diff --git a/test/addons/symlinked-module/test.js b/test/addons/symlinked-module/test.js
index 98eec17d0c8c95..cbd01e938fe25f 100644
--- a/test/addons/symlinked-module/test.js
+++ b/test/addons/symlinked-module/test.js
@@ -30,5 +30,5 @@ const sub = require('./submodule');
   const mod = require(path.join(i, 'binding.node'));
   assert.notStrictEqual(mod, null);
   assert.strictEqual(mod.hello(), 'world');
-  sub.test(i);
+  sub.test(i); // Should not throw.
 });
diff --git a/test/internet/test-dns.js b/test/internet/test-dns.js
index dadf14c0be36b1..f1b7b4ff056833 100644
--- a/test/internet/test-dns.js
+++ b/test/internet/test-dns.js
@@ -579,11 +579,8 @@ process.on('exit', function() {
   assert.ok(getaddrinfoCallbackCalled);
 });
 
-
+// Should not throw.
 dns.lookup(addresses.INET6_HOST, 6, common.mustCall());
-
 dns.lookup(addresses.INET_HOST, {}, common.mustCall());
-
 dns.lookupService('0.0.0.0', '0', common.mustCall());
-
 dns.lookupService('0.0.0.0', 0, common.mustCall());
diff --git a/test/parallel/test-assert-deep.js b/test/parallel/test-assert-deep.js
index d9c9df5bb2c875..d0aacfdf516f4c 100644
--- a/test/parallel/test-assert-deep.js
+++ b/test/parallel/test-assert-deep.js
@@ -492,8 +492,8 @@ assertOnlyDeepEqual([1, , , 3], [1, , , 3, , , ]);
 
 // Handle NaN
 assert.throws(() => { assert.deepEqual(NaN, NaN); }, assert.AssertionError);
-{ assert.deepStrictEqual(NaN, NaN); }
-{ assert.deepStrictEqual({ a: NaN }, { a: NaN }); }
+assert.deepStrictEqual(NaN, NaN);
+assert.deepStrictEqual({ a: NaN }, { a: NaN });
 assert.deepStrictEqual([ 1, 2, NaN, 4 ], [ 1, 2, NaN, 4 ]);
 
 // Handle boxed primitives
diff --git a/test/parallel/test-buffer-alloc.js b/test/parallel/test-buffer-alloc.js
index 7f062f6b58c68c..20e91377cd7fdf 100644
--- a/test/parallel/test-buffer-alloc.js
+++ b/test/parallel/test-buffer-alloc.js
@@ -62,7 +62,7 @@ assert.throws(() => b.write('test', 'utf8', 0),
               /is no longer supported/);
 
 
-// try to create 0-length buffers
+// Try to create 0-length buffers. Should not throw.
 Buffer.from('');
 Buffer.from('', 'ascii');
 Buffer.from('', 'latin1');
@@ -107,7 +107,7 @@ b.copy(Buffer.alloc(1), 0, 2048, 2048);
   assert.strictEqual(writeTest.toString(), 'nodejs');
 }
 
-// Offset points to the end of the buffer
+// Offset points to the end of the buffer and does not throw.
 // (see https://github.com/nodejs/node/issues/8127).
 Buffer.alloc(1).write('', 1, 0);
 
@@ -992,10 +992,10 @@ common.expectsError(() => {
   assert.strictEqual(ubuf.buffer.byteLength, 10);
 }
 
-// Regression test
+// Regression test to verify that an empty ArrayBuffer does not throw.
 Buffer.from(new ArrayBuffer());
 
-// Test that ArrayBuffer from a different context is detected correctly
+// Test that ArrayBuffer from a different context is detected correctly.
 const arrayBuf = vm.runInNewContext('new ArrayBuffer()');
 Buffer.from(arrayBuf);
 Buffer.from({ buffer: arrayBuf });
diff --git a/test/parallel/test-buffer-bad-overload.js b/test/parallel/test-buffer-bad-overload.js
index ec2703341b2f38..63acb8ebfb6d49 100644
--- a/test/parallel/test-buffer-bad-overload.js
+++ b/test/parallel/test-buffer-bad-overload.js
@@ -2,7 +2,7 @@
 const common = require('../common');
 const assert = require('assert');
 
-Buffer.allocUnsafe(10);
+Buffer.allocUnsafe(10); // Should not throw.
 
 const err = common.expectsError({
   code: 'ERR_INVALID_ARG_TYPE',
@@ -14,4 +14,4 @@ assert.throws(function() {
   Buffer.from(10, 'hex');
 }, err);
 
-Buffer.from('deadbeaf', 'hex');
+Buffer.from('deadbeaf', 'hex'); // Should not throw.
diff --git a/test/parallel/test-buffer-constants.js b/test/parallel/test-buffer-constants.js
index dbb6186b6de5ce..f6f0dbddc39d3e 100644
--- a/test/parallel/test-buffer-constants.js
+++ b/test/parallel/test-buffer-constants.js
@@ -11,7 +11,7 @@ assert(MAX_STRING_LENGTH <= MAX_LENGTH);
 assert.throws(() => ' '.repeat(MAX_STRING_LENGTH + 1),
               /^RangeError: Invalid string length$/);
 
-' '.repeat(MAX_STRING_LENGTH);
+' '.repeat(MAX_STRING_LENGTH); // Should not throw.
 
 // Legacy values match:
 assert.strictEqual(kMaxLength, MAX_LENGTH);
diff --git a/test/parallel/test-buffer-copy.js b/test/parallel/test-buffer-copy.js
index 324613a04fe525..5c82f4de28dbee 100644
--- a/test/parallel/test-buffer-copy.js
+++ b/test/parallel/test-buffer-copy.js
@@ -92,7 +92,7 @@ const bb = Buffer.allocUnsafe(10);
 bb.fill('hello crazy world');
 
 
-// try to copy from before the beginning of b
+// Try to copy from before the beginning of b. Should not throw.
 b.copy(c, 0, 100, 10);
 
 // copy throws at negative sourceStart
diff --git a/test/parallel/test-buffer-sharedarraybuffer.js b/test/parallel/test-buffer-sharedarraybuffer.js
index 536c3939365d98..0252847c054c1d 100644
--- a/test/parallel/test-buffer-sharedarraybuffer.js
+++ b/test/parallel/test-buffer-sharedarraybuffer.js
@@ -22,8 +22,7 @@ arr2[1] = 6000;
 
 assert.deepStrictEqual(arr_buf, ar_buf);
 
-// Checks for calling Buffer.byteLength on a SharedArrayBuffer
-
+// Checks for calling Buffer.byteLength on a SharedArrayBuffer.
 assert.strictEqual(Buffer.byteLength(sab), sab.byteLength);
 
-Buffer.from({ buffer: sab });
+Buffer.from({ buffer: sab }); // Should not throw.
diff --git a/test/parallel/test-buffer-slice.js b/test/parallel/test-buffer-slice.js
index b55d082783cc28..6175370a9bccee 100644
--- a/test/parallel/test-buffer-slice.js
+++ b/test/parallel/test-buffer-slice.js
@@ -77,9 +77,8 @@ expectedSameBufs.forEach(([buf1, buf2]) => {
 
 const utf16Buf = Buffer.from('0123456789', 'utf16le');
 assert.deepStrictEqual(utf16Buf.slice(0, 6), Buffer.from('012', 'utf16le'));
-// try to slice a zero length Buffer
-// see https://github.com/joyent/node/issues/5881
-Buffer.alloc(0).slice(0, 1);
+// Try to slice a zero length Buffer.
+// See https://github.com/joyent/node/issues/5881
 assert.strictEqual(Buffer.alloc(0).slice(0, 1).length, 0);
 
