Migrate Mocha and test configuration to v12

.github/workflows/build.yml

@@ -17,7 +17,7 @@ env:
   # Unicode characters are causing 2.7 failures so skip that for now.
   special-working-directory: './path with spaces'
   special-working-directory-relative: 'path with spaces'
-  # Use the mocha-multi-reporters and send output to both console (spec) and JUnit (mocha-junit-reporter).
+  # Send output to both console (spec) and JUnit-compatible XML.
   # Also enables a reporter which exits the process running the tests if it haven't already.
   MOCHA_REPORTER_JUNIT: true
 

.github/workflows/pr-check.yml

@@ -12,7 +12,7 @@ permissions: {}
 env:
   NODE_VERSION: 22.21.1
   PYTHON_VERSION: '3.10' # YML treats 3.10 the number as 3.1, so quotes around 3.10
-  MOCHA_REPORTER_JUNIT: true # Use the mocha-multi-reporters and send output to both console (spec) and JUnit (mocha-junit-reporter). Also enables a reporter which exits the process running the tests if it haven't already.
+  MOCHA_REPORTER_JUNIT: true # Send output to both console (spec) and JUnit-compatible XML. Also enables the test completion reporter.
   ARTIFACT_NAME_VSIX: ms-python-insiders-vsix
   TEST_RESULTS_DIRECTORY: .
   # Force a path with spaces and to test extension works in these scenarios

.vscode/launch.json

@@ -140,12 +140,12 @@
             "name": "Unit Tests (without VS Code, *.unit.test.ts)",
             "type": "node",
             "request": "launch",
-            "program": "${workspaceFolder}/node_modules/mocha/bin/_mocha",
+            "program": "${workspaceFolder}/node_modules/mocha/bin/mocha.js",
             "stopOnEntry": false,
             "sourceMaps": true,
             "args": [
                 "./out/test/**/*.unit.test.js",
-                "--require=out/test/unittests.js",
+                "--require=./out/test/unittests.js",
                 "--ui=tdd",
                 "--recursive",
                 "--colors",
@@ -160,12 +160,12 @@
             "name": "Unit Tests (fast, without VS Code and without react/monaco, *.unit.test.ts)",
             "type": "node",
             "request": "launch",
-            "program": "${workspaceFolder}/node_modules/mocha/bin/_mocha",
+            "program": "${workspaceFolder}/node_modules/mocha/bin/mocha.js",
             "stopOnEntry": false,
             "sourceMaps": true,
             "args": [
                 "./out/test/**/*.unit.test.js",
-                "--require=out/test/unittests.js",
+                "--require=./out/test/unittests.js",
                 "--ui=tdd",
                 "--recursive",
                 "--colors",
@@ -181,12 +181,12 @@
             "name": "Functional Tests (without VS Code, *.functional.test.ts)",
             "type": "node",
             "request": "launch",
-            "program": "${workspaceFolder}/node_modules/mocha/bin/_mocha",
+            "program": "${workspaceFolder}/node_modules/mocha/bin/mocha.js",
             "stopOnEntry": false,
             "sourceMaps": true,
             "args": [
                 "./out/test/**/*.functional.test.js",
-                "--require=out/test/unittests.js",
+                "--require=./out/test/unittests.js",
                 "--ui=tdd",
                 "--recursive",
                 "--colors",

build/.mocha.functional.json

@@ -1,11 +1,10 @@
 {
     "spec": "./out/test/**/*.functional.test.js",
     "require": [
-        "out/test/unittests.js"
+        "./out/test/unittests.js"
     ],
     "exclude": "out/**/*.jsx",
-    "reporter": "mocha-multi-reporters",
-    "reporter-option": "configFile=./build/.mocha-multi-reporters.config",
+    "reporter": "./build/ci/scripts/ci_reporter.js",
     "ui": "tdd",
     "recursive": true,
     "colors": true,

