diff --git a/test/parallel/test-buffer-negative-length.js b/test/parallel/test-buffer-negative-length.js
deleted file mode 100644
index bf903b933d2689..00000000000000
--- a/test/parallel/test-buffer-negative-length.js
+++ /dev/null
@@ -1,17 +0,0 @@
-'use strict';
-
-const common = require('../common');
-const assert = require('assert');
-const SlowBuffer = require('buffer').SlowBuffer;
-
-const bufferNegativeMsg = common.expectsError({
-  code: 'ERR_INVALID_OPT_VALUE',
-  type: RangeError,
-  message: /^The value "[^"]*" is invalid for option "size"$/
-}, 5);
-assert.throws(() => Buffer(-1).toString('utf8'), bufferNegativeMsg);
-assert.throws(() => SlowBuffer(-1).toString('utf8'), bufferNegativeMsg);
-assert.throws(() => Buffer.alloc(-1).toString('utf8'), bufferNegativeMsg);
-assert.throws(() => Buffer.allocUnsafe(-1).toString('utf8'), bufferNegativeMsg);
-assert.throws(() => Buffer.allocUnsafeSlow(-1).toString('utf8'),
-              bufferNegativeMsg);
diff --git a/test/parallel/test-buffer-no-negative-allocation.js b/test/parallel/test-buffer-no-negative-allocation.js
index b34477aa8c4b45..6d44e432f3c780 100644
--- a/test/parallel/test-buffer-no-negative-allocation.js
+++ b/test/parallel/test-buffer-no-negative-allocation.js
@@ -2,12 +2,13 @@
 
 const common = require('../common');
 const assert = require('assert');
+const { SlowBuffer } = require('buffer');
 
 const msg = common.expectsError({
   code: 'ERR_INVALID_OPT_VALUE',
   type: RangeError,
   message: /^The value "[^"]*" is invalid for option "size"$/
-}, 12);
+}, 15);
 
 // Test that negative Buffer length inputs throw errors.
 
@@ -26,3 +27,7 @@ assert.throws(() => Buffer.allocUnsafe(-1), msg);
 assert.throws(() => Buffer.allocUnsafeSlow(-Buffer.poolSize), msg);
 assert.throws(() => Buffer.allocUnsafeSlow(-100), msg);
 assert.throws(() => Buffer.allocUnsafeSlow(-1), msg);
+
+assert.throws(() => SlowBuffer(-Buffer.poolSize), msg);
+assert.throws(() => SlowBuffer(-100), msg);
+assert.throws(() => SlowBuffer(-1), msg);