test: add comment describing test-fs-mkdir

PR-URL: #22424 Reviewed-By: Richard Lau <[email protected]> Reviewed-By: Rich Trott <[email protected]> Reviewed-By: Gireesh Punathil <[email protected]> Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ruben Bridgewater <[email protected]> Reviewed-By: Trivikram Kamat <[email protected]> Reviewed-By: Ben Coe <[email protected]> Reviewed-By: Tiancheng "Timothy" Gu <[email protected]>

Author: Jennifer Bland

test/parallel/test-fs-mkdir.js

@@ -33,6 +33,7 @@ function nextdir(){
 return`test${++dirc}`;
 }
 
+// mkdir creates directory using assigned path
 {
 constpathname=path.join(tmpdir.path,nextdir());
 
@@ -42,6 +43,7 @@ function nextdir(){
 }));
 }
 
+// mkdir creates directory with assigned mode value
 {
 constpathname=path.join(tmpdir.path,nextdir());
 
@@ -51,6 +53,7 @@ function nextdir(){
 }));
 }
 
+// mkdirSync successfully creates directory from given path
 {
 constpathname=path.join(tmpdir.path,nextdir());
 
@@ -60,6 +63,8 @@ function nextdir(){
 assert.strictEqual(exists,true);
 }
 
+// mkdirSync and mkdir require path to be a string, buffer or url.
+// Anything else generates an error.
 [false,1,{},[],null,undefined].forEach((i)=>{
 common.expectsError(
 ()=>fs.mkdir(i,common.mustNotCall()),