build/.mocha.functional.perf.json

@@ -1,7 +1,7 @@
 {
     "spec": "./out/test/**/*.functional.test.js",
-    "exclude-out": "out/**/*.jsx",
-    "require": ["out/test/unittests.js"],
+    "exclude": "out/**/*.jsx",
+    "require": ["./out/test/unittests.js"],
     "reporter": "spec",
     "ui": "tdd",
     "recursive": true,

build/.mocha.performance.json

@@ -1,8 +1,8 @@
 {
     "spec": "./out/test/**/*.functional.test.js",
-    "require": ["out/test/unittests.js"],
-    "reporter": "mocha-multi-reporters",
-    "reporter-option": "configFile=build/.mocha.perf.config",
+    "require": ["./out/test/unittests.js"],
+    "reporter": "./build/ci/scripts/ci_reporter.js",
+    "reporter-option": "output=xunit-test-results.xml",
     "ui": "tdd",
     "recursive": true,
     "colors": true,

build/.mocha.unittests.js.json

@@ -1,8 +1,7 @@
 {
     "spec": "./out/test/**/*.unit.test.js",
-    "require": ["source-map-support/register", "out/test/unittests.js"],
-    "reporter": "mocha-multi-reporters",
-    "reporter-option": "configFile=build/.mocha-multi-reporters.config",
+    "require": ["source-map-support/register", "./out/test/unittests.js"],
+    "reporter": "./build/ci/scripts/ci_reporter.js",
     "ui": "tdd",
     "recursive": true,
     "colors": true

build/.mocha.unittests.json

@@ -1,11 +1,10 @@
 {
     "spec": "./out/test/**/*.unit.test.js",
     "require": [
-        "out/test/unittests.js"
+        "./out/test/unittests.js"
     ],
     "exclude": "out/**/*.jsx",
-    "reporter": "mocha-multi-reporters",
-    "reporter-option": "configFile=./build/.mocha-multi-reporters.config",
+    "reporter": "./build/ci/scripts/ci_reporter.js",
     "ui": "tdd",
     "recursive": true,
     "colors": true,

build/.mocha.unittests.ts.json

@@ -1,8 +1,7 @@
 {
     "spec": "./src/test/**/*.unit.test.ts",
-    "require": ["ts-node/register", "out/test/unittests.js"],
-    "reporter": "mocha-multi-reporters",
-    "reporter-option": "configFile=build/.mocha-multi-reporters.config",
+    "require": ["ts-node/register/files", "./out/test/unittests.js"],
+    "reporter": "./build/ci/scripts/ci_reporter.js",
     "ui": "tdd",
     "recursive": true,
     "colors": true

build/ci/scripts/ci_reporter.js

@@ -0,0 +1,31 @@
+'use strict';
+
+const { reporters } = require('mocha');
+const Spec = require('./spec_with_pid');
+
+class CIReporter extends reporters.XUnit {
+    constructor(runner, options = {}) {
+        const reporterOptions = options.reporterOptions || {};
+        super(runner, {
+            ...options,
+            reporterOptions: {
+                ...reporterOptions,
+                output: reporterOptions.output || process.env.MOCHA_FILE || 'test-results.xml',
+            },
+        });
+        const ConsoleReporter = reporterOptions.consoleReporter ? require(reporterOptions.consoleReporter) : Spec;
+        this.consoleReporter = new ConsoleReporter(runner, options);
+    }
+
+    done(failures, callback) {
+        super.done(failures, () => {
+            if (this.consoleReporter.done) {
+                this.consoleReporter.done(failures, callback);
+            } else {
+                callback(failures);
+            }
+        });
+    }
+}
+
+module.exports = CIReporter;

build/ci/scripts/spec_with_pid.js

@@ -7,8 +7,9 @@
  * Module dependencies.
  */
 
-const Base = require('mocha/lib/reporters/base');
-const { constants } = require('mocha/lib/runner');
+const { reporters, Runner } = require('mocha');
+const { Base } = reporters;
+const { constants } = Runner;
 
 const { EVENT_RUN_BEGIN } = constants;
 const { EVENT_RUN_END } = constants;
@@ -17,7 +18,6 @@ const { EVENT_SUITE_END } = constants;
 const { EVENT_TEST_FAIL } = constants;
 const { EVENT_TEST_PASS } = constants;
 const { EVENT_TEST_PENDING } = constants;
-const { inherits } = require('mocha/lib/utils');
 
 const { color } = Base;
 