 {
diff --git a/test/parallel/test-child-process-spawn-typeerror.js b/test/parallel/test-child-process-spawn-typeerror.js
index eede5fdd15d5c0..9855c0cfd99fa6 100644
--- a/test/parallel/test-child-process-spawn-typeerror.js
+++ b/test/parallel/test-child-process-spawn-typeerror.js
@@ -38,13 +38,13 @@ assert.throws(function() {
   child.on('error', common.mustNotCall());
 }, TypeError);
 
-// verify that valid argument combinations do not throw
+// Verify that valid argument combinations do not throw.
 spawn(cmd);
 spawn(cmd, []);
 spawn(cmd, {});
 spawn(cmd, [], {});
 
-// verify that invalid argument combinations throw
+// Verify that invalid argument combinations throw.
 assert.throws(function() {
   spawn();
 }, invalidFileMsg);
@@ -74,7 +74,7 @@ assert.throws(function() {
   spawn(cmd, [], 1);
 }, invalidOptionsMsg);
 
-// Argument types for combinatorics
+// Argument types for combinatorics.
 const a = [];
 const o = {};
 function c() {}
@@ -92,7 +92,7 @@ spawn(cmd, a);
 spawn(cmd, a, o);
 spawn(cmd, o);
 
-// Variants of undefined as explicit 'no argument' at a position
+// Variants of undefined as explicit 'no argument' at a position.
 spawn(cmd, u, o);
 spawn(cmd, a, u);
 
@@ -103,7 +103,7 @@ assert.throws(function() { spawn(cmd, s); }, TypeError);
 assert.throws(function() { spawn(cmd, a, s); }, TypeError);
 
 
-// verify that execFile has same argument parsing behavior as spawn
+// Verify that execFile has same argument parsing behavior as spawn.
 //
 // function execFile(file=f [,args=a] [, options=o] [, callback=c]) has valid
 // combinations:
@@ -124,7 +124,7 @@ execFile(cmd, o);
 execFile(cmd, o, c);
 execFile(cmd, c);
 
-// Variants of undefined as explicit 'no argument' at a position
+// Variants of undefined as explicit 'no argument' at a position.
 execFile(cmd, u, o, c);
 execFile(cmd, a, u, c);
 execFile(cmd, a, o, u);
@@ -146,7 +146,7 @@ execFile(cmd, o, n);
 execFile(cmd, c, u);
 execFile(cmd, c, n);
 
-// string is invalid in arg position (this may seem strange, but is
+// String is invalid in arg position (this may seem strange, but is
 // consistent across node API, cf. `net.createServer('not options', 'not
 // callback')`
 assert.throws(function() { execFile(cmd, s, o, c); }, TypeError);
@@ -160,10 +160,9 @@ assert.throws(function() { execFile(cmd, a, u, s); }, TypeError);
 assert.throws(function() { execFile(cmd, a, n, s); }, TypeError);
 assert.throws(function() { execFile(cmd, u, o, s); }, TypeError);
 assert.throws(function() { execFile(cmd, n, o, s); }, TypeError);
-execFile(cmd, c, s);
+execFile(cmd, c, s); // Should not throw.
 
-
-// verify that fork has same argument parsing behavior as spawn
+// Verify that fork has same argument parsing behavior as spawn.
 //
 // function fork(file=f [,args=a] [, options=o]) has valid combinations:
 //   (f)
diff --git a/test/parallel/test-console-async-write-error.js b/test/parallel/test-console-async-write-error.js
index 139c02d64bff4b..be76c89832f611 100644
--- a/test/parallel/test-console-async-write-error.js
+++ b/test/parallel/test-console-async-write-error.js
@@ -11,6 +11,5 @@ for (const method of ['dir', 'log', 'warn']) {
   });
 
   const c = new Console(out, out, true);
-
-  c[method]('abc');
+  c[method]('abc'); // Should not throw.
 }
diff --git a/test/parallel/test-console-instance.js b/test/parallel/test-console-instance.js
index aa35afc648a432..2fd07ac41219a9 100644
--- a/test/parallel/test-console-instance.js
+++ b/test/parallel/test-console-instance.js
@@ -28,15 +28,15 @@ const Console = require('console').Console;
 const out = new Stream();
 const err = new Stream();
 
-// ensure the Console instance doesn't write to the
-// process' "stdout" or "stderr" streams
+// Ensure the Console instance doesn't write to the
+// process' "stdout" or "stderr" streams.
 process.stdout.write = process.stderr.write = common.mustNotCall();
 
-// make sure that the "Console" function exists
+// Make sure that the "Console" function exists.
 assert.strictEqual('function', typeof Console);
 
-// make sure that the Console constructor throws
-// when not given a writable stream instance
+// Make sure that the Console constructor throws
+// when not given a writable stream instance.
 common.expectsError(
   () => { new Console(); },
   {
@@ -46,7 +46,7 @@ common.expectsError(
   }
 );
 
-// Console constructor should throw if stderr exists but is not writable
+// Console constructor should throw if stderr exists but is not writable.
 common.expectsError(
   () => {
     out.write = () => {};
@@ -77,7 +77,7 @@ out.write = common.mustCall((d) => {
 
 c.dir({ foo: 1 });
 
-// ensure that the console functions are bound to the console instance
+// Ensure that the console functions are bound to the console instance.
 let called = 0;
 out.write = common.mustCall((d) => {
   called++;
@@ -86,7 +86,7 @@ out.write = common.mustCall((d) => {
 
 [1, 2, 3].forEach(c.log);
 
-// Console() detects if it is called without `new` keyword
+// Console() detects if it is called without `new` keyword.
 Console(out, err);
 
 // Instance that does not ignore the stream errors.
diff --git a/test/parallel/test-console-sync-write-error.js b/test/parallel/test-console-sync-write-error.js
index 4d6c52e0dabca5..bf916ff5b84e8d 100644
--- a/test/parallel/test-console-sync-write-error.js
+++ b/test/parallel/test-console-sync-write-error.js
@@ -12,8 +12,7 @@ for (const method of ['dir', 'log', 'warn']) {
     });
 
     const c = new Console(out, out, true);
-
-    c[method]('abc');
+    c[method]('abc'); // Should not throw.
   }
 
   {
@@ -24,8 +23,7 @@ for (const method of ['dir', 'log', 'warn']) {
     });
 
     const c = new Console(out, out, true);
-
-    c[method]('abc');
+    c[method]('abc'); // Should not throw.
   }
 
   {
@@ -36,7 +34,6 @@ for (const method of ['dir', 'log', 'warn']) {
     });
 
     const c = new Console(out, out, true);
-
-    c[method]('abc');
+    c[method]('abc'); // Should not throw.
   }
 }
diff --git a/test/parallel/test-crypto-padding.js b/test/parallel/test-crypto-padding.js
index ae85f7d2c3614a..00b600efb735e8 100644
--- a/test/parallel/test-crypto-padding.js
+++ b/test/parallel/test-crypto-padding.js
@@ -29,11 +29,7 @@ const crypto = require('crypto');
 
 crypto.DEFAULT_ENCODING = 'buffer';
 
-
-/*
- * Input data
- */
-
+// Input data.
 const ODD_LENGTH_PLAIN = 'Hello node world!';
 const EVEN_LENGTH_PLAIN = 'Hello node world!AbC09876dDeFgHi';
 
@@ -42,10 +38,7 @@ const IV_PLAIN = 'blahFizz2011Buzz';
 
 const CIPHER_NAME = 'aes-128-cbc';
 
-
-/*
- * Expected result data
- */
+// Expected result data.
 
