From 060c85102ea02b27f92228515fb1827af2bf88f7 Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Mon, 18 Jul 2022 15:24:01 +0530
Subject: [PATCH 01/15] test_runner: introduces test_concurrency flag

adds the test_concurrency flag,
if set to true, runs all the tests in parallel

Fixes: https://github.com/nodejs/node/issues/43837
---
 doc/api/cli.md                   | 8 ++++++++
 lib/internal/test_runner/test.js | 1 -
 src/node_options.cc              | 3 +++
 src/node_options.h               | 1 +
 4 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/doc/api/cli.md b/doc/api/cli.md
index f0a2e70b8d7b66..499fdafe404c65 100644
--- a/doc/api/cli.md
+++ b/doc/api/cli.md
@@ -1116,6 +1116,14 @@ Starts the Node.js command line test runner. This flag cannot be combined with
 `--check`, `--eval`, `--interactive`, or the inspector. See the documentation
 on [running tests from the command line][] for more details.
 
+### `--test-concurrency`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+Configures the test runner to run sub tests in parallel.
+
 ### `--test-only`
 
 <!-- YAML
diff --git a/lib/internal/test_runner/test.js b/lib/internal/test_runner/test.js
index 0755c42750ac87..d4ab48a77587bb 100644
--- a/lib/internal/test_runner/test.js
+++ b/lib/internal/test_runner/test.js
@@ -48,7 +48,6 @@ const isTestRunner = getOptionValue('--test');
 const testOnlyFlag = !isTestRunner && getOptionValue('--test-only');
 // TODO(cjihrig): Use uv_available_parallelism() once it lands.
 const rootConcurrency = isTestRunner ? cpus().length : 1;
-
 const kShouldAbort = Symbol('kShouldAbort');
 
 
diff --git a/src/node_options.cc b/src/node_options.cc
index 7a41f9bc3b87f6..fafaad7ec1e8d5 100644
--- a/src/node_options.cc
+++ b/src/node_options.cc
@@ -529,6 +529,9 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
   AddOption("--test",
             "launch test runner on startup",
             &EnvironmentOptions::test_runner);
+  AddOption("--test-concurrency",
+            "tests defined within a file run in parallel",
+            &EnvironmentOptions::test_concurrency);
   AddOption("--test-only",
             "run tests with 'only' option set",
             &EnvironmentOptions::test_only,
diff --git a/src/node_options.h b/src/node_options.h
index 827c6298f5ea28..f2c9aa0f6a12b9 100644
--- a/src/node_options.h
+++ b/src/node_options.h
@@ -151,6 +151,7 @@ class EnvironmentOptions : public Options {
   std::string redirect_warnings;
   std::string diagnostic_dir;
   bool test_runner = false;
+  bool test_concurrency = false;
   bool test_only = false;
   bool test_udp_no_try_send = false;
   bool throw_deprecation = false;

From 7613bdde31bf11c668fc1d5d8e404462e011aa58 Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Mon, 18 Jul 2022 16:39:25 +0530
Subject: [PATCH 02/15] test_runner: use flag for root concurrency

---
 doc/api/cli.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/api/cli.md b/doc/api/cli.md
index 499fdafe404c65..59e6f66b7717dc 100644
--- a/doc/api/cli.md
+++ b/doc/api/cli.md
@@ -1122,7 +1122,7 @@ on [running tests from the command line][] for more details.
 added: REPLACEME
 -->
 
-Configures the test runner to run sub tests in parallel.
+Configures the test concurrently.
 
 ### `--test-only`
 

From 947d7ba225163fd0169fb8c32a77404ec27258fb Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Mon, 18 Jul 2022 16:41:40 +0530
Subject: [PATCH 03/15] test_runner: fix concurrently flag documentation

---
 doc/api/cli.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/api/cli.md b/doc/api/cli.md
index 59e6f66b7717dc..6ce9c991e5eafc 100644
--- a/doc/api/cli.md
+++ b/doc/api/cli.md
@@ -1122,7 +1122,7 @@ on [running tests from the command line][] for more details.
 added: REPLACEME
 -->
 
-Configures the test concurrently.
+Configures the tests to run concurrently.
 
