test_runner: add context.fullName

This commit adds a fullName getter to the TestContext and
SuiteContext classes. This is similar to the existing name getter,
but also includes the name of all ancestor tests/suites.

doc/api/test.md

@@ -3050,6 +3050,14 @@ test('top level test', (t) => {
 });
 ```
 
+### `context.fullName`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+The name of the test and each of its ancestors, separated by `>`.
+
 ### `context.name`
 
 <!-- YAML

lib/internal/test_runner/test.js

@@ -218,6 +218,10 @@ class TestContext {
     return this.#test.name;
   }
 
+  get fullName() {
+    return getFullName(this.#test);
+  }
+
   get error() {
     return this.#test.error;
   }
@@ -331,6 +335,10 @@ class SuiteContext {
   get name() {
     return this.#suite.name;
   }
+
+  get fullName() {
+    return getFullName(this.#suite);
+  }
 }
 
 class Test extends AsyncResource {
@@ -1216,6 +1224,16 @@ class Suite extends Test {
   }
 }
 
+function getFullName(test) {
+  let fullName = test.name;
+
+  for (let t = test.parent; t !== t.root; t = t.parent) {
+    fullName = `${t.name} > ${fullName}`;
+  }
+
+  return fullName;
+}
+
 module.exports = {
   kCancelledByParent,
   kSubtestsFailed,

test/parallel/test-runner-test-fullname.js

@@ -0,0 +1,24 @@
+'use strict';
+require('../common');
+const { strictEqual } = require('node:assert');
+const { suite, test } = require('node:test');
+
+suite('suite', (t) => {
+  strictEqual(t.fullName, 'suite');
+
+  test('test', (t) => {
+    strictEqual(t.fullName, 'suite > test');
+
+    t.test('subtest', (t) => {
+      strictEqual(t.fullName, 'suite > test > subtest');
+
+      t.test('subsubtest', (t) => {
+        strictEqual(t.fullName, 'suite > test > subtest > subsubtest');
+      });
+    });
+  });
+});
+
+test((t) => {
+  strictEqual(t.fullName, '<anonymous>');
+});