 // echo -n 'Hello node world!' | \
 // openssl enc -aes-128-cbc -e -K 5333632e722e652e742e4b2e652e5921 \
@@ -67,10 +60,7 @@ const EVEN_LENGTH_ENCRYPTED_NOPAD =
     '7f57859550d4d2fdb9806da2a750461ab46e71b3d78ebe2d9684dfc87f7575b9';
 
 
-/*
- * Helper wrappers
- */
-
+// Helper wrappers.
 function enc(plain, pad) {
   const encrypt = crypto.createCipheriv(CIPHER_NAME, KEY_PLAIN, IV_PLAIN);
   encrypt.setAutoPadding(pad);
@@ -87,16 +77,12 @@ function dec(encd, pad) {
   return plain;
 }
 
-
-/*
- * Test encryption
- */
-
+// Test encryption
 assert.strictEqual(enc(ODD_LENGTH_PLAIN, true), ODD_LENGTH_ENCRYPTED);
 assert.strictEqual(enc(EVEN_LENGTH_PLAIN, true), EVEN_LENGTH_ENCRYPTED);
 
 assert.throws(function() {
-  // input must have block length %
+  // Input must have block length %.
   enc(ODD_LENGTH_PLAIN, false);
 }, /data not multiple of block length/);
 
@@ -104,24 +90,20 @@ assert.strictEqual(
   enc(EVEN_LENGTH_PLAIN, false), EVEN_LENGTH_ENCRYPTED_NOPAD
 );
 
-
-/*
- * Test decryption
- */
-
+// Test decryption.
 assert.strictEqual(dec(ODD_LENGTH_ENCRYPTED, true), ODD_LENGTH_PLAIN);
 assert.strictEqual(dec(EVEN_LENGTH_ENCRYPTED, true), EVEN_LENGTH_PLAIN);
 
-// returns including original padding
+// Returns including original padding.
 assert.strictEqual(dec(ODD_LENGTH_ENCRYPTED, false).length, 32);
 assert.strictEqual(dec(EVEN_LENGTH_ENCRYPTED, false).length, 48);
 
 assert.throws(function() {
-  // must have at least 1 byte of padding (PKCS):
+  // Must have at least 1 byte of padding (PKCS):
   assert.strictEqual(dec(EVEN_LENGTH_ENCRYPTED_NOPAD, true), EVEN_LENGTH_PLAIN);
 }, /bad decrypt/);
 
-// no-pad encrypted string should return the same:
+// No-pad encrypted string should return the same:
 assert.strictEqual(
   dec(EVEN_LENGTH_ENCRYPTED_NOPAD, false), EVEN_LENGTH_PLAIN
 );
diff --git a/test/parallel/test-crypto-pbkdf2.js b/test/parallel/test-crypto-pbkdf2.js
index 1bb1c6cd71215e..a9a23e155ffb2f 100644
--- a/test/parallel/test-crypto-pbkdf2.js
+++ b/test/parallel/test-crypto-pbkdf2.js
@@ -99,9 +99,7 @@ common.expectsError(
 
 // Should not get FATAL ERROR with empty password and salt
 // https://github.com/nodejs/node/issues/8571
-crypto.pbkdf2('', '', 1, 32, 'sha256', common.mustCall((e) => {
-  assert.ifError(e);
-}));
+crypto.pbkdf2('', '', 1, 32, 'sha256', common.mustCall(assert.ifError));
 
 common.expectsError(
   () => crypto.pbkdf2('password', 'salt', 8, 8, common.mustNotCall()),
diff --git a/test/parallel/test-crypto-rsa-dsa.js b/test/parallel/test-crypto-rsa-dsa.js
index 5a6ecdd66f41bf..744dc5657b089d 100644
--- a/test/parallel/test-crypto-rsa-dsa.js
+++ b/test/parallel/test-crypto-rsa-dsa.js
@@ -256,7 +256,6 @@ const input = 'I AM THE WALRUS';
   // against
   const sign = crypto.createSign('SHA1');
   sign.update(input);
-
   const signOptions = { key: dsaKeyPemEncrypted, passphrase: 'password' };
   const signature = sign.sign(signOptions, 'hex');
 
diff --git a/test/parallel/test-domain-load-after-set-uncaught-exception-capture.js b/test/parallel/test-domain-load-after-set-uncaught-exception-capture.js
index c2fa523cc17019..697d4d30806ee7 100644
--- a/test/parallel/test-domain-load-after-set-uncaught-exception-capture.js
+++ b/test/parallel/test-domain-load-after-set-uncaught-exception-capture.js
@@ -13,5 +13,4 @@ common.expectsError(
 );
 
 process.setUncaughtExceptionCaptureCallback(null);
-
-require('domain');
+require('domain'); // Should not throw.
diff --git a/test/parallel/test-fs-access.js b/test/parallel/test-fs-access.js
index a55f75f649f383..9d5160f6170cad 100644
--- a/test/parallel/test-fs-access.js
+++ b/test/parallel/test-fs-access.js
@@ -105,8 +105,8 @@ common.expectsError(
     type: TypeError
   });
 
+// Regular access should not throw.
 fs.accessSync(__filename);
-
 const mode = fs.F_OK | fs.R_OK | fs.W_OK;
 fs.accessSync(readWriteFile, mode);
 
diff --git a/test/parallel/test-fs-buffer.js b/test/parallel/test-fs-buffer.js
index 0b7b67cefe4d86..f1c3484ce3a8d0 100644
--- a/test/parallel/test-fs-buffer.js
+++ b/test/parallel/test-fs-buffer.js
@@ -9,17 +9,13 @@ const path = require('path');
 const tmpdir = require('../common/tmpdir');
 tmpdir.refresh();
 
-fs.access(Buffer.from(tmpdir.path), common.mustCall((err) => {
-  assert.ifError(err);
-}));
+fs.access(Buffer.from(tmpdir.path), common.mustCall(assert.ifError));
 
 const buf = Buffer.from(path.join(tmpdir.path, 'a.txt'));
 fs.open(buf, 'w+', common.mustCall((err, fd) => {
   assert.ifError(err);
   assert(fd);
-  fs.close(fd, common.mustCall((err) => {
-    assert.ifError(err);
-  }));
+  fs.close(fd, common.mustCall(assert.ifError));
 }));
 
 assert.throws(() => {
diff --git a/test/parallel/test-fs-read-stream-throw-type-error.js b/test/parallel/test-fs-read-stream-throw-type-error.js
index b01a0a588f5699..c2b0d5452c55e3 100644
--- a/test/parallel/test-fs-read-stream-throw-type-error.js
+++ b/test/parallel/test-fs-read-stream-throw-type-error.js
@@ -4,7 +4,7 @@ const fixtures = require('../common/fixtures');
 const fs = require('fs');
 
 const example = fixtures.path('x.txt');
-
+// Should not throw.
 fs.createReadStream(example, undefined);
 fs.createReadStream(example, null);
 fs.createReadStream(example, 'utf8');
diff --git a/test/parallel/test-fs-write-stream-throw-type-error.js b/test/parallel/test-fs-write-stream-throw-type-error.js
index 553d399e238508..c80f647b3d622e 100644
--- a/test/parallel/test-fs-write-stream-throw-type-error.js
+++ b/test/parallel/test-fs-write-stream-throw-type-error.js
@@ -8,7 +8,7 @@ const tmpdir = require('../common/tmpdir');
 const example = path.join(tmpdir.path, 'dummy');
 
 tmpdir.refresh();
-
+// Should not throw.
 fs.createWriteStream(example, undefined);
 fs.createWriteStream(example, null);
 fs.createWriteStream(example, 'utf8');
diff --git a/test/parallel/test-http-invalidheaderfield.js b/test/parallel/test-http-invalidheaderfield.js
index 528fc825868ed7..01315ba69044a2 100644
--- a/test/parallel/test-http-invalidheaderfield.js
+++ b/test/parallel/test-http-invalidheaderfield.js
@@ -35,6 +35,7 @@ server.listen(0, function() {
     }
   );
 
