.envPlus = function(additionalEnv) {
-  return Object.assign({}, process.env, additionalEnv);
-};
-
 Object.defineProperty(exports, 'inFreeBSDJail', {
   get: function() {
     if (inFreeBSDJail !== null) return inFreeBSDJail;
diff --git a/test/parallel/test-benchmark-crypto.js b/test/parallel/test-benchmark-crypto.js
index d02af4b2e9ac17..3675c38b9ea280 100644
--- a/test/parallel/test-benchmark-crypto.js
+++ b/test/parallel/test-benchmark-crypto.js
@@ -27,7 +27,7 @@ const argv = ['--set', 'algo=sha256',
               '--set', 'writes=1',
               'crypto'];
 
-const child = fork(runjs, argv, { env: common.envPlus({
+const child = fork(runjs, argv, { env: Object.assign({}, process.env, {
   NODEJS_BENCHMARK_ZERO_ALLOWED: 1 }) });
 
 child.on('exit', (code, signal) => {
diff --git a/test/parallel/test-benchmark-timers.js b/test/parallel/test-benchmark-timers.js
index 12eedf027fca8a..991ffda7186e72 100644
--- a/test/parallel/test-benchmark-timers.js
+++ b/test/parallel/test-benchmark-timers.js
@@ -1,6 +1,6 @@
 'use strict';
 
-const common = require('../common');
+require('../common');
 
 // Minimal test for timers benchmarks. This makes sure the benchmarks aren't
 // horribly broken but nothing more than that.
@@ -15,9 +15,10 @@ const argv = ['--set', 'type=depth',
               '--set', 'thousands=0.001',
               'timers'];
 
-const child = fork(runjs, argv, { env: common.envPlus({
-  NODEJS_BENCHMARK_ZERO_ALLOWED: 1 }) });
+const env = Object.assign({}, process.env,
+                          { NODEJS_BENCHMARK_ZERO_ALLOWED: 1 });
 
+const child = fork(runjs, argv, { env });
 child.on('exit', (code, signal) => {
   assert.strictEqual(code, 0);
   assert.strictEqual(signal, null);
diff --git a/test/parallel/test-child-process-env.js b/test/parallel/test-child-process-env.js
index c797233bf5d0ec..4582c48fda5db1 100644
--- a/test/parallel/test-child-process-env.js
+++ b/test/parallel/test-child-process-env.js
@@ -34,9 +34,11 @@ Object.setPrototypeOf(env, {
 
 let child;
 if (common.isWindows) {
-  child = spawn('cmd.exe', ['/c', 'set'], common.envPlus({ env: env }));
+  child = spawn('cmd.exe', ['/c', 'set'],
+                Object.assign({}, process.env, { env: env }));
 } else {
-  child = spawn('/usr/bin/env', [], common.envPlus({ env: env }));
+  child = spawn('/usr/bin/env', [],
+                Object.assign({}, process.env, { env: env }));
 }
 
 
diff --git a/test/parallel/test-child-process-exec-env.js b/test/parallel/test-child-process-exec-env.js
index f13af9e1f75587..c34fdb7b49a161 100644
--- a/test/parallel/test-child-process-exec-env.js
+++ b/test/parallel/test-child-process-exec-env.js
@@ -44,7 +44,9 @@ function after(err, stdout, stderr) {
 if (!common.isWindows) {
   child = exec('/usr/bin/env', { env: { 'HELLO': 'WORLD' } }, after);
 } else {
-  child = exec('set', { env: common.envPlus({ 'HELLO': 'WORLD' }) }, after);
+  child = exec('set',
+               { env: Object.assign({}, process.env, { 'HELLO': 'WORLD' }) },
+               after);
 }
 
 child.stdout.setEncoding('utf8');
diff --git a/test/parallel/test-child-process-spawn-shell.js b/test/parallel/test-child-process-spawn-shell.js
index 244f61807cedcf..e9a753e91a4e48 100644
--- a/test/parallel/test-child-process-spawn-shell.js
+++ b/test/parallel/test-child-process-spawn-shell.js
@@ -50,7 +50,7 @@ command.on('close', common.mustCall((code, signal) => {
 
