test: add path.join's test

Add test when the argument is empty.
Adjust the position of the comment.
Make use of Arrow Function, Template Literals and `Array.from`.
PR-URL: #11063
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

Author: hiroppy

test/parallel/test-path.js

@@ -60,8 +60,8 @@ assert.strictEqual(path.posix.basename('foo'), 'foo');
 
 // POSIX filenames may include control characters
 // c.f. http://www.dwheeler.com/essays/fixing-unix-linux-filenames.html
-constcontrolCharFilename='Icon'+String.fromCharCode(13);
-assert.strictEqual(path.posix.basename('/a/b/'+controlCharFilename),
+constcontrolCharFilename=`Icon${String.fromCharCode(13)}`;
+assert.strictEqual(path.posix.basename(`/a/b/${controlCharFilename}`),
 controlCharFilename);
 
 
@@ -162,8 +162,8 @@ assert.strictEqual(path.win32.dirname('foo'), '.');
 ['file//',''],
 ['file./','.'],
 ['file.//','.'],
-].forEach(function(test){
-[path.posix.extname,path.win32.extname].forEach(function(extname){
+].forEach((test)=>{
+[path.posix.extname,path.win32.extname].forEach((extname)=>{
 letinput=test[0];
 letos;
 if(extname===path.win32.extname){
@@ -210,6 +210,7 @@ const joinTests = [
 [[path.posix.join,path.win32.join],
 // arguments result
 [[['.','x/b','..','/b/c.js'],'x/b/c.js'],
+[[],'.'],
 [['/.','x/b','..','/b/c.js'],'/x/b/c.js'],
 [['/foo','../../../bar'],'/bar'],
 [['foo','../../../bar'],'../../bar'],
@@ -312,11 +313,11 @@ joinTests.push([
 ]
 )
 ]);
-joinTests.forEach(function(test){
+joinTests.forEach((test)=>{
 if(!Array.isArray(test[0]))
 test[0]=[test[0]];
-test[0].forEach(function(join){
-test[1].forEach(function(test){
+test[0].forEach((join)=>{
+test[1].forEach((test)=>{
 constactual=join.apply(null,test[0]);
 constexpected=test[1];
 // For non-Windows specific tests with the Windows join(), we need to try
@@ -335,7 +336,7 @@ joinTests.forEach(function(test) {
 '\n expect='+JSON.stringify(expected)+
 '\n actual='+JSON.stringify(actual);
 if(actual!==expected&&actualAlt!==expected)
-failures.push('\n'+message);
+failures.push(`\n${message}`);
 });
 });
 });
@@ -346,15 +347,15 @@ assert.strictEqual(failures.length, 0, failures.join(''));
 consttypeErrorTests=[true,false,7,null,{},undefined,[],NaN];
 
 functionfail(fn){
-constargs=Array.prototype.slice.call(arguments,1);
+constargs=Array.from(arguments).slice(1);
 
-assert.throws(function(){
+assert.throws(()=>{
 fn.apply(null,args);
 },TypeError);
 }
 
-typeErrorTests.forEach(function(test){
-[path.posix,path.win32].forEach(function(namespace){
+typeErrorTests.forEach((test)=>{
+[path.posix,path.win32].forEach((namespace)=>{
 fail(namespace.join,test);
 fail(namespace.resolve,test);
 fail(namespace.normalize,test);
@@ -398,7 +399,7 @@ assert.strictEqual(path.posix.normalize('///..//./foo/.//bar'), '/foo/bar');
 // path.resolve tests
 constresolveTests=[
 [path.win32.resolve,
-// arguments result
+// arguments result
 [[['c:/blah\\blah','d:/games','c:../a'],'c:\\blah\\a'],
 [['c:/ignore','d:\\a/b\\c/d','\\e.exe'],'d:\\e.exe'],
 [['c:/ignore','c:/some/file'],'c:\\some\\file'],
@@ -415,7 +416,7 @@ const resolveTests = [
 ]
 ],
 [path.posix.resolve,
-// arguments result
+// arguments result
 [[['/var/lib','../','file/'],'/var/file'],
 [['/var/lib','/../','file/'],'/file'],
 [['a/b/c/','../../..'],process.cwd()],
@@ -425,9 +426,9 @@ const resolveTests = [
 ]
 ]
 ];
-resolveTests.forEach(function(test){
+resolveTests.forEach((test)=>{
 constresolve=test[0];
-test[1].forEach(function(test){
+test[1].forEach((test)=>{
 constactual=resolve.apply(null,test[0]);
 letactualAlt;
 constos=resolve===path.win32.resolve ? 'win32' : 'posix';
@@ -516,7 +517,7 @@ const relativeTests = [
 ]
 ],
 [path.posix.relative,
-// arguments result
+// arguments result
 [['/var/lib','/var','..'],
 ['/var/lib','/bin','../../bin'],
 ['/var/lib','/var/lib',''],
@@ -532,9 +533,9 @@ const relativeTests = [
 ]
 ]
 ];
-relativeTests.forEach(function(test){
+relativeTests.forEach((test)=>{
 constrelative=test[0];
-test[1].forEach(function(test){
+test[1].forEach((test)=>{
 constactual=relative(test[0],test[1]);
 constexpected=test[2];
 constos=relative===path.win32.relative ? 'win32' : 'posix';
@@ -545,7 +546,7 @@ relativeTests.forEach(function(test) {
 '\n expect='+JSON.stringify(expected)+
 '\n actual='+JSON.stringify(actual);
 if(actual!==expected)
-failures.push('\n'+message);
+failures.push(`\n${message}`);
 });
 });
 assert.strictEqual(failures.length,0,failures.join(''));
@@ -577,14 +578,14 @@ if (common.isWindows) {
 // These tests cause resolve() to insert the cwd, so we cannot test them from
 // non-Windows platforms (easily)
 assert.strictEqual(path.win32._makeLong('foo\\bar').toLowerCase(),
-'\\\\?\\'+process.cwd().toLowerCase()+'\\foo\\bar');
+`\\\\?\\${process.cwd().toLowerCase()}\\foo\\bar`);
 assert.strictEqual(path.win32._makeLong('foo/bar').toLowerCase(),
-'\\\\?\\'+process.cwd().toLowerCase()+'\\foo\\bar');
+`\\\\?\\${process.cwd().toLowerCase()}\\foo\\bar`);
 constcurrentDeviceLetter=path.parse(process.cwd()).root.substring(0,2);
 assert.strictEqual(path.win32._makeLong(currentDeviceLetter).toLowerCase(),
-'\\\\?\\'+process.cwd().toLowerCase());
+`\\\\?\\${process.cwd().toLowerCase()}`);
 assert.strictEqual(path.win32._makeLong('C').toLowerCase(),
-'\\\\?\\'+process.cwd().toLowerCase()+'\\c');
+`\\\\?\\${process.cwd().toLowerCase()}\\c`);
 }
 assert.strictEqual(path.win32._makeLong('C:\\foo'),'\\\\?\\C:\\foo');
 assert.strictEqual(path.win32._makeLong('C:/foo'),'\\\\?\\C:\\foo');