+  // Should not throw.
   const options = {
     port: server.address().port,
     headers: { 'testing_123': 123 }
diff --git a/test/parallel/test-http2-binding.js b/test/parallel/test-http2-binding.js
index 1b8501dcbeca2f..f267e2e6c1481e 100644
--- a/test/parallel/test-http2-binding.js
+++ b/test/parallel/test-http2-binding.js
@@ -5,8 +5,6 @@ if (!common.hasCrypto)
   common.skip('missing crypto');
 const assert = require('assert');
 
-process.binding('http2');
-
 const binding = process.binding('http2');
 const http2 = require('http2');
 
diff --git a/test/parallel/test-http2-client-rststream-before-connect.js b/test/parallel/test-http2-client-rststream-before-connect.js
index 177b13a16eed98..10d7520ac125fe 100644
--- a/test/parallel/test-http2-client-rststream-before-connect.js
+++ b/test/parallel/test-http2-client-rststream-before-connect.js
@@ -19,10 +19,10 @@ server.listen(0, common.mustCall(() => {
   req.close(1);
   assert.strictEqual(req.closed, true);
 
-  // make sure that destroy is called
+  // Make sure that destroy is called.
   req._destroy = common.mustCall(req._destroy.bind(req));
 
-  // second call doesn't do anything
+  // Second call doesn't do anything.
   req.close(8);
 
   req.on('close', common.mustCall((code) => {
diff --git a/test/parallel/test-http2-compat-serverresponse-statuscode.js b/test/parallel/test-http2-compat-serverresponse-statuscode.js
index 4c51616ef618fc..dd92db8d96597a 100644
--- a/test/parallel/test-http2-compat-serverresponse-statuscode.js
+++ b/test/parallel/test-http2-compat-serverresponse-statuscode.js
@@ -27,6 +27,7 @@ server.listen(0, common.mustCall(function() {
 
     assert.strictEqual(response.statusCode, expectedDefaultStatusCode);
 
+    // Setting the response.statusCode should not throw.
     response.statusCode = realStatusCodes.ok;
     response.statusCode = realStatusCodes.multipleChoices;
     response.statusCode = realStatusCodes.badRequest;
diff --git a/test/parallel/test-http2-getpackedsettings.js b/test/parallel/test-http2-getpackedsettings.js
index b02d6b4933bbfa..56b96321139630 100644
--- a/test/parallel/test-http2-getpackedsettings.js
+++ b/test/parallel/test-http2-getpackedsettings.js
@@ -26,6 +26,7 @@ assert.deepStrictEqual(val, check);
   ['maxHeaderListSize', 0],
   ['maxHeaderListSize', 2 ** 32 - 1]
 ].forEach((i) => {
+  // Valid options should not throw.
   http2.getPackedSettings({ [i[0]]: i[1] });
 });
 
@@ -85,7 +86,7 @@ http2.getPackedSettings({ enablePush: false });
   assert.deepStrictEqual(packed, check);
 }
 
-// check for not passing settings
+// Check for not passing settings.
 {
   const packed = http2.getPackedSettings();
   assert.strictEqual(packed.length, 0);
@@ -143,7 +144,7 @@ http2.getPackedSettings({ enablePush: false });
   assert.strictEqual(settings.enablePush, true);
 }
 
-//check for what happens if passing {validate: true} and no errors happen
+// Verify that passing {validate: true} does not throw.
 {
   const packed = Buffer.from([
     0x00, 0x01, 0x00, 0x00, 0x00, 0x64, 0x00, 0x03, 0x00, 0x00,
@@ -154,7 +155,7 @@ http2.getPackedSettings({ enablePush: false });
   http2.getUnpackedSettings(packed, { validate: true });
 }
 
-// check for maxFrameSize failing the max number
+// Check for maxFrameSize failing the max number.
 {
   const packed = Buffer.from([0x00, 0x05, 0x01, 0x00, 0x00, 0x00]);
 
@@ -167,7 +168,7 @@ http2.getPackedSettings({ enablePush: false });
   });
 }
 
-// check for maxConcurrentStreams failing the max number
+// Check for maxConcurrentStreams failing the max number.
 {
   const packed = Buffer.from([0x00, 0x03, 0xFF, 0xFF, 0xFF, 0xFF]);
 
diff --git a/test/parallel/test-http2-server-startup.js b/test/parallel/test-http2-server-startup.js
index 12b9cd72cba147..4ebcc21c27aa8e 100644
--- a/test/parallel/test-http2-server-startup.js
+++ b/test/parallel/test-http2-server-startup.js
@@ -19,20 +19,20 @@ const options = {
   cert: commonFixtures.readKey('agent2-cert.pem')
 };
 
-// There should not be any throws
+// There should not be any throws.
 const serverTLS = http2.createSecureServer(options, () => {});
 serverTLS.listen(0, common.mustCall(() => serverTLS.close()));
 
-// There should not be an error event reported either
+// There should not be an error event reported either.
 serverTLS.on('error', common.mustNotCall());
 
 const server = http2.createServer(options, common.mustNotCall());
 server.listen(0, common.mustCall(() => server.close()));
 
-// There should not be an error event reported either
+// There should not be an error event reported either.
 server.on('error', common.mustNotCall());
 
-// Test the plaintext server socket timeout
+// Test the plaintext server socket timeout.
 {
   let client;
   const server = http2.createServer();
@@ -48,7 +48,7 @@ server.on('error', common.mustNotCall());
   }));
 }
 
-// Test the secure server socket timeout
+// Test the secure server socket timeout.
 {
   let client;
   const server = http2.createSecureServer(options);
diff --git a/test/parallel/test-http2-socket-proxy.js b/test/parallel/test-http2-socket-proxy.js
index e954439d78c07c..912ec673ba79cc 100644
--- a/test/parallel/test-http2-socket-proxy.js
+++ b/test/parallel/test-http2-socket-proxy.js
@@ -47,6 +47,7 @@ server.on('stream', common.mustCall(function(stream, headers) {
   common.expectsError(() => (socket.resume = undefined), errMsg);
   common.expectsError(() => (socket.write = undefined), errMsg);
 
+  // Resetting the socket listeners to their own value should not throw.
   socket.on = socket.on;
   socket.once = socket.once;
 
diff --git a/test/parallel/test-http2-withflag.js b/test/parallel/test-http2-withflag.js
deleted file mode 100644
index 3cc5c69c681c50..00000000000000
--- a/test/parallel/test-http2-withflag.js
+++ /dev/null
@@ -1,7 +0,0 @@
-'use strict';
-
-const common = require('../common');
-if (!common.hasCrypto)
-  common.skip('missing crypto');
-
-require('http2');
diff --git a/test/parallel/test-https-agent-constructor.js b/test/parallel/test-https-agent-constructor.js
index 571160bbb845dd..69156ba0f64de9 100644
--- a/test/parallel/test-https-agent-constructor.js
+++ b/test/parallel/test-https-agent-constructor.js
@@ -6,5 +6,4 @@ if (!common.hasCrypto)
 const assert = require('assert');
 const https = require('https');
 
