test: refactor test-fs-write-file-sync.js

This commit reduces shared state by introducing scopes and
block scoped variables. It also makes the monkey patching used
by the test more robust.
PR-URL: #24834
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>

Author: cjihrig

test/parallel/test-fs-write-file-sync.js

@@ -21,87 +21,83 @@
 
 'use strict';
 constcommon=require('../common');
-constassert=require('assert');
-constpath=require('path');
-constfs=require('fs');
-letopenCount=0;
-letmode;
-letcontent;
 
 if(!common.isMainThread)
 common.skip('process.umask is not available in Workers');
 
-// Need to hijack fs.open/close to make sure that things
-// get closed once they're opened.
-fs._openSync=fs.openSync;
-fs.openSync=openSync;
-fs._closeSync=fs.closeSync;
-fs.closeSync=closeSync;
-
-// Reset the umask for testing
-process.umask(0o000);
+constassert=require('assert');
+constpath=require('path');
+constfs=require('fs');
 
 // On Windows chmod is only able to manipulate read-only bit. Test if creating
 // the file in read-only mode works.
-if(common.isWindows){
-mode=0o444;
-}else{
-mode=0o755;
-}
+constmode=common.isWindows ? 0o444 : 0o755;
+
+// Reset the umask for testing
+process.umask(0o000);
 
 consttmpdir=require('../common/tmpdir');
 tmpdir.refresh();
 
 // Test writeFileSync
-constfile1=path.join(tmpdir.path,'testWriteFileSync.txt');
-
-fs.writeFileSync(file1,'123',{ mode });
+{
+constfile=path.join(tmpdir.path,'testWriteFileSync.txt');
 
-content=fs.readFileSync(file1,{encoding: 'utf8'});
-assert.strictEqual(content,'123');
-
-assert.strictEqual(fs.statSync(file1).mode&0o777,mode);
+fs.writeFileSync(file,'123',{ mode });
+constcontent=fs.readFileSync(file,{encoding: 'utf8'});
+assert.strictEqual(content,'123');
+assert.strictEqual(fs.statSync(file).mode&0o777,mode);
+}
 
 // Test appendFileSync
-constfile2=path.join(tmpdir.path,'testAppendFileSync.txt');
-
-fs.appendFileSync(file2,'abc',{ mode });
-
-content=fs.readFileSync(file2,{encoding: 'utf8'});
-assert.strictEqual(content,'abc');
-
-assert.strictEqual(fs.statSync(file2).mode&mode,mode);
-
-// Test writeFileSync with file descriptor
-constfile3=path.join(tmpdir.path,'testWriteFileSyncFd.txt');
+{
+constfile=path.join(tmpdir.path,'testAppendFileSync.txt');
 
-constfd=fs.openSync(file3,'w+',mode);
-fs.writeFileSync(fd,'123');
-fs.closeSync(fd);
-
-content=fs.readFileSync(file3,{encoding: 'utf8'});
-assert.strictEqual(content,'123');
-
-assert.strictEqual(fs.statSync(file3).mode&0o777,mode);
-
-// Verify that all opened files were closed.
-assert.strictEqual(openCount,0);
-
-functionopenSync(){
-openCount++;
-returnfs._openSync.apply(fs,arguments);
+fs.appendFileSync(file,'abc',{ mode });
+constcontent=fs.readFileSync(file,{encoding: 'utf8'});
+assert.strictEqual(content,'abc');
+assert.strictEqual(fs.statSync(file).mode&mode,mode);
 }
 
-functioncloseSync(){
-openCount--;
-returnfs._closeSync.apply(fs,arguments);
+// Test writeFileSync with file descriptor
+{
+// Need to hijack fs.open/close to make sure that things
+// get closed once they're opened.
+const_openSync=fs.openSync;
+const_closeSync=fs.closeSync;
+letopenCount=0;
+
+fs.openSync=(...args)=>{
+openCount++;
+return_openSync(...args);
+};
+
+fs.closeSync=(...args)=>{
+openCount--;
+return_closeSync(...args);
+};
+
+constfile=path.join(tmpdir.path,'testWriteFileSyncFd.txt');
+constfd=fs.openSync(file,'w+',mode);
+
+fs.writeFileSync(fd,'123');
+fs.closeSync(fd);
+constcontent=fs.readFileSync(file,{encoding: 'utf8'});
+assert.strictEqual(content,'123');
+assert.strictEqual(fs.statSync(file).mode&0o777,mode);
+
+// Verify that all opened files were closed.
+assert.strictEqual(openCount,0);
+fs.openSync=_openSync;
+fs.closeSync=_closeSync;
 }
 
 // Test writeFileSync with flags
-constfile4=path.join(tmpdir.path,'testWriteFileSyncFlags.txt');
-
-fs.writeFileSync(file4,'hello ',{encoding: 'utf8',flag: 'a'});
-fs.writeFileSync(file4,'world!',{encoding: 'utf8',flag: 'a'});
+{
+constfile=path.join(tmpdir.path,'testWriteFileSyncFlags.txt');
 
-content=fs.readFileSync(file4,{encoding: 'utf8'});
-assert.strictEqual(content,'hello world!');
+fs.writeFileSync(file,'hello ',{encoding: 'utf8',flag: 'a'});
+fs.writeFileSync(file,'world!',{encoding: 'utf8',flag: 'a'});
+constcontent=fs.readFileSync(file,{encoding: 'utf8'});
+assert.strictEqual(content,'hello world!');
+}