 ### `--test-only`
 

From 0bd2eed00a14d0c91e7ae953862ab7a39a5a48ff Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Mon, 18 Jul 2022 19:01:13 +0530
Subject: [PATCH 04/15] test_runner: use exiting option instead of cli

---
 doc/api/cli.md                   |  8 --------
 lib/internal/test_runner/test.js | 10 +++++++++-
 src/node_options.cc              |  3 ---
 src/node_options.h               |  1 -
 4 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/doc/api/cli.md b/doc/api/cli.md
index 6ce9c991e5eafc..f0a2e70b8d7b66 100644
--- a/doc/api/cli.md
+++ b/doc/api/cli.md
@@ -1116,14 +1116,6 @@ Starts the Node.js command line test runner. This flag cannot be combined with
 `--check`, `--eval`, `--interactive`, or the inspector. See the documentation
 on [running tests from the command line][] for more details.
 
-### `--test-concurrency`
-
-<!-- YAML
-added: REPLACEME
--->
-
-Configures the tests to run concurrently.
-
 ### `--test-only`
 
 <!-- YAML
diff --git a/lib/internal/test_runner/test.js b/lib/internal/test_runner/test.js
index d4ab48a77587bb..3c007ccd861325 100644
--- a/lib/internal/test_runner/test.js
+++ b/lib/internal/test_runner/test.js
@@ -47,7 +47,7 @@ const noop = FunctionPrototype;
 const isTestRunner = getOptionValue('--test');
 const testOnlyFlag = !isTestRunner && getOptionValue('--test-only');
 // TODO(cjihrig): Use uv_available_parallelism() once it lands.
-const rootConcurrency = isTestRunner ? cpus().length : 1;
+const rootConcurrency = isTestRunner ? MathMax(cpus().length - 1, 1) : 1;
 const kShouldAbort = Symbol('kShouldAbort');
 
 
@@ -147,6 +147,14 @@ class Test extends AsyncResource {
       this.concurrency = concurrency;
     }
 
+    if (typeof concurrency === 'boolean') {
+      if (isTestRunner) {
+        this.concurrency = concurrency ? MathMax(cpus().length - 1, 1) : 1;
+      } else {
+        this.concurrency = concurrency ? Infinity : 1;
+      }
+    }
+
     if (isUint32(timeout)) {
       this.timeout = timeout;
     }
diff --git a/src/node_options.cc b/src/node_options.cc
index fafaad7ec1e8d5..7a41f9bc3b87f6 100644
--- a/src/node_options.cc
+++ b/src/node_options.cc
@@ -529,9 +529,6 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
   AddOption("--test",
             "launch test runner on startup",
             &EnvironmentOptions::test_runner);
-  AddOption("--test-concurrency",
-            "tests defined within a file run in parallel",
-            &EnvironmentOptions::test_concurrency);
   AddOption("--test-only",
             "run tests with 'only' option set",
             &EnvironmentOptions::test_only,
diff --git a/src/node_options.h b/src/node_options.h
index f2c9aa0f6a12b9..827c6298f5ea28 100644
--- a/src/node_options.h
+++ b/src/node_options.h
@@ -151,7 +151,6 @@ class EnvironmentOptions : public Options {
   std::string redirect_warnings;
   std::string diagnostic_dir;
   bool test_runner = false;
-  bool test_concurrency = false;
   bool test_only = false;
   bool test_udp_no_try_send = false;
   bool throw_deprecation = false;

From ca04bb6efb4fa02a0c5bc33bf3b99f735d3d703d Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Mon, 18 Jul 2022 21:13:16 +0530
Subject: [PATCH 05/15] test_runner: add test cases for concurrency

---
 test/message/test_runner_describe_it.js | 44 +++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/test/message/test_runner_describe_it.js b/test/message/test_runner_describe_it.js
index c272fb38a749f6..692ea97f379796 100644
--- a/test/message/test_runner_describe_it.js
+++ b/test/message/test_runner_describe_it.js
@@ -339,3 +339,47 @@ describe('timeouts', () => {
     setTimeout(done, 10);
   });
 });
+
+describe('Concurrency option (boolean) = true ', { concurrency: true }, () => {
+  const suiteStartDateTime = new Date().getTime();
+  const extraBufferTime = 10;
+  it('should be over by 3 seconds from suite start', async () => {
+    const