test_runner: support defining test reporter in NODE_OPTIONS

doc/api/cli.md

@@ -2119,6 +2119,8 @@ Node.js options that are allowed are:
 * `--secure-heap`
 * `--snapshot-blob`
 * `--test-only`
+* `--test-reporter-destination`
+* `--test-reporter`
 * `--throw-deprecation`
 * `--title`
 * `--tls-cipher-list`
@@ -2260,6 +2262,11 @@ If `value` equals `'1'`, the check for a supported platform is skipped during
 Node.js startup. Node.js might not execute correctly. Any issues encountered
 on unsupported platforms will not be fixed.
 
+### `NODE_TEST_CONTEXT=value`
+
+If `value` equals `'child'`, test reporter options will be overridden and test
+output will be sent to stdout in the TAP format.
+
 ### `NODE_TLS_REJECT_UNAUTHORIZED=value`
 
 If `value` equals `'0'`, certificate validation is disabled for TLS connections.

lib/internal/test_runner/runner.js

@@ -145,6 +145,7 @@ function getRunArgs({ path, inspectPort }) {
     ArrayPrototypePush(argv, `--inspect-port=${getInspectPort(inspectPort)}`);
   }
   ArrayPrototypePush(argv, path);
+
   return argv;
 }
 
@@ -260,7 +261,7 @@ function runTestFile(path, root, inspectPort, filesWatcher) {
   const subtest = root.createSubtest(FileTest, path, async (t) => {
     const args = getRunArgs({ path, inspectPort });
     const stdio = ['pipe', 'pipe', 'pipe'];
-    const env = { ...process.env };
+    const env = { ...process.env, NODE_TEST_CONTEXT: 'child' };
     if (filesWatcher) {
       stdio.push('ipc');
       env.WATCH_REPORT_DEPENDENCIES = '1';

lib/internal/test_runner/utils.js

@@ -9,6 +9,7 @@ const {
   SafeMap,
   Symbol,
 } = primordials;
+
 const { basename } = require('path');
 const { createWriteStream } = require('fs');
 const { pathToFileURL } = require('internal/url');
@@ -172,25 +173,33 @@ function parseCommandLine() {
 
   const isTestRunner = getOptionValue('--test');
   const coverage = getOptionValue('--experimental-test-coverage');
-  const destinations = getOptionValue('--test-reporter-destination');
-  const reporters = getOptionValue('--test-reporter');
+  const isChildProcess = process.env.NODE_TEST_CONTEXT === 'child';
+  let destinations;
+  let reporters;
   let testNamePatterns;
   let testOnlyFlag;
 
-  if (reporters.length === 0 && destinations.length === 0) {
-    ArrayPrototypePush(reporters, kDefaultReporter);
-  }
+  if (isChildProcess) {
+    reporters = [kDefaultReporter];
+    destinations = [kDefaultDestination];
+  } else {
+    destinations = getOptionValue('--test-reporter-destination');
+    reporters = getOptionValue('--test-reporter');
+    if (reporters.length === 0 && destinations.length === 0) {
+      ArrayPrototypePush(reporters, kDefaultReporter);
+    }
 
-  if (reporters.length === 1 && destinations.length === 0) {
-    ArrayPrototypePush(destinations, kDefaultDestination);
-  }
+    if (reporters.length === 1 && destinations.length === 0) {
+      ArrayPrototypePush(destinations, kDefaultDestination);
+    }
 
-  if (destinations.length !== reporters.length) {
-    throw new ERR_INVALID_ARG_VALUE(
-      '--test-reporter',
-      reporters,
-      'must match the number of specified \'--test-reporter-destination\'',
-    );
+    if (destinations.length !== reporters.length) {
+      throw new ERR_INVALID_ARG_VALUE(
+        '--test-reporter',
+        reporters,
+        'must match the number of specified \'--test-reporter-destination\'',
+      );
+    }
   }
 
   if (isTestRunner) {

src/node_options.cc

@@ -590,10 +590,12 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
             &EnvironmentOptions::test_name_pattern);
   AddOption("--test-reporter",
             "report test output using the given reporter",
-            &EnvironmentOptions::test_reporter);
+            &EnvironmentOptions::test_reporter,
+            kAllowedInEnvvar);
   AddOption("--test-reporter-destination",
             "report given reporter to the given destination",
-            &EnvironmentOptions::test_reporter_destination);
+            &EnvironmentOptions::test_reporter_destination,
+            kAllowedInEnvvar);
   AddOption("--test-only",
             "run tests with 'only' option set",
             &EnvironmentOptions::test_only,