-https.Agent();
 assert.ok(https.Agent() instanceof https.Agent);
diff --git a/test/parallel/test-icu-punycode.js b/test/parallel/test-icu-punycode.js
index 3ca30a6d168ba9..82c15287982631 100644
--- a/test/parallel/test-icu-punycode.js
+++ b/test/parallel/test-icu-punycode.js
@@ -34,12 +34,12 @@ const wptToASCIITests = require('../fixtures/url-toascii.js');
     if (output === null) {
       assert.throws(() => icu.toASCII(input),
                     errMessage, `ToASCII ${caseComment}`);
-      icu.toASCII(input, true);
+      icu.toASCII(input, true); // Should not throw.
     } else {
       assert.strictEqual(icu.toASCII(input), output, `ToASCII ${caseComment}`);
       assert.strictEqual(icu.toASCII(input, true), output,
                          `ToASCII ${caseComment} in lenient mode`);
     }
-    icu.toUnicode(input);
+    icu.toUnicode(input); // Should not throw.
   }
 }
diff --git a/test/parallel/test-internal-fs.js b/test/parallel/test-internal-fs.js
index 3f270f93d5359b..9bc0a98b099f75 100644
--- a/test/parallel/test-internal-fs.js
+++ b/test/parallel/test-internal-fs.js
@@ -4,8 +4,10 @@
 const common = require('../common');
 const fs = require('internal/fs');
 
+// Valid encodings and no args should not throw.
 fs.assertEncoding();
 fs.assertEncoding('utf8');
+
 common.expectsError(
   () => fs.assertEncoding('foo'),
   { code: 'ERR_INVALID_OPT_VALUE_ENCODING', type: TypeError }
diff --git a/test/parallel/test-internal-util-decorate-error-stack.js b/test/parallel/test-internal-util-decorate-error-stack.js
index 155a2718f90c55..5694d746c667f4 100644
--- a/test/parallel/test-internal-util-decorate-error-stack.js
+++ b/test/parallel/test-internal-util-decorate-error-stack.js
@@ -12,12 +12,13 @@ const kDecoratedPrivateSymbolIndex = binding.decorated_private_symbol;
 
 const decorateErrorStack = internalUtil.decorateErrorStack;
 
+// Verify that decorateErrorStack does not throw with non-objects.
 decorateErrorStack();
 decorateErrorStack(null);
 decorateErrorStack(1);
 decorateErrorStack(true);
 
-// Verify that a stack property is not added to non-Errors
+// Verify that a stack property is not added to non-Errors.
 const obj = {};
 decorateErrorStack(obj);
 assert.strictEqual(obj.stack, undefined);
@@ -46,12 +47,12 @@ try {
 assert(typeof err, 'object');
 checkStack(err.stack);
 
-// Verify that the stack is only decorated once
+// Verify that the stack is only decorated once.
 decorateErrorStack(err);
 decorateErrorStack(err);
 checkStack(err.stack);
 
-// Verify that the stack is only decorated once for uncaught exceptions
+// Verify that the stack is only decorated once for uncaught exceptions.
 const args = [
   '-e',
   `require('${badSyntaxPath}')`
@@ -59,14 +60,14 @@ const args = [
 const result = spawnSync(process.argv[0], args, { encoding: 'utf8' });
 checkStack(result.stderr);
 
-// Verify that the stack is unchanged when there is no arrow message
+// Verify that the stack is unchanged when there is no arrow message.
 err = new Error('foo');
 let originalStack = err.stack;
 decorateErrorStack(err);
 assert.strictEqual(originalStack, err.stack);
 
 // Verify that the arrow message is added to the start of the stack when it
-// exists
+// exists.
 const arrowMessage = 'arrow_message';
 err = new Error('foo');
 originalStack = err.stack;
diff --git a/test/parallel/test-module-symlinked-peer-modules.js b/test/parallel/test-module-symlinked-peer-modules.js
index 09ba4b17b55f3b..fb02a8a94d5d66 100644
--- a/test/parallel/test-module-symlinked-peer-modules.js
+++ b/test/parallel/test-module-symlinked-peer-modules.js
@@ -59,4 +59,4 @@ fs.writeFileSync(path.join(moduleB, 'package.json'),
 fs.writeFileSync(path.join(moduleB, 'index.js'),
                  'module.exports = 1;', 'utf8');
 
-require(path.join(app, 'index'));
+require(path.join(app, 'index')); // Should not throw.
diff --git a/test/parallel/test-net-after-close.js b/test/parallel/test-net-after-close.js
index 23e265c09a954a..0750ba0f435512 100644
--- a/test/parallel/test-net-after-close.js
+++ b/test/parallel/test-net-after-close.js
@@ -34,6 +34,8 @@ server.listen(0, common.mustCall(function() {
   c.on('close', common.mustCall(function() {
     console.error('connection closed');
     assert.strictEqual(c._handle, null);
+    // Calling functions / accessing properties of a closed socket should not
+    // throw.
     c.setNoDelay();
     c.setKeepAlive();
     c.bufferSize;
diff --git a/test/parallel/test-net-during-close.js b/test/parallel/test-net-during-close.js
index 11c3dab00f2ec6..7bceb64041f2cc 100644
--- a/test/parallel/test-net-during-close.js
+++ b/test/parallel/test-net-during-close.js
@@ -30,11 +30,11 @@ const server = net.createServer(function(socket) {
 server.listen(0, common.mustCall(function() {
   const client = net.createConnection(this.address().port);
   server.close();
-  // server connection event has not yet fired
-  // client is still attempting to connect
+  // Server connection event has not yet fired client is still attempting to
+  // connect. Accessing properties should not throw in this case.
   client.remoteAddress;
   client.remoteFamily;
   client.remotePort;
-  // exit now, do not wait for the client error event
+  // Exit now, do not wait for the client error event.
   process.exit(0);
 }));
diff --git a/test/parallel/test-process-geteuid-getegid.js b/test/parallel/test-process-geteuid-getegid.js
index 96e8765eb99015..41e37874a41b59 100644
--- a/test/parallel/test-process-geteuid-getegid.js
+++ b/test/parallel/test-process-geteuid-getegid.js
@@ -21,6 +21,7 @@ assert.throws(() => {
 
 // If we're not running as super user...
 if (process.getuid() !== 0) {
+  // Should not throw.
   process.getegid();
   process.geteuid();
 
diff --git a/test/parallel/test-process-setuid-setgid.js b/test/parallel/test-process-setuid-setgid.js
index 0060e3b1ca4af4..41fef8c9c819fa 100644
--- a/test/parallel/test-process-setuid-setgid.js
+++ b/test/parallel/test-process-setuid-setgid.js
@@ -39,6 +39,7 @@ assert.throws(() => {
 
 // If we're not running as super user...
 if (process.getuid() !== 0) {
+  // Should not throw.
   process.getgid();
   process.getuid();
 
diff --git a/test/parallel/test-querystring.js b/test/parallel/test-querystring.js
index b0ed9c4ea1d30c..2090d76b75ee34 100644
--- a/test/parallel/test-querystring.js
+++ b/test/parallel/test-querystring.js
@@ -300,7 +300,7 @@ assert.strictEqual('foo=', qs.stringify({ foo: Infinity }));
   assert.strictEqual(f, 'a=b&q=x%3Dy%26y%3Dz');
 }
 
-qs.parse(undefined);
+qs.parse(undefined); // Should not throw.
 