 // Verify that the environment is properly inherited
 const env = cp.spawn(`"${process.execPath}" -pe process.env.BAZ`, {
-  env: common.envPlus({ BAZ: 'buzz' }),
+  env: Object.assign({}, process.env, { BAZ: 'buzz' }),
   encoding: 'utf8',
   shell: true
 });
diff --git a/test/parallel/test-child-process-spawnsync-env.js b/test/parallel/test-child-process-spawnsync-env.js
index 4e531e57b620a1..c8e11b5067c7d1 100644
--- a/test/parallel/test-child-process-spawnsync-env.js
+++ b/test/parallel/test-child-process-spawnsync-env.js
@@ -20,7 +20,7 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 'use strict';
-const common = require('../common');
+require('../common');
 const assert = require('assert');
 const cp = require('child_process');
 
@@ -29,7 +29,7 @@ if (process.argv[2] === 'child') {
 } else {
   const expected = 'bar';
   const child = cp.spawnSync(process.execPath, [__filename, 'child'], {
-    env: common.envPlus({ foo: expected })
+    env: Object.assign(process.env, { foo: expected })
   });
 
   assert.strictEqual(child.stdout.toString().trim(), expected);
diff --git a/test/parallel/test-child-process-spawnsync-shell.js b/test/parallel/test-child-process-spawnsync-shell.js
index 34d9c9a7d2cc39..f0838ae116e3be 100644
--- a/test/parallel/test-child-process-spawnsync-shell.js
+++ b/test/parallel/test-child-process-spawnsync-shell.js
@@ -37,7 +37,7 @@ assert.strictEqual(command.stdout.toString().trim(), 'bar');
 
 // Verify that the environment is properly inherited
 const env = cp.spawnSync(`"${process.execPath}" -pe process.env.BAZ`, {
-  env: common.envPlus({ BAZ: 'buzz' }),
+  env: Object.assign({}, process.env, { BAZ: 'buzz' }),
   shell: true
 });
 
diff --git a/test/parallel/test-cli-node-options.js b/test/parallel/test-cli-node-options.js
index bd84ddf855fbdd..f52497e80839cb 100644
--- a/test/parallel/test-cli-node-options.js
+++ b/test/parallel/test-cli-node-options.js
@@ -29,7 +29,8 @@ disallow('--');
 disallow('--no_warnings'); // Node options don't allow '_' instead of '-'.
 
 function disallow(opt) {
-  const options = { env: common.envPlus({ NODE_OPTIONS: opt }) };
+  const options = { env: Object.assign({}, process.env,
+                                       { NODE_OPTIONS: opt }) };
   exec(process.execPath, options, common.mustCall(function(err) {
     const message = err.message.split(/\r?\n/)[1];
     const expect = `${process.execPath}: ${opt} is not allowed in NODE_OPTIONS`;
@@ -71,7 +72,7 @@ function expect(opt, want) {
   const printB = require.resolve('../fixtures/printB.js');
   const argv = [printB];
   const opts = {
-    env: common.envPlus({ NODE_OPTIONS: opt }),
+    env: Object.assign({}, process.env, { NODE_OPTIONS: opt }),
     maxBuffer: 1000000000,
   };
   exec(process.execPath, argv, opts, common.mustCall(function(err, stdout) {
diff --git a/test/parallel/test-crypto-fips.js b/test/parallel/test-crypto-fips.js
index 6abe3c75cdb98c..da2dd7b0ba8765 100644
--- a/test/parallel/test-crypto-fips.js
+++ b/test/parallel/test-crypto-fips.js
@@ -63,7 +63,7 @@ testHelper(
   [],
   FIPS_DISABLED,
   'require("crypto").fips',
-  common.envPlus({ 'OPENSSL_CONF': '' }));
+  Object.assign({}, process.env, { 'OPENSSL_CONF': '' }));
 
 // --enable-fips should turn FIPS mode on
 testHelper(
@@ -108,7 +108,7 @@ if (!sharedOpenSSL()) {
     [],
     compiledWithFips() ? FIPS_ENABLED : FIPS_DISABLED,
     'require("crypto").fips',
-    common.envPlus({ 'OPENSSL_CONF': CNF_FIPS_ON }));
+    Object.assign({}, process.env, { 'OPENSSL_CONF': CNF_FIPS_ON }));
 
