test_runner: add context.filePath

This commit adds a filePath getter to the TestContext and
SuiteContext classes. This allows a context to be mapped back to
the original test file that created it, even if it was imported
from another file. This is useful for mapping features like test
snapshots to the correct test file. This is also prep work for
supporting running test files in the test runner process.

PR-URL: https://github.com/nodejs/node/pull/53853
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

doc/api/test.md

@@ -3204,6 +3204,16 @@ test('top level test', (t) => {
 });
 ```
 
+### `context.filePath`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+The absolute path of the test file that created the current test. If a test file
+imports additional modules that generate tests, the imported tests will return
+the path of the root test file.
+
 ### `context.fullName`
 
 <!-- YAML
@@ -3438,6 +3448,16 @@ An instance of `SuiteContext` is passed to each suite function in order to
 interact with the test runner. However, the `SuiteContext` constructor is not
 exposed as part of the API.
 
+### `context.filePath`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+The absolute path of the test file that created the current suite. If a test
+file imports additional modules that generate suites, the imported suites will
+return the path of the root test file.
+
 ### `context.name`
 
 <!-- YAML

lib/internal/test_runner/harness.js

@@ -221,7 +221,7 @@ let globalRoot;
 let reportersSetup;
 function getGlobalRoot() {
   if (!globalRoot) {
-    globalRoot = createTestTree();
+    globalRoot = createTestTree({ __proto__: null, entryFile: process.argv?.[1] });
     globalRoot.reporter.on('test:fail', (data) => {
       if (data.todo === undefined || data.todo === false) {
         process.exitCode = kGenericUserError;

lib/internal/test_runner/test.js

@@ -225,6 +225,10 @@ class TestContext {
     return this.#test.name;
   }
 
+  get filePath() {
+    return this.#test.entryFile;
+  }
+
   get fullName() {
     return getFullName(this.#test);
   }
@@ -343,6 +347,10 @@ class SuiteContext {
     return this.#suite.name;
   }
 
+  get filePath() {
+    return this.#suite.entryFile;
+  }
+
   get fullName() {
     return getFullName(this.#suite);
   }
@@ -357,7 +365,7 @@ class Test extends AsyncResource {
     super('Test');
 
     let { fn, name, parent } = options;
-    const { concurrency, loc, only, timeout, todo, skip, signal, plan } = options;
+    const { concurrency, entryFile, loc, only, timeout, todo, skip, signal, plan } = options;
 
     if (typeof fn !== 'function') {
       fn = noop;
@@ -386,6 +394,7 @@ class Test extends AsyncResource {
       this.runOnlySubtests = this.only;
       this.childNumber = 0;
       this.timeout = kDefaultTimeout;
+      this.entryFile = entryFile;
       this.root = this;
       this.hooks = {
         __proto__: null,
@@ -406,6 +415,7 @@ class Test extends AsyncResource {
       this.runOnlySubtests = !this.only;
       this.childNumber = parent.subtests.length + 1;
       this.timeout = parent.timeout;
+      this.entryFile = parent.entryFile;
       this.root = parent.root;
       this.hooks = {
         __proto__: null,

test/parallel/test-runner-test-filepath.js

@@ -0,0 +1,52 @@
+'use strict';
+require('../common');
+const tmpdir = require('../common/tmpdir');
+const { strictEqual } = require('node:assert');
+const { writeFileSync } = require('node:fs');
+const { suite, test } = require('node:test');
+
+tmpdir.refresh();
+
+suite('suite', (t) => {
+  strictEqual(t.filePath, __filename);
+
+  test('test', (t) => {
+    strictEqual(t.filePath, __filename);
+
+    t.test('subtest', (t) => {
+      strictEqual(t.filePath, __filename);
+
+      t.test('subsubtest', (t) => {
+        strictEqual(t.filePath, __filename);
+      });
+    });
+  });
+});
+
+test((t) => {
+  strictEqual(t.filePath, __filename);
+});
+
+const importedTestFile = tmpdir.resolve('temp.js');
+writeFileSync(importedTestFile, `
+  'use strict';
+  const { strictEqual } = require('node:assert');
+  const { suite, test } = require('node:test');
+
+  suite('imported suite', (t) => {
+    strictEqual(t.filePath, ${JSON.stringify(__filename)});
+
+    test('imported test', (t) => {
+      strictEqual(t.filePath, ${JSON.stringify(__filename)});
+
+      t.test('imported subtest', (t) => {
+        strictEqual(t.filePath, ${JSON.stringify(__filename)});
+
+        t.test('imported subsubtest', (t) => {
+          strictEqual(t.filePath, ${JSON.stringify(__filename)});
+        });
+      });
+    });
+  });
+`);
+require(importedTestFile);