 // nested in colon
 {
diff --git a/test/parallel/test-readline-csi.js b/test/parallel/test-readline-csi.js
index 54ca6bde97bbe9..f5c2d3044c5cdf 100644
--- a/test/parallel/test-readline-csi.js
+++ b/test/parallel/test-readline-csi.js
@@ -61,6 +61,7 @@ assert.deepStrictEqual(writable.data, CSI.kClearLine);
   assert.deepStrictEqual(writable.data, set[2]);
 });
 
+// Undefined or null as stream should not throw.
 readline.cursorTo(null);
 readline.cursorTo();
 
diff --git a/test/parallel/test-stream-writable-null.js b/test/parallel/test-stream-writable-null.js
index 706141821be175..63e122a3b496e1 100644
--- a/test/parallel/test-stream-writable-null.js
+++ b/test/parallel/test-stream-writable-null.js
@@ -27,13 +27,9 @@ common.expectsError(
   }
 );
 
-{
-  const m = new MyWritable({ objectMode: true }).on('error', (e) => {
-    assert.ok(e);
-  });
-  m.write(null, (err) => {
-    assert.ok(err);
-  });
+{ // Should not throw.
+  const m = new MyWritable({ objectMode: true }).on('error', assert);
+  m.write(null, assert);
 }
 
 common.expectsError(
@@ -47,25 +43,19 @@ common.expectsError(
   }
 );
 
-{
-  const m = new MyWritable().on('error', (e) => {
-    assert.ok(e);
-  });
-  m.write(false, (err) => {
-    assert.ok(err);
-  });
+{ // Should not throw.
+  const m = new MyWritable().on('error', assert);
+  m.write(false, assert);
 }
 
-{
+{ // Should not throw.
   const m = new MyWritable({ objectMode: true });
-  m.write(false, (err) => assert.ifError(err));
+  m.write(false, assert.ifError);
 }
 
-{
+{ // Should not throw.
   const m = new MyWritable({ objectMode: true }).on('error', (e) => {
     assert.ifError(e || new Error('should not get here'));
   });
-  m.write(false, (err) => {
-    assert.ifError(err);
-  });
+  m.write(false, assert.ifError);
 }
diff --git a/test/parallel/test-timers-unref.js b/test/parallel/test-timers-unref.js
index d8624d8d9c9099..8c4891f1ed6459 100644
--- a/test/parallel/test-timers-unref.js
+++ b/test/parallel/test-timers-unref.js
@@ -30,6 +30,7 @@ let checks = 0;
 const LONG_TIME = 10 * 1000;
 const SHORT_TIME = 100;
 
+// Should not throw.
 setTimeout(() => {}, 10).unref().ref().unref();
 setInterval(() => {}, 10).unref().ref().unref();
 
diff --git a/test/parallel/test-util-inspect.js b/test/parallel/test-util-inspect.js
index 9133887a7570a7..ec9afc677b67bc 100644
--- a/test/parallel/test-util-inspect.js
+++ b/test/parallel/test-util-inspect.js
@@ -146,7 +146,7 @@ for (const showHidden of [true, false]) {
                      '  y: 1337 }');
 }
 
-// Now do the same checks but from a different context
+// Now do the same checks but from a different context.
 for (const showHidden of [true, false]) {
   const ab = vm.runInNewContext('new ArrayBuffer(4)');
   const dv = vm.runInNewContext('new DataView(ab, 1, 2)', { ab });
@@ -211,7 +211,7 @@ for (const showHidden of [true, false]) {
   );
 });
 
-// Now check that declaring a TypedArray in a different context works the same
+// Now check that declaring a TypedArray in a different context works the same.
 [ Float32Array,
   Float64Array,
   Int16Array,
@@ -252,7 +252,7 @@ assert.strictEqual(
   }), { showHidden: true }),
   '{ visible: 1, [hidden]: 2 }'
 );
-// Objects without prototype
+// Objects without prototype.
 assert.strictEqual(
   util.inspect(Object.create(null, {
     name: { value: 'Tim', enumerable: true },
@@ -269,7 +269,7 @@ assert.strictEqual(
   '{ name: \'Tim\' }'
 );
 
-// Dynamic properties
+// Dynamic properties.
 {
   assert.strictEqual(
     util.inspect({ get readonly() {} }),
@@ -288,7 +288,7 @@ assert.strictEqual(
   assert.strictEqual(util.inspect(value), '{ a: [Circular] }');
 }
 
-// Array with dynamic properties
+// Array with dynamic properties.
 {
   const value = [1, 2, 3];
   Object.defineProperty(
@@ -311,7 +311,7 @@ assert.strictEqual(
                      '[ 1, 2, 3, growingLength: [Getter], \'-1\': -1 ]');
 }
 
-// Array with inherited number properties
+// Array with inherited number properties.
 {
   class CustomArray extends Array {}
   CustomArray.prototype[5] = 'foo';
@@ -319,7 +319,7 @@ assert.strictEqual(
   assert.strictEqual(util.inspect(arr), 'CustomArray [ <50 empty items> ]');
 }
 
-// Array with extra properties
+// Array with extra properties.
 {
   const arr = [1, 2, 3, , ];
   arr.foo = 'bar';
@@ -351,10 +351,10 @@ assert.strictEqual(
   assert.strictEqual(util.inspect(arr3), "[ '-1': -1 ]");
 }
 
-// Indices out of bounds
+// Indices out of bounds.
 {
   const arr = [];
-  arr[2 ** 32] = true; // not a valid array index
+  arr[2 ** 32] = true; // Not a valid array index.
   assert.strictEqual(util.inspect(arr), "[ '4294967296': true ]");
   arr[0] = true;
   arr[10] = true;
@@ -374,28 +374,28 @@ assert.strictEqual(
                      ].join('\n  '));
 }
 
-// Function with properties
+// Function with properties.
 {
   const value = () => {};
   value.aprop = 42;
   assert.strictEqual(util.inspect(value), '{ [Function: value] aprop: 42 }');
 }
 
-// Anonymous function with properties
+// Anonymous function with properties.
 {
   const value = (() => function() {})();
   value.aprop = 42;
   assert.strictEqual(util.inspect(value), '{ [Function] aprop: 42 }');
 }
 
-// Regular expressions with properties
+// Regular expressions with properties.
 {
   const value = /123/ig;
   value.aprop = 42;
   assert.strictEqual(util.inspect(value), '{ /123/gi aprop: 42 }');
 }
 
-// Dates with properties
+// Dates with properties.
 {
   const value = new Date('Sun, 14 Feb 2010 11:48:40 GMT');
   value.aprop = 42;
@@ -403,7 +403,7 @@ assert.strictEqual(
                      '{ 2010-02-14T11:48:40.000Z aprop: 42 }');
 }
 
-// test the internal isDate implementation
+// Test the internal isDate implementation.
 {
   const Date2 = vm.runInNewContext('Date');
   const d = new Date2();
@@ -413,13 +413,13 @@ assert.strictEqual(
   assert.strictEqual(orig, after);
 }
 
-// test positive/negative zero
+// Test positive/negative zero.
 assert.strictEqual(util.inspect(0), '0');
 assert.strictEqual(util.inspect(-0), '-0');
-// edge case from check
+// Edge case from check.
 assert.strictEqual(util.inspect(-5e-324), '-5e-324');
 
-// test for sparse array
+// Test for sparse array.
 {
   const a = ['foo', 'bar', 'baz'];
   assert.strictEqual(util.inspect(a), '[ \'foo\', \'bar\', \'baz\' ]');
@@ -443,7 +443,7 @@ assert.strictEqual(util.inspect(-5e-324), '-5e-324');
   );
 }
 
-// test for Array constructor in different context
+// Test for Array constructor in different context.
 {
   const Debug = vm.runInDebugContext('Debug');
   const map = new Map();
@@ -458,7 +458,7 @@ assert.strictEqual(util.inspect(-5e-324), '-5e-324');
   assert.strictEqual(util.inspect(valsOutput), '[ [ 1, 2 ] ]');
 }
 
-// test for other constructors in different context
+// Test for other constructors in different context.
 {
   let obj = vm.runInNewContext('(function(){return {}})()', {});
   assert.strictEqual(util.inspect(obj), '{}');
@@ -470,7 +470,7 @@ assert.strictEqual(util.inspect(-5e-324), '-5e-324');
   assert.strictEqual(util.inspect(obj), 'Promise { <pending> }');
 }
 