   // --openssl-config option should override OPENSSL_CONF
   testHelper(
@@ -116,7 +116,7 @@ if (!sharedOpenSSL()) {
     [`--openssl-config=${CNF_FIPS_ON}`],
     compiledWithFips() ? FIPS_ENABLED : FIPS_DISABLED,
     'require("crypto").fips',
-    common.envPlus({ 'OPENSSL_CONF': CNF_FIPS_OFF }));
+    Object.assign({}, process.env, { 'OPENSSL_CONF': CNF_FIPS_OFF }));
 }
 
 testHelper(
@@ -124,7 +124,7 @@ testHelper(
   [`--openssl-config=${CNF_FIPS_OFF}`],
   FIPS_DISABLED,
   'require("crypto").fips',
-  common.envPlus({ 'OPENSSL_CONF': CNF_FIPS_ON }));
+  Object.assign({}, process.env, { 'OPENSSL_CONF': CNF_FIPS_ON }));
 
 // --enable-fips should take precedence over OpenSSL config file
 testHelper(
@@ -140,7 +140,7 @@ testHelper(
   ['--enable-fips'],
   compiledWithFips() ? FIPS_ENABLED : OPTION_ERROR_STRING,
   'require("crypto").fips',
-  common.envPlus({ 'OPENSSL_CONF': CNF_FIPS_OFF }));
+  Object.assign({}, process.env, { 'OPENSSL_CONF': CNF_FIPS_OFF }));
 
 // --force-fips should take precedence over OpenSSL config file
 testHelper(
@@ -156,7 +156,7 @@ testHelper(
   ['--force-fips'],
   compiledWithFips() ? FIPS_ENABLED : OPTION_ERROR_STRING,
   'require("crypto").fips',
-  common.envPlus({ 'OPENSSL_CONF': CNF_FIPS_OFF }));
+  Object.assign({}, process.env, { 'OPENSSL_CONF': CNF_FIPS_OFF }));
 
 // setFipsCrypto should be able to turn FIPS mode on
 testHelper(
diff --git a/test/parallel/test-fs-readfile-error.js b/test/parallel/test-fs-readfile-error.js
index 9afa9ecbdc7354..e7c52f19a83d1c 100644
--- a/test/parallel/test-fs-readfile-error.js
+++ b/test/parallel/test-fs-readfile-error.js
@@ -33,7 +33,7 @@ const fixtures = require('../common/fixtures');
 function test(env, cb) {
   const filename = fixtures.path('test-fs-readfile-error.js');
   const execPath = `"${process.execPath}" "${filename}"`;
-  const options = { env: common.envPlus(env) };
+  const options = { env: Object.assign({}, process.env, env) };
   exec(execPath, options, common.mustCall((err, stdout, stderr) => {
     assert(err);
     assert.strictEqual(stdout, '');
diff --git a/test/parallel/test-http-server-stale-close.js b/test/parallel/test-http-server-stale-close.js
index be572dedeaf0ca..b72c2b55a02f25 100644
--- a/test/parallel/test-http-server-stale-close.js
+++ b/test/parallel/test-http-server-stale-close.js
@@ -20,7 +20,7 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 'use strict';
-const common = require('../common');
+require('../common');
 const http = require('http');
 const fork = require('child_process').fork;
 
@@ -44,7 +44,7 @@ if (process.env.NODE_TEST_FORK_PORT) {
   });
   server.listen(0, function() {
     fork(__filename, {
-      env: common.envPlus({
+      env: Object.assign({}, process.env, {
         NODE_TEST_FORK_PORT: this.address().port
       })
     });
diff --git a/test/parallel/test-icu-data-dir.js b/test/parallel/test-icu-data-dir.js
index 2b09e80a9f9fff..800e20c48bab03 100644
--- a/test/parallel/test-icu-data-dir.js
+++ b/test/parallel/test-icu-data-dir.js
@@ -17,7 +17,7 @@ const expected =
 }
 
