util: fix test to prevent styleText color from changing

lib/internal/test_runner/runner.js

@@ -373,7 +373,7 @@ function runTestFile(path, filesWatcher, opts) {
       env.WATCH_REPORT_DEPENDENCIES = '1';
     }
     if (opts.root.harness.shouldColorizeTestFiles) {
-      env.FORCE_COLOR = '1';
+      env.NODE_TEST_CONTEXT = 'child-v8-test-colorize';
     }
 
     const child = spawn(

lib/internal/test_runner/utils.js

@@ -203,7 +203,8 @@ function parseCommandLine() {
   const watch = getOptionValue('--watch');
   const timeout = getOptionValue('--test-timeout') || Infinity;
   const isChildProcess = process.env.NODE_TEST_CONTEXT === 'child';
-  const isChildProcessV8 = process.env.NODE_TEST_CONTEXT === 'child-v8';
+  const isChildProcessV8 = process.env.NODE_TEST_CONTEXT === 'child-v8' ||
+   process.env.NODE_TEST_CONTEXT === 'child-v8-test-colorize';
   let globalSetupPath;
   let concurrency;
   let coverageExcludeGlobs;

lib/internal/util/colors.js

@@ -15,7 +15,10 @@ module.exports = {
   clear: '',
   reset: '',
   hasColors: false,
-  shouldColorize(stream) {
+  shouldColorize(stream, ignoreTestContext = false) {
+    if (!ignoreTestContext && process.env.NODE_TEST_CONTEXT === 'child-v8-test-colorize') {
+      return lazyInternalTTY().getColorDepth() > 2;
+    }
     if (process.env.FORCE_COLOR !== undefined) {
       return lazyInternalTTY().getColorDepth() > 2;
     }

lib/util.js

@@ -130,7 +130,12 @@ function styleText(format, text, { validateStream = true, stream = process.stdou
     }
 
     // If the stream is falsy or should not be colorized, set skipColorize to true
-    skipColorize = !lazyUtilColors().shouldColorize(stream);
+    skipColorize = !lazyUtilColors().shouldColorize(
+      stream,
+      // Avoid styleText color changes in tests
+      // https://github.com/nodejs/node/issues/57921
+      stream !== process.stdout && stream !== process.stderr,
+    );
   }
 
   // If the format is not an array, convert it to an array

test/fixtures/test-runner/force-color.js

@@ -0,0 +1,5 @@
+const {WriteStream} = require('tty');
+const assert = require('assert');
+
+assert.strictEqual(process.env.FORCE_COLOR, '3');
+assert.strictEqual(WriteStream(0).getColorDepth(), 24);

test/fixtures/test-runner/output/style-text-output-in-test-tty.mjs

@@ -0,0 +1,14 @@
+import { Writable } from 'node:stream';
+import { styleText } from 'node:util';
+
+const streamTTY = new class extends Writable {
+  isTTY = true;
+}();
+const streamNoTTY = new class extends Writable {
+  isTTY = false;
+}();
+
+console.log(styleText('bgYellow', 'TTY', { stream: streamTTY }));
+console.log(styleText('bgYellow', 'No TTY', { stream: streamNoTTY }));
+console.log(styleText('bgYellow', 'stdout', { stream: process.stdout }));
+console.log(styleText('bgYellow', 'stderr', { stream: process.stderr }));

test/fixtures/test-runner/output/style-text-output-in-test-tty.snapshot

@@ -0,0 +1,20 @@
+TAP version 13
+# [43mTTY[49m
+# No TTY
+# [43mstdout[49m
+# [43mstderr[49m
+# Subtest: /test/fixtures/test-runner/output/style-text-output-in-test-tty.mjs
+ok 1 - /test/fixtures/test-runner/output/style-text-output-in-test-tty.mjs
+  ---
+  duration_ms: *
+  type: 'test'
+  ...
+1..1
+# tests 1
+# suites 0
+# pass 1
+# fail 0
+# cancelled 0
+# skipped 0
+# todo 0
+# duration_ms *

test/fixtures/test-runner/output/style-text-output-in-test.mjs

@@ -0,0 +1,14 @@
+import { Writable } from 'node:stream';
+import { styleText } from 'node:util';
+
+const streamTTY = new class extends Writable {
+  isTTY = true;
+}();
+const streamNoTTY = new class extends Writable {
+  isTTY = false;
+}();
+
+console.log(styleText('bgYellow', 'TTY', { stream: streamTTY }));
+console.log(styleText('bgYellow', 'No TTY', { stream: streamNoTTY }));
+console.log(styleText('bgYellow', 'stdout', { stream: process.stdout }));
+console.log(styleText('bgYellow', 'stderr', { stream: process.stderr }));

test/fixtures/test-runner/output/style-text-output-in-test.snapshot

@@ -0,0 +1,20 @@
+TAP version 13
+# TTY
+# No TTY
+# stdout
+# stderr
+# Subtest: /test/fixtures/test-runner/output/style-text-output-in-test.mjs
+ok 1 - /test/fixtures/test-runner/output/style-text-output-in-test.mjs
+  ---
+  duration_ms: *
+  type: 'test'
+  ...
+1..1
+# tests 1
+# suites 0
+# pass 1
+# fail 0
+# cancelled 0
+# skipped 0
+# todo 0
+# duration_ms *

test/parallel/test-runner-force-color.mjs

@@ -0,0 +1,15 @@
+import * as common from '../common/index.mjs';
+import * as fixtures from '../common/fixtures.js';
+import assert from 'node:assert';
+
+common.spawnPromisified(process.execPath, [
+  '--test',
+  fixtures.path('test-runner', 'force-color.js'),
+], {
+  env: {
+    ...process.env,
+    FORCE_COLOR: 3,
+  }
+}).then(common.mustCall((result) => {
+  assert.strictEqual(result.code, 0);
+}));

test/parallel/test-runner-output.mjs

@@ -313,6 +313,15 @@ const tests = [
     flags: ['--test-reporter=tap', '--test-coverage-exclude=../output/**'],
     cwd: fixtures.path('test-runner/coverage-snap'),
   } : false,
+  canColorize ? {
+    name: 'test-runner/output/style-text-output-in-test.mjs',
+    flags: ['--test', '--test-reporter=tap'],
+  } : false,
+  canColorize ? {
+    name: 'test-runner/output/style-text-output-in-test-tty.mjs',
+    flags: ['--test', '--test-reporter=tap'],
+    tty: true,
+  } : false,
 ]
 .filter(Boolean)
 .map(({ flags, name, tty, transform, cwd }) => ({