-// test for property descriptors
+// Test for property descriptors.
 {
   const getter = Object.create(null, {
     a: {
@@ -496,7 +496,7 @@ assert.strictEqual(util.inspect(-5e-324), '-5e-324');
   );
 }
 
-// exceptions should print the error message, not '{}'
+// Exceptions should print the error message, not '{}'.
 {
   const errors = [];
   errors.push(new Error());
@@ -517,7 +517,7 @@ assert.strictEqual(util.inspect(-5e-324), '-5e-324');
   assert(ex.includes('[message]'));
 }
 
-// Doesn't capture stack trace
+// Doesn't capture stack trace.
 {
   function BadCustomError(msg) {
     Error.call(this);
@@ -534,7 +534,6 @@ assert.strictEqual(util.inspect(-5e-324), '-5e-324');
 }
 
 // GH-1941
-// should not throw:
 assert.strictEqual(util.inspect(Object.create(Date.prototype)), 'Date {}');
 
 // GH-1944
@@ -544,20 +543,20 @@ assert.strictEqual(util.inspect(Object.create(Date.prototype)), 'Date {}');
   util.inspect(d);
 }
 
+// Should not throw.
 {
   const d = new Date();
   d.toISOString = null;
   util.inspect(d);
 }
 
+// Should not throw.
 const r = /regexp/;
 r.toString = null;
 util.inspect(r);
 
-// bug with user-supplied inspect function returns non-string
-util.inspect([{
-  inspect: () => 123
-}]);
+// Bug with user-supplied inspect function returns non-string.
+util.inspect([{ inspect: () => 123 }]);
 
 // GH-2225
 {
@@ -593,7 +592,7 @@ util.inspect([{
   );
 }
 
-// util.inspect.styles and util.inspect.colors
+// Test util.inspect.styles and util.inspect.colors.
 {
   function testColorStyle(style, input, implicit) {
     const colorName = util.inspect.styles[style];
@@ -620,12 +619,10 @@ util.inspect([{
   testColorStyle('regexp', /regexp/);
 }
 
-// an object with "hasOwnProperty" overwritten should not throw
-util.inspect({
-  hasOwnProperty: null
-});
+// An object with "hasOwnProperty" overwritten should not throw.
+util.inspect({ hasOwnProperty: null });
 
-// new API, accepts an "options" object
+// New API, accepts an "options" object.
 {
   const subject = { foo: 'bar', hello: 31, a: { b: { c: { d: 0 } } } };
   Object.defineProperty(subject, 'hidden', { enumerable: false, value: null });
@@ -665,7 +662,7 @@ util.inspect({
 }
 
 {
-  // "customInspect" option can enable/disable calling inspect() on objects
+  // "customInspect" option can enable/disable calling inspect() on objects.
   const subject = { inspect: () => 123 };
 
   assert.strictEqual(
@@ -685,7 +682,7 @@ util.inspect({
     true
   );
 
-  // custom inspect() functions should be able to return other Objects
+  // Custom inspect() functions should be able to return other Objects.
   subject.inspect = () => ({ foo: 'bar' });
 
   assert.strictEqual(util.inspect(subject), '{ foo: \'bar\' }');
@@ -698,7 +695,7 @@ util.inspect({
 }
 
 {
-  // "customInspect" option can enable/disable calling [util.inspect.custom]()
+  // "customInspect" option can enable/disable calling [util.inspect.custom]().
   const subject = { [util.inspect.custom]: () => 123 };
 
   assert.strictEqual(
@@ -710,7 +707,7 @@ util.inspect({
     false
   );
 
-  // a custom [util.inspect.custom]() should be able to return other Objects
+  // A custom [util.inspect.custom]() should be able to return other Objects.
   subject[util.inspect.custom] = () => ({ foo: 'bar' });
 
   assert.strictEqual(util.inspect(subject), '{ foo: \'bar\' }');
@@ -723,7 +720,7 @@ util.inspect({
 }
 
 {
-  // [util.inspect.custom] takes precedence over inspect
+  // [util.inspect.custom] takes precedence over inspect.
   const subject = {
     [util.inspect.custom]() { return 123; },
     inspect() { return 456; }
@@ -758,7 +755,7 @@ util.inspect({
                      `{ a: 123,\n  [Symbol(${UIC})]: [Function: [${UIC}]] }`);
 }
 
-// util.inspect with "colors" option should produce as many lines as without it
+// util.inspect with "colors" option should produce as many lines as without it.
 {
   function testLines(input) {
     const countLines = (str) => (str.match(/\n/g) || []).length;
@@ -782,7 +779,7 @@ util.inspect({
   });
 }
 
-// test boxed primitives output the correct values
+// Test boxed primitives output the correct values.
 assert.strictEqual(util.inspect(new String('test')), '[String: \'test\']');
 assert.strictEqual(
   util.inspect(Object(Symbol('test'))),
@@ -795,7 +792,7 @@ assert.strictEqual(util.inspect(new Number(-0)), '[Number: -0]');
 assert.strictEqual(util.inspect(new Number(-1.1)), '[Number: -1.1]');
 assert.strictEqual(util.inspect(new Number(13.37)), '[Number: 13.37]');
 
-// test boxed primitives with own properties
+// Test boxed primitives with own properties.
 {
   const str = new String('baz');
   str.foo = 'bar';
@@ -810,7 +807,7 @@ assert.strictEqual(util.inspect(new Number(13.37)), '[Number: 13.37]');
   assert.strictEqual(util.inspect(num), '{ [Number: 13.37] foo: \'bar\' }');
 }
 
-// test es6 Symbol
+// Test es6 Symbol.
 if (typeof Symbol !== 'undefined') {
   assert.strictEqual(util.inspect(Symbol()), 'Symbol()');
   assert.strictEqual(util.inspect(Symbol(123)), 'Symbol(123)');
@@ -846,7 +843,7 @@ if (typeof Symbol !== 'undefined') {
                      '[ 1, 2, 3, [Symbol(symbol)]: 42 ]');
 }
 
-// test Set
+// Test Set.
 {
   assert.strictEqual(util.inspect(new Set()), 'Set {}');
   assert.strictEqual(util.inspect(new Set([1, 2, 3])), 'Set { 1, 2, 3 }');
@@ -858,14 +855,14 @@ if (typeof Symbol !== 'undefined') {
   );
 }
 
-// Test circular Set
+// Test circular Set.
 {
   const set = new Set();
   set.add(set);
   assert.strictEqual(util.inspect(set), 'Set { [Circular] }');
 }
 
-// test Map
+// Test Map.
 {
   assert.strictEqual(util.inspect(new Map()), 'Map {}');
   assert.strictEqual(util.inspect(new Map([[1, 'a'], [2, 'b'], [3, 'c']])),
@@ -876,7 +873,7 @@ if (typeof Symbol !== 'undefined') {
                      'Map { \'foo\' => null, [size]: 1, bar: 42 }');
 }
 
-// Test circular Map
+// Test circular Map.
 {
   const map = new Map();
   map.set(map, 'map');
@@ -888,14 +885,14 @@ if (typeof Symbol !== 'undefined') {
   assert.strictEqual(util.inspect(map), "Map { 'map' => [Circular] }");
 }
 
-// test Promise
+// Test Promise.
 {
   const resolved = Promise.resolve(3);
   assert.strictEqual(util.inspect(resolved), 'Promise { 3 }');
 
   const rejected = Promise.reject(3);
   assert.strictEqual(util.inspect(rejected), 'Promise { <rejected> 3 }');
-  // squelch UnhandledPromiseRejection
+  // Squelch UnhandledPromiseRejection.
   rejected.catch(() => {});
 
   const pending = new Promise(() => {});
@@ -917,33 +914,33 @@ if (typeof Symbol !== 'undefined') {
   global.Promise = oldPromise;
 }
 