 {
-  const env = common.envPlus({ NODE_ICU_DATA: '/' });
+  const env = Object.assign({}, process.env, { NODE_ICU_DATA: '/' });
   const child = spawnSync(process.execPath, ['-e', '0'], { env });
   assert(child.stderr.toString().includes(expected));
 }
diff --git a/test/parallel/test-inspector-open.js b/test/parallel/test-inspector-open.js
index 6db24f0687e449..a0d2eaf1f3415a 100644
--- a/test/parallel/test-inspector-open.js
+++ b/test/parallel/test-inspector-open.js
@@ -13,7 +13,8 @@ const url = require('url');
 if (process.env.BE_CHILD)
   return beChild();
 
-const child = fork(__filename, { env: common.envPlus({ BE_CHILD: 1 }) });
+const child = fork(__filename,
+                   { env: Object.assign({}, process.env, { BE_CHILD: 1 }) });
 
 child.once('message', common.mustCall((msg) => {
   assert.strictEqual(msg.cmd, 'started');
diff --git a/test/parallel/test-module-loading-globalpaths.js b/test/parallel/test-module-loading-globalpaths.js
index 8998b74953b74a..c12228ece763bf 100644
--- a/test/parallel/test-module-loading-globalpaths.js
+++ b/test/parallel/test-module-loading-globalpaths.js
@@ -36,7 +36,7 @@ if (process.argv[2] === 'child') {
   const testFixturesDir = path.join(common.fixturesDir,
                                     path.basename(__filename, '.js'));
 
-  const env = common.envPlus({});
+  const env = Object.assign({}, process.env);
   // Turn on module debug to aid diagnosing failures.
   env['NODE_DEBUG'] = 'module';
   // Unset NODE_PATH.
diff --git a/test/parallel/test-npm-install.js b/test/parallel/test-npm-install.js
index adb63e981949aa..9dcb5e8d1cda62 100644
--- a/test/parallel/test-npm-install.js
+++ b/test/parallel/test-npm-install.js
@@ -39,7 +39,7 @@ const pkgPath = path.join(installDir, 'package.json');
 
 fs.writeFileSync(pkgPath, pkgContent);
 
-const env = common.envPlus({
+const env = Object.assign({}, process.env, {
   PATH: path.dirname(process.execPath),
   NPM_CONFIG_PREFIX: path.join(npmSandbox, 'npm-prefix'),
   NPM_CONFIG_TMP: path.join(npmSandbox, 'npm-tmp'),
diff --git a/test/parallel/test-pending-deprecation.js b/test/parallel/test-pending-deprecation.js
index cb7d3d15754e1c..9b1fd5addfa0c6 100644
--- a/test/parallel/test-pending-deprecation.js
+++ b/test/parallel/test-pending-deprecation.js
@@ -37,7 +37,7 @@ switch (process.argv[2]) {
 
     // Test the NODE_PENDING_DEPRECATION environment var.
     fork(__filename, ['env'], {
-      env: common.envPlus({ NODE_PENDING_DEPRECATION: 1 }),
+      env: Object.assign({}, process.env, { NODE_PENDING_DEPRECATION: 1 }),
       silent: true
     }).on('exit', common.mustCall((code) => {
       assert.strictEqual(code, 0, message('NODE_PENDING_DEPRECATION'));
diff --git a/test/parallel/test-process-redirect-warnings-env.js b/test/parallel/test-process-redirect-warnings-env.js
index 35f0ec0b251f93..6748723cfe0bf3 100644
--- a/test/parallel/test-process-redirect-warnings-env.js
+++ b/test/parallel/test-process-redirect-warnings-env.js
@@ -16,7 +16,8 @@ common.refreshTmpDir();
 const warnmod = require.resolve(`${common.fixturesDir}/warnings.js`);
 const warnpath = path.join(common.tmpDir, 'warnings.txt');
 
