test_runner: fix coverage report when a directory is named file

The coverage tree traversal checked `tree[key].file` to detect file
entries. When a directory named "file" contained a file also named
"file", this check incorrectly matched the child entry instead of
file metadata, causing a TypeError when accessing `.path`.

Check for `.file?.path` instead to correctly identify file metadata.

Fixes: #61080
PR-URL: #61169
Reviewed-By: Aviv Keller <me@aviv.sh>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>
Reviewed-By: Pietro Marchini <pietro.marchini94@gmail.com>
Reviewed-By: Ulises Gascón <ulisesgascongonzalez@gmail.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>

Author: heathdutton

lib/internal/test_runner/utils.js

@@ -520,7 +520,7 @@ function getCoverageReport(pad, summary, symbol, color, table) {
 
   function printCoverageBodyTree(tree, depth = 0) {
     for (const key in tree) {
-      if (tree[key].file) {
+      if (tree[key].file?.path) {
         const file = tree[key].file;
         const fileName = ArrayPrototypePop(StringPrototypeSplit(file.path, sep));
 

test/fixtures/test-runner/coverage-file-name/file/file

@@ -0,0 +1,4 @@
+'use strict';
+module.exports.fn = function() {
+  return 1;
+};

test/fixtures/test-runner/coverage-file-name/test.js

@@ -0,0 +1,7 @@
+'use strict';
+const { fn } = require('./file/file');
+const test = require('node:test');
+
+test('coverage with file/file directory structure', () => {
+  fn();
+});

test/parallel/test-runner-coverage.js

@@ -489,3 +489,19 @@ test('correctly prints the coverage report of files contained in parent director
   assert(result.stdout.toString().includes(report));
   assert.strictEqual(result.status, 0);
 });
+
+// Regression test for https://github.com/nodejs/node/issues/61080
+test('coverage with directory and file named "file"', skipIfNoInspector, () => {
+  const fixture = fixtures.path('test-runner', 'coverage-file-name', 'test.js');
+  const args = [
+    '--experimental-test-coverage',
+    '--test-reporter',
+    'tap',
+    fixture,
+  ];
+  const result = spawnSync(process.execPath, args);
+
+  assert.strictEqual(result.stderr.toString(), '');
+  assert.strictEqual(result.status, 0);
+  assert(result.stdout.toString().includes('start of coverage report'));
+});