diff --git a/test/parallel/test-fs-read-file-assert-encoding.js b/test/parallel/test-fs-read-file-assert-encoding.js
index 929caf88bd4748..ac0f45f98b30d4 100644
--- a/test/parallel/test-fs-read-file-assert-encoding.js
+++ b/test/parallel/test-fs-read-file-assert-encoding.js
@@ -8,6 +8,6 @@ const encoding = 'foo-8';
 const filename = 'bar.txt';
 
 assert.throws(
-  fs.readFile.bind(fs, filename, { encoding }, common.noop),
-  new RegExp(`Error: Unknown encoding: ${encoding}$`)
+  fs.readFile.bind(fs, filename, { encoding }, common.mustNotCall()),
+  new RegExp(`^Error: Unknown encoding: ${encoding}$`)
 );
diff --git a/test/parallel/test-fs-read-type.js b/test/parallel/test-fs-read-type.js
index e62405c48eef81..c6e3e53f054a63 100644
--- a/test/parallel/test-fs-read-type.js
+++ b/test/parallel/test-fs-read-type.js
@@ -13,9 +13,9 @@ assert.throws(() => {
           expected.length,
           0,
           'utf-8',
-          common.noop);
-}, /Second argument needs to be a buffer/);
+          common.mustNotCall());
+}, /^TypeError: Second argument needs to be a buffer$/);
 
 assert.throws(() => {
   fs.readSync(fd, expected.length, 0, 'utf-8');
-}, /Second argument needs to be a buffer/);
+}, /^TypeError: Second argument needs to be a buffer$/);