test_runner: add junit reporter

doc/api/test.md

@@ -632,6 +632,9 @@ The following built-reporters are supported:
   where each passing test is represented by a `.`,
   and each failing test is represented by a `X`.
 
+* `junit`
+  The junit reporter outputs test results in a jUnit XML format
+
 When `stdout` is a [TTY][], the `spec` reporter is used by default.
 Otherwise, the `tap` reporter is used by default.
 
@@ -643,11 +646,11 @@ to the test runner's output is required, use the events emitted by the
 The reporters are available via the `node:test/reporters` module:
 
 ```mjs
-import { tap, spec, dot } from 'node:test/reporters';
+import { tap, spec, dot, junit } from 'node:test/reporters';
 ```
 
 ```cjs
-const { tap, spec, dot } = require('node:test/reporters');
+const { tap, spec, dot, junit } = require('node:test/reporters');
 ```
 
 ### Custom reporters

lib/internal/test_runner/reporter/junit.js

@@ -0,0 +1,158 @@
+'use strict';
+const {
+  ArrayPrototypeFilter,
+  ArrayPrototypeMap,
+  ArrayPrototypeJoin,
+  ArrayPrototypePush,
+  ArrayPrototypeSome,
+  NumberPrototypeToFixed,
+  ObjectEntries,
+  RegExpPrototypeSymbolReplace,
+  String,
+  StringPrototypeRepeat,
+} = primordials;
+
+const { inspectWithNoCustomRetry } = require('internal/errors');
+const { hostname } = require('os');
+
+const inspectOptions = { __proto__: null, colors: false, breakLength: Infinity };
+const HOSTNAME = hostname();
+
+function escapeAttribute(s = '') {
+  return escapeContent(RegExpPrototypeSymbolReplace(/"/g, RegExpPrototypeSymbolReplace(/\n/g, s, ''), '"'));
+}
+
+function escapeContent(s = '') {
+  return RegExpPrototypeSymbolReplace(/</g, RegExpPrototypeSymbolReplace(/&/g, s, '&amp;'), '&lt;');
+}
+
+function escapeComment(s = '') {
+  return RegExpPrototypeSymbolReplace(/--/g, s, '&#45;&#45;');
+}
+
+function treeToXML(tree) {
+  if (typeof tree === 'string') {
+    return `${escapeContent(tree)}\n`;
+  }
+  const {
+    tag, attrs, nesting, children, comment,
+  } = tree;
+  const indent = StringPrototypeRepeat('\t', nesting + 1);
+  if (comment) {
+    return `${indent}<!-- ${escapeComment(comment)} -->\n`;
+  }
+  const attrsString = ArrayPrototypeJoin(ArrayPrototypeMap(ObjectEntries(attrs)
+    , ({ 0: key, 1: value }) => `${key}="${escapeAttribute(String(value))}"`)
+  , ' ');
+  if (!children?.length) {
+    return `${indent}<${tag} ${attrsString}/>\n`;
+  }
+  const childrenString = ArrayPrototypeJoin(ArrayPrototypeMap(children ?? [], treeToXML), '');
+  return `${indent}<${tag} ${attrsString}>\n${childrenString}${indent}</${tag}>\n`;
+}
+
+function isFailure(node) {
+  return (node?.children && ArrayPrototypeSome(node.children, (c) => c.tag === 'failure')) || node?.attrs?.failures;
+}
+
+function isSkipped(node) {
+  return (node?.children && ArrayPrototypeSome(node.children, (c) => c.tag === 'skipped')) || node?.attrs?.failures;
+}
+
+module.exports = async function* junitReporter(source) {
+  yield '<?xml version="1.0" encoding="utf-8"?>\n';
+  yield '<testsuites>\n';
+  let currentSuite = null;
+  const roots = [];
+
+  function startTest(event) {
+    const originalSuite = currentSuite;
+    currentSuite = {
+      __proto__: null,
+      attrs: { __proto__: null, name: event.data.name },
+      nesting: event.data.nesting,
+      parent: currentSuite,
+      children: [],
+    };
+    if (originalSuite?.children) {
+      ArrayPrototypePush(originalSuite.children, currentSuite);
+    }
+    if (!currentSuite.parent) {
+      ArrayPrototypePush(roots, currentSuite);
+    }
+  }
+
+  for await (const event of source) {
+    switch (event.type) {
+      case 'test:start': {
+        startTest(event);
+        break;
+      }
+      case 'test:pass':
+      case 'test:fail': {
+        if (!currentSuite) {
+          startTest({ __proto__: null, data: { __proto__: null, name: 'root', nesting: 0 } });
+        }
+        if (currentSuite.attrs.name !== event.data.name ||
+          currentSuite.nesting !== event.data.nesting) {
+          startTest(event);
+        }
+        const currentTest = currentSuite;
+        if (currentSuite?.nesting === event.data.nesting) {
+          currentSuite = currentSuite.parent;
+        }
+        currentTest.attrs.time = NumberPrototypeToFixed(event.data.details.duration_ms / 1000, 6);
+        const nonCommentChildren = ArrayPrototypeFilter(currentTest.children, (c) => c.comment == null);
+        if (nonCommentChildren.length > 0) {
+          currentTest.tag = 'testsuite';
+          currentTest.attrs.disabled = 0;
+          currentTest.attrs.errors = 0;
+          currentTest.attrs.tests = nonCommentChildren.length;
+          currentTest.attrs.failures = ArrayPrototypeFilter(currentTest.children, isFailure).length;
+          currentTest.attrs.skipped = ArrayPrototypeFilter(currentTest.children, isSkipped).length;
+          currentTest.attrs.hostname = HOSTNAME;
+        } else {
+          currentTest.tag = 'testcase';
+          currentTest.attrs.classname = event.data.classname ?? 'test';
+          if (event.data.skip) {
+            ArrayPrototypePush(currentTest.children, {
+              __proto__: null, nesting: event.data.nesting + 1, tag: 'skipped',
+              attrs: { __proto__: null, type: 'skipped', message: event.data.skip },
+            });
+          }
+          if (event.data.todo) {
+            ArrayPrototypePush(currentTest.children, {
+              __proto__: null, nesting: event.data.nesting + 1, tag: 'skipped',
+              attrs: { __proto__: null, type: 'todo', message: event.data.todo },
+            });
+          }
+          if (event.type === 'test:fail') {
+            const error = event.data.details?.error;
+            currentTest.children.push({
+              __proto__: null,
+              nesting: event.data.nesting + 1,
+              tag: 'failure',
+              attrs: { __proto__: null, type: error?.failureType || error?.code, message: error?.message ?? '' },
+              children: [inspectWithNoCustomRetry(error, inspectOptions)],
+            });
+            currentTest.failures = 1;
+            currentTest.attrs.failure = error?.message ?? '';
+          }
+        }
+        break;
+      }
+      case 'test:diagnostic': {
+        const parent = currentSuite?.children ?? roots;
+        ArrayPrototypePush(parent, {
+          __proto__: null, nesting: event.data.nesting, comment: event.data.message,
+        });
+        break;
+      } default:
+        break;
+    }
+  }
+  for (const suite of roots) {
+    yield treeToXML(suite);
+  }
+  yield '</testsuites>\n';
+};

