test: add stdio checks to cp-exec-maxBuffer

Expands this test case to check what happens to stdout/stderr when maxBuffer is exceeded. Also changes how cases are checked so that assertion stacks are tracable to their test case, aka 'make it actually debuggable'. PR-URL: #24951 Reviewed-By: Ruben Bridgewater <[email protected]> Reviewed-By: Anna Henningsen <[email protected]>

Author: Fishrock123

test/parallel/test-child-process-exec-maxBuffer.js

@@ -3,12 +3,11 @@ const common = require('../common');
 constassert=require('assert');
 constcp=require('child_process');
 
-functioncheckFactory(streamName){
-returncommon.mustCall((err)=>{
-assert.strictEqual(err.message,`${streamName} maxBuffer length exceeded`);
-assert(errinstanceofRangeError);
-assert.strictEqual(err.code,'ERR_CHILD_PROCESS_STDIO_MAXBUFFER');
-});
+functionrunChecks(err,stdio,streamName,expected){
+assert.strictEqual(err.message,`${streamName} maxBuffer length exceeded`);
+assert(errinstanceofRangeError);
+assert.strictEqual(err.code,'ERR_CHILD_PROCESS_STDIO_MAXBUFFER');
+assert.deepStrictEqual(stdio[streamName],expected);
 }
 
 {
@@ -25,21 +24,39 @@ function checkFactory(streamName){
 {
 constcmd='echo "hello world"';
 
-cp.exec(cmd,{maxBuffer: 5},checkFactory('stdout'));
+cp.exec(
+cmd,
+{maxBuffer: 5},
+common.mustCall((err,stdout,stderr)=>{
+runChecks(err,{ stdout, stderr },'stdout','');
+})
+);
 }
 
 constunicode='中文测试';// length = 4, byte length = 12
 
 {
 constcmd=`"${process.execPath}" -e "console.log('${unicode}');"`;
 
-cp.exec(cmd,{maxBuffer: 10},checkFactory('stdout'));
+cp.exec(
+cmd,
+{maxBuffer: 10},
+common.mustCall((err,stdout,stderr)=>{
+runChecks(err,{ stdout, stderr },'stdout','');
+})
+);
 }
 
 {
 constcmd=`"${process.execPath}" -e "console.error('${unicode}');"`;
 
-cp.exec(cmd,{maxBuffer: 10},checkFactory('stderr'));
+cp.exec(
+cmd,
+{maxBuffer: 3},
+common.mustCall((err,stdout,stderr)=>{
+runChecks(err,{ stdout, stderr },'stderr','');
+})
+);
 }
 
 {
@@ -48,7 +65,10 @@ const unicode = '中文测试' // length = 4, byte length = 12
 constchild=cp.exec(
 cmd,
 {encoding: null,maxBuffer: 10},
-checkFactory('stdout'));
+common.mustCall((err,stdout,stderr)=>{
+runChecks(err,{ stdout, stderr },'stdout','');
+})
+);
 
 child.stdout.setEncoding('utf-8');
 }
@@ -58,8 +78,11 @@ const unicode = '中文测试' // length = 4, byte length = 12
 
 constchild=cp.exec(
 cmd,
-{encoding: null,maxBuffer: 10},
-checkFactory('stderr'));
+{encoding: null,maxBuffer: 3},
+common.mustCall((err,stdout,stderr)=>{
+runChecks(err,{ stdout, stderr },'stderr','');
+})
+);
 
 child.stderr.setEncoding('utf-8');
 }