test_runner: omit inaccessible files from coverage

If V8 generates code coverage for a file that is later
inaccessible to the test runner, then omit that file from the
coverage report.
PR-URL: #47850
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Beth Griggs <bethanyngriggs@gmail.com>

Author: cjihrig

lib/internal/test_runner/coverage.js

@@ -99,7 +99,16 @@ class TestCoverage {
 // original line endings because those characters are necessary for
 // determining offsets in the file.
 constfilePath=fileURLToPath(url);
-constsource=readFileSync(filePath,'utf8');
+letsource;
+
+try{
+source=readFileSync(filePath,'utf8');
+}catch{
+// The file can no longer be read. It may have been deleted among
+// other possibilities. Leave it out of the coverage report.
+continue;
+}
+
 constlinesWithBreaks=
 RegExpPrototypeSymbolSplit(kLineSplitRegex,source);
 letignoreCount=0;

test/fixtures/v8-coverage/combined_coverage/third.test.js

@@ -1,8 +1,25 @@
 'use strict';
+constassert=require('node:assert');
+const{ unlinkSync, writeFileSync }=require('node:fs')
+const{ join }=require('node:path');
 const{ test }=require('node:test');
 constcommon=require('./common');
 
 test('third 1',()=>{
 common.fnC(1,4);
 common.fnD(99);
 });
+
+assert(process.env.NODE_TEST_TMPDIR);
+consttmpFilePath=join(process.env.NODE_TEST_TMPDIR,'temp-module.js');
+writeFileSync(tmpFilePath,`
+ module.exports = {
+ fn() {
+ return 42;
+ }
+ };
+`);
+consttempModule=require(tmpFilePath);
+assert.strictEqual(tempModule.fn(),42);
+// Deleted files should not be part of the coverage report.
+unlinkSync(tmpFilePath);

test/parallel/test-runner-coverage.js

@@ -156,7 +156,7 @@ test('coverage is combined for multiple processes', skipIfNoInspector, () => {
 '| 100.00 | 100.00 | ',
 '# test/fixtures/v8-coverage/combined_coverage/third.test.js | 100.00 | '+
 '100.00 | 100.00 | ',
-'# all files | 90.72 | 72.73 | 88.89 |',
+'# all files | 92.11 | 72.73 | 88.89 |',
 '# end of coverage report',
 ].join('\n');
 
@@ -168,7 +168,9 @@ test('coverage is combined for multiple processes', skipIfNoInspector, () => {
 constargs=[
 '--test','--experimental-test-coverage','--test-reporter','tap',fixture,
 ];
-constresult=spawnSync(process.execPath,args);
+constresult=spawnSync(process.execPath,args,{
+env: { ...process.env,NODE_TEST_TMPDIR: tmpdir.path}
+});
 
 assert.strictEqual(result.stderr.toString(),'');
 assert(result.stdout.toString().includes(report));