lib/internal/test_runner/utils.js

@@ -110,6 +110,7 @@ const kBuiltinReporters = new SafeMap([
   ['spec', 'internal/test_runner/reporter/spec'],
   ['dot', 'internal/test_runner/reporter/dot'],
   ['tap', 'internal/test_runner/reporter/tap'],
+  ['junit', 'internal/test_runner/reporter/junit'],
 ]);
 
 const kDefaultReporter = process.stdout.isTTY ? 'spec' : 'tap';

lib/test/reporters.js

@@ -3,6 +3,7 @@
 const { ObjectDefineProperties, ReflectConstruct } = primordials;
 
 let dot;
+let junit;
 let spec;
 let tap;
 
@@ -17,6 +18,15 @@ ObjectDefineProperties(module.exports, {
       return dot;
     },
   },
+  junit: {
+    __proto__: null,
+    configurable: true,
+    enumerable: true,
+    get() {
+      junit ??= require('internal/test_runner/reporter/junit');
+      return junit;
+    },
+  },
   spec: {
     __proto__: null,
     configurable: true,

test/fixtures/test-runner/output/junit_reporter.js

@@ -0,0 +1,7 @@
+'use strict';
+require('../../../common');
+const fixtures = require('../../../common/fixtures');
+const spawn = require('node:child_process').spawn;
+
+spawn(process.execPath,
+      ['--no-warnings', '--test-reporter', 'junit', fixtures.path('test-runner/output/output.js')], { stdio: 'inherit' });