-// Test Map iterators
+// Test Map iterators.
 {
   const map = new Map([['foo', 'bar']]);
   assert.strictEqual(util.inspect(map.keys()), 'MapIterator { \'foo\' }');
   assert.strictEqual(util.inspect(map.values()), 'MapIterator { \'bar\' }');
   assert.strictEqual(util.inspect(map.entries()),
                      'MapIterator { [ \'foo\', \'bar\' ] }');
-  // make sure the iterator doesn't get consumed
+  // Make sure the iterator doesn't get consumed.
   const keys = map.keys();
   assert.strictEqual(util.inspect(keys), 'MapIterator { \'foo\' }');
   assert.strictEqual(util.inspect(keys), 'MapIterator { \'foo\' }');
 }
 
-// Test Set iterators
+// Test Set iterators.
 {
   const aSet = new Set([1, 3]);
   assert.strictEqual(util.inspect(aSet.keys()), 'SetIterator { 1, 3 }');
   assert.strictEqual(util.inspect(aSet.values()), 'SetIterator { 1, 3 }');
   assert.strictEqual(util.inspect(aSet.entries()),
                      'SetIterator { [ 1, 1 ], [ 3, 3 ] }');
-  // make sure the iterator doesn't get consumed
+  // Make sure the iterator doesn't get consumed.
   const keys = aSet.keys();
   assert.strictEqual(util.inspect(keys), 'SetIterator { 1, 3 }');
   assert.strictEqual(util.inspect(keys), 'SetIterator { 1, 3 }');
 }
 
-// Test alignment of items in container
+// Test alignment of items in container.
 // Assumes that the first numeric character is the start of an item.
 {
   function checkAlignment(container) {
@@ -978,7 +975,7 @@ if (typeof Symbol !== 'undefined') {
 }
 
 
-// Test display of constructors
+// Test display of constructors.
 {
   class ObjectSubclass {}
   class ArraySubclass extends Array {}
@@ -1004,7 +1001,7 @@ if (typeof Symbol !== 'undefined') {
   );
 }
 
-// Empty and circular before depth
+// Empty and circular before depth.
 {
   const arr = [[[[]]]];
   assert.strictEqual(util.inspect(arr), '[ [ [ [] ] ] ]');
@@ -1100,14 +1097,14 @@ if (typeof Symbol !== 'undefined') {
   assert.strictEqual(twoLines, '{ foo: \'abc\',\n  bar: \'xyz\' }');
 }
 
-// util.inspect.defaultOptions tests
+// util.inspect.defaultOptions tests.
 {
   const arr = new Array(101).fill();
   const obj = { a: { a: { a: { a: 1 } } } };
 
   const oldOptions = Object.assign({}, util.inspect.defaultOptions);
 
-  // Set single option through property assignment
+  // Set single option through property assignment.
   util.inspect.defaultOptions.maxArrayLength = null;
   assert(!/1 more item/.test(util.inspect(arr)));
   util.inspect.defaultOptions.maxArrayLength = oldOptions.maxArrayLength;
@@ -1121,7 +1118,7 @@ if (typeof Symbol !== 'undefined') {
     JSON.stringify(oldOptions)
   );
 
-  // Set multiple options through object assignment
+  // Set multiple options through object assignment.
   util.inspect.defaultOptions = { maxArrayLength: null, depth: null };
   assert(!/1 more item/.test(util.inspect(arr)));
   assert(!/Object/.test(util.inspect(obj)));
diff --git a/test/parallel/test-vm-create-context-arg.js b/test/parallel/test-vm-create-context-arg.js
index f5497153815de3..2bcdc8573fe311 100644
--- a/test/parallel/test-vm-create-context-arg.js
+++ b/test/parallel/test-vm-create-context-arg.js
@@ -28,6 +28,7 @@ assert.throws(function() {
   vm.createContext('string is not supported');
 }, /^TypeError: sandbox must be an object$/);
 
+// Should not throw.
 vm.createContext({ a: 1 });
 vm.createContext([0, 1, 2, 3]);
 
diff --git a/test/parallel/test-vm-cross-context.js b/test/parallel/test-vm-cross-context.js
index 785cc9d7bd06bb..b7cf1309d3689f 100644
--- a/test/parallel/test-vm-cross-context.js
+++ b/test/parallel/test-vm-cross-context.js
@@ -25,4 +25,5 @@ require('../common');
 const vm = require('vm');
 const ctx = vm.createContext(global);
 
+// Should not throw.
 vm.runInContext('!function() { var x = console.log; }()', ctx);
diff --git a/test/pummel/test-fs-largefile.js b/test/pummel/test-fs-largefile.js
index 369f8311925474..2e9dda0495bd6e 100644
--- a/test/pummel/test-fs-largefile.js
+++ b/test/pummel/test-fs-largefile.js
@@ -44,6 +44,7 @@ assert.strictEqual(readBuf.toString(), message);
 fs.readSync(fd, readBuf, 0, 1, 0);
 assert.strictEqual(readBuf[0], 0);
 
+// Verify that floating point positions do not throw.
 fs.writeSync(fd, writeBuf, 0, writeBuf.length, 42.000001);
 fs.close(fd);
 
diff --git a/test/pummel/test-fs-watch-file.js b/test/pummel/test-fs-watch-file.js
index 62abf0c18fc969..e9d208778faf3f 100644
--- a/test/pummel/test-fs-watch-file.js
+++ b/test/pummel/test-fs-watch-file.js
@@ -68,6 +68,7 @@ assert.throws(
   }
 );
 
+// Does not throw.
 fs.watchFile(filepathOne, function() {
   fs.unwatchFile(filepathOne);
   ++watchSeenOne;
@@ -91,7 +92,7 @@ assert.throws(
   }
 );
 
-{
+{ // Does not throw.
   function a() {
     fs.unwatchFile(filepathTwo, a);
     ++watchSeenTwo;
@@ -108,7 +109,7 @@ setTimeout(function() {
   fs.writeFileSync(filepathTwoAbs, 'pardner');
 }, 1000);
 
-{
+{ // Does not throw.
   function b() {
     fs.unwatchFile(filenameThree, b);
     ++watchSeenThree;
@@ -130,7 +131,7 @@ setTimeout(function() {
   fs.writeFileSync(filenameFour, 'hey');
 }, 500);
 
-{
+{ // Does not throw.
   function a() {
     ++watchSeenFour;
     assert.strictEqual(1, watchSeenFour);
diff --git a/test/sequential/test-inspector-module.js b/test/sequential/test-inspector-module.js
index 5b793bf3b43d55..f97d71297971f7 100644
--- a/test/sequential/test-inspector-module.js
+++ b/test/sequential/test-inspector-module.js
@@ -56,4 +56,5 @@ common.expectsError(
 );
 
 session.disconnect();
+// Calling disconnect twice should not throw.
 session.disconnect();
diff --git a/test/sequential/test-performance.js b/test/sequential/test-performance.js
index 80bfe217a0518e..770ca7bf6407be 100644
--- a/test/sequential/test-performance.js
+++ b/test/sequential/test-performance.js
@@ -70,7 +70,7 @@ assert(inited < 20000);
 {
   performance.mark('A');
   [undefined, null, 'foo', 'initialize', 1].forEach((i) => {
-    performance.measure('test', i, 'A');
+    performance.measure('test', i, 'A'); // Should not throw.
   });
 
   [undefined, null, 'foo', 1].forEach((i) => {