@@ -33,65 +33,62 @@ const prefix = process.env.VSC_PYTHON_CI_TEST_PARALLEL ? `${process.pid}   ` : '
  * @param {Runner} runner - Instance triggers reporter actions.
  * @param {Object} [options] - runner options
  */
-function Spec(runner, options) {
-    Base.call(this, runner, options);
+class Spec extends Base {
+    constructor(runner, options) {
+        super(runner, options);
 
-    let indents = 0;
-    let n = 0;
+        let indents = 0;
+        let n = 0;
 
-    function indent() {
-        return Array(indents).join('  ');
-    }
-
-    runner.on(EVENT_RUN_BEGIN, () => {
-        Base.consoleLog();
-    });
-
-    runner.on(EVENT_SUITE_BEGIN, (suite) => {
-        indents += 1;
-        Base.consoleLog(color('suite', `${prefix}%s%s`), indent(), suite.title);
-    });
-
-    runner.on(EVENT_SUITE_END, () => {
-        indents -= 1;
-        if (indents === 1) {
-            Base.consoleLog();
+        function indent() {
+            return Array(indents).join('  ');
         }
-    });
-
-    runner.on(EVENT_TEST_PENDING, (test) => {
-        const fmt = indent() + color('pending', `${prefix} %s`);
-        Base.consoleLog(fmt, test.title);
-    });
 
-    runner.on(EVENT_TEST_PASS, (test) => {
-        let fmt;
-        if (test.speed === 'fast') {
-            fmt = indent() + color('checkmark', prefix + Base.symbols.ok) + color('pass', ' %s');
+        runner.on(EVENT_RUN_BEGIN, () => {
+            Base.consoleLog();
+        });
+
+        runner.on(EVENT_SUITE_BEGIN, (suite) => {
+            indents += 1;
+            Base.consoleLog(color('suite', `${prefix}%s%s`), indent(), suite.title);
+        });
+
+        runner.on(EVENT_SUITE_END, () => {
+            indents -= 1;
+            if (indents === 1) {
+                Base.consoleLog();
+            }
+        });
+
+        runner.on(EVENT_TEST_PENDING, (test) => {
+            const fmt = indent() + color('pending', `${prefix} %s`);
             Base.consoleLog(fmt, test.title);
-        } else {
-            fmt =
-                indent() +
-                color('checkmark', prefix + Base.symbols.ok) +
-                color('pass', ' %s') +
-                color(test.speed, ' (%dms)');
-            Base.consoleLog(fmt, test.title, test.duration);
-        }
-    });
-
-    runner.on(EVENT_TEST_FAIL, (test) => {
-        n += 1;
-        Base.consoleLog(indent() + color('fail', `${prefix}%d) %s`), n, test.title);
-    });
-
-    runner.once(EVENT_RUN_END, this.epilogue.bind(this));
+        });
+
+        runner.on(EVENT_TEST_PASS, (test) => {
+            let fmt;
+            if (test.speed === 'fast') {
+                fmt = indent() + color('checkmark', prefix + Base.symbols.ok) + color('pass', ' %s');
+                Base.consoleLog(fmt, test.title);
+            } else {
+                fmt =
+                    indent() +
+                    color('checkmark', prefix + Base.symbols.ok) +
+                    color('pass', ' %s') +
+                    color(test.speed, ' (%dms)');
+                Base.consoleLog(fmt, test.title, test.duration);
+            }
+        });
+
+        runner.on(EVENT_TEST_FAIL, (test) => {
+            n += 1;
+            Base.consoleLog(indent() + color('fail', `${prefix}%d) %s`), n, test.title);
+        });
+
+        runner.once(EVENT_RUN_END, this.epilogue.bind(this));
+    }
 }
 
-/**
- * Inherit from `Base.prototype`.
- */
-inherits(Spec, Base);
-
 Spec.description = 'hierarchical & verbose [default]';
 
 /**