-fork(warnmod, { env: common.envPlus({ NODE_REDIRECT_WARNINGS: warnpath }) })
+fork(warnmod, { env: Object.assign({}, process.env,
+                                   { NODE_REDIRECT_WARNINGS: warnpath }) })
   .on('exit', common.mustCall(() => {
     fs.readFile(warnpath, 'utf8', common.mustCall((err, data) => {
       assert.ifError(err);
diff --git a/test/parallel/test-repl-envvars.js b/test/parallel/test-repl-envvars.js
index 5545d1b4ea0ea5..d29e7b3574c1f2 100644
--- a/test/parallel/test-repl-envvars.js
+++ b/test/parallel/test-repl-envvars.js
@@ -36,7 +36,7 @@ const tests = [
 ];
 
 function run(test) {
-  const env = common.envPlus(test.env);
+  const env = Object.assign({}, process.env, test.env);
   const expected = test.expected;
   const opts = {
     terminal: true,
diff --git a/test/parallel/test-require-symlink.js b/test/parallel/test-require-symlink.js
index 7c00072ae1101c..4dd9bf51ed9213 100644
--- a/test/parallel/test-require-symlink.js
+++ b/test/parallel/test-require-symlink.js
@@ -60,7 +60,7 @@ function test() {
 
   // Also verify that symlinks works for setting preserve via env variables
   const childEnv = spawn(node, [linkScript], {
-    env: common.envPlus({ NODE_PRESERVE_SYMLINKS: '1' })
+    env: Object.assign({}, process.env, { NODE_PRESERVE_SYMLINKS: '1' })
   });
   childEnv.on('close', function(code, signal) {
     assert.strictEqual(code, 0);
diff --git a/test/parallel/test-stdin-script-child.js b/test/parallel/test-stdin-script-child.js
index 706d3d850c0e8e..06adc9e113eda7 100644
--- a/test/parallel/test-stdin-script-child.js
+++ b/test/parallel/test-stdin-script-child.js
@@ -5,7 +5,7 @@ const assert = require('assert');
 const { spawn } = require('child_process');
 for (const args of [[], ['-']]) {
   const child = spawn(process.execPath, args, {
-    env: common.envPlus({
+    env: Object.assign({}, process.env, {
       NODE_DEBUG: process.argv[2]
     })
   });
diff --git a/test/parallel/test-tls-env-bad-extra-ca.js b/test/parallel/test-tls-env-bad-extra-ca.js
index 8806adce6ac989..5c6e47d52a654a 100644
--- a/test/parallel/test-tls-env-bad-extra-ca.js
+++ b/test/parallel/test-tls-env-bad-extra-ca.js
@@ -21,7 +21,7 @@ const env = Object.assign({}, process.env, {
 });
 
 const opts = {
-  env: common.envPlus(env),
+  env: env,
   silent: true,
 };
 let stderr = '';
diff --git a/test/parallel/test-tls-env-extra-ca.js b/test/parallel/test-tls-env-extra-ca.js
index 91d9b97402d662..80d9cc9ec3ecef 100644
--- a/test/parallel/test-tls-env-extra-ca.js
+++ b/test/parallel/test-tls-env-extra-ca.js
@@ -32,7 +32,7 @@ const server = tls.createServer(options, common.mustCall(function(s) {
   s.end('bye');
   server.close();
 })).listen(0, common.mustCall(function() {
-  const env = common.envPlus({
+  const env = Object.assign({}, process.env, {
     CHILD: 'yes',
     PORT: this.address().port,
     NODE_EXTRA_CA_CERTS: fixtures.path('keys', 'ca1-cert.pem')
diff --git a/test/sequential/test-benchmark-http.js b/test/sequential/test-benchmark-http.js
index 42e9307c599dfc..b8d47fb8980db1 100644
--- a/test/sequential/test-benchmark-http.js
+++ b/test/sequential/test-benchmark-http.js
@@ -18,7 +18,8 @@ const path = require('path');
 
 const runjs = path.join(__dirname, '..', '..', 'benchmark', 'run.js');
 
-const env = common.envPlus({ NODEJS_BENCHMARK_ZERO_ALLOWED: 1 });
+const env = Object.assign({}, process.env,
+                          { NODEJS_BENCHMARK_ZERO_ALLOWED: 1 });
 
 const child = fork(runjs, ['--set', 'benchmarker=test-double',
                            '--set', 'c=1',