test: refactor test-cli-eval.js

PR-URL: #10898
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

Author: cjihrig

test/parallel/test-cli-eval.js

@@ -1,6 +1,7 @@
 'use strict';
 if(module.parent){
-// signal we've been loaded as a module
+// Signal we've been loaded as a module.
+// The following console.log() is part of the test.
 console.log('Loaded as a module, exiting with status code 42.');
 process.exit(42);
 }
@@ -9,114 +10,114 @@ const common = require('../common');
 constassert=require('assert');
 constchild=require('child_process');
 constpath=require('path');
-constnodejs='"'+process.execPath+'"';
+constnodejs=`"${process.execPath}"`;
 
+// Assert that nothing is written to stdout.
+child.exec(`${nodejs} --eval 42`,common.mustCall((err,stdout,stderr)=>{
+assert.ifError(err);
+assert.strictEqual(stdout,'');
+assert.strictEqual(stderr,'');
+}));
 
-// replace \ by / because windows uses backslashes in paths, but they're still
-// interpreted as the escape character when put between quotes.
-constfilename=__filename.replace(/\\/g,'/');
-
-// assert that nothing is written to stdout
-child.exec(nodejs+' --eval 42',
-function(err,stdout,stderr){
-assert.ifError(err);
-assert.strictEqual(stdout,'');
-assert.strictEqual(stderr,'');
-});
-
-// assert that "42\n" is written to stderr
-child.exec(nodejs+' --eval "console.error(42)"',
-function(err,stdout,stderr){
+// Assert that "42\n" is written to stderr.
+child.exec(`${nodejs} --eval "console.error(42)"`,
+common.mustCall((err,stdout,stderr)=>{
 assert.ifError(err);
 assert.strictEqual(stdout,'');
 assert.strictEqual(stderr,'42\n');
-});
-
-// assert that the expected output is written to stdout
-['--print','-p -e','-pe','-p'].forEach(function(s){
-constcmd=nodejs+' '+s+' ';
-
-child.exec(cmd+'42',
-function(err,stdout,stderr){
-assert.ifError(err);
-assert.strictEqual(stdout,'42\n');
-assert.strictEqual(stderr,'');
-});
-
-child.exec(cmd+"'[]'",common.mustCall(
-function(err,stdout,stderr){
-assert.ifError(err);
-assert.strictEqual(stdout,'[]\n');
-assert.strictEqual(stderr,'');
-}));
+}));
+
+// Assert that the expected output is written to stdout.
+['--print','-p -e','-pe','-p'].forEach((s)=>{
+constcmd=`${nodejs}${s} `;
+
+child.exec(`${cmd}42`,common.mustCall((err,stdout,stderr)=>{
+assert.ifError(err);
+assert.strictEqual(stdout,'42\n');
+assert.strictEqual(stderr,'');
+}));
+
+child.exec(`${cmd} '[]'`,common.mustCall((err,stdout,stderr)=>{
+assert.ifError(err);
+assert.strictEqual(stdout,'[]\n');
+assert.strictEqual(stderr,'');
+}));
 });
 
-// assert that module loading works
-child.exec(nodejs+' --eval "require(\''+filename+'\')"',
-function(err,stdout,stderr){
-assert.strictEqual(err.code,42);
-assert.strictEqual(
-stdout,'Loaded as a module, exiting with status code 42.\n');
-assert.strictEqual(stderr,'');
-});
+// Assert that module loading works.
+{
+// Replace \ by / because Windows uses backslashes in paths, but they're still
+// interpreted as the escape character when put between quotes.
+constfilename=__filename.replace(/\\/g,'/');
+
+child.exec(`${nodejs} --eval "require('${filename}')"`,
+common.mustCall((err,stdout,stderr)=>{
+assert.strictEqual(err.code,42);
+assert.strictEqual(
+stdout,'Loaded as a module, exiting with status code 42.\n');
+assert.strictEqual(stderr,'');
+}));
+}
 
 // Check that builtin modules are pre-defined.
-child.exec(nodejs+' --print "os.platform()"',
-function(err,stdout,stderr){
+child.exec(`${nodejs}--print "os.platform()"`,
+common.mustCall((err,stdout,stderr)=>{
 assert.ifError(err);
 assert.strictEqual(stderr,'');
 assert.strictEqual(stdout.trim(),require('os').platform());
-});
+}));
 
-// module path resolve bug, regression test
-child.exec(nodejs+' --eval "require(\'./test/parallel/test-cli-eval.js\')"',
-function(err,stdout,stderr){
+// Module path resolve bug regression test.
+child.exec(`${nodejs}--eval "require('./test/parallel/test-cli-eval.js')"`,
+common.mustCall((err,stdout,stderr)=>{
 assert.strictEqual(err.code,42);
 assert.strictEqual(
 stdout,'Loaded as a module, exiting with status code 42.\n');
 assert.strictEqual(stderr,'');
-});
+}));
 
-// Missing argument should not crash
-child.exec(nodejs+' -e',common.mustCall(function(err,stdout,stderr){
+// Missing argument should not crash.
+child.exec(`${nodejs} -e`,common.mustCall((err,stdout,stderr)=>{
 assert.strictEqual(err.code,9);
 assert.strictEqual(stdout,'');
 assert.strictEqual(stderr.trim(),
 `${process.execPath}: -e requires an argument`);
 }));
 
-// empty program should do nothing
-child.exec(nodejs+' -e ""',function(err,stdout,stderr){
+// Empty program should do nothing.
+child.exec(`${nodejs}-e ""`,common.mustCall((err,stdout,stderr)=>{
 assert.ifError(err);
 assert.strictEqual(stdout,'');
 assert.strictEqual(stderr,'');
-});
+}));
 
-// "\\-42" should be interpreted as an escaped expression, not a switch
-child.exec(nodejs+' -p "\\-42"',
-function(err,stdout,stderr){
-assert.ifError(err);
-assert.strictEqual(stdout,'-42\n');
-assert.strictEqual(stderr,'');
-});
+// "\\-42" should be interpreted as an escaped expression, not a switch.
+child.exec(`${nodejs} -p "\\-42"`,common.mustCall((err,stdout,stderr)=>{
+assert.ifError(err);
+assert.strictEqual(stdout,'-42\n');
+assert.strictEqual(stderr,'');
+}));
 
-child.exec(nodejs+' --use-strict -p process.execArgv',
-function(err,stdout,stderr){
+child.exec(`${nodejs}--use-strict -p process.execArgv`,
+common.mustCall((err,stdout,stderr)=>{
 assert.ifError(err);
 assert.strictEqual(
 stdout,"[ '--use-strict', '-p', 'process.execArgv' ]\n"
 );
 assert.strictEqual(stderr,'');
-});
+}));
 
-// Regression test for https://github.com/nodejs/node/issues/3574
-constemptyFile=path.join(common.fixturesDir,'empty.js');
-child.exec(nodejs+` -e 'require("child_process").fork("${emptyFile}")'`,
-function(err,stdout,stderr){
-assert.ifError(err);
-assert.strictEqual(stdout,'');
-assert.strictEqual(stderr,'');
-});
+// Regression test for https://github.com/nodejs/node/issues/3574.
+{
+constemptyFile=path.join(common.fixturesDir,'empty.js');
+
+child.exec(`${nodejs} -e 'require("child_process").fork("${emptyFile}")'`,
+common.mustCall((err,stdout,stderr)=>{
+assert.ifError(err);
+assert.strictEqual(stdout,'');
+assert.strictEqual(stderr,'');
+}));
+}
 
 // Regression test for https://github.com/nodejs/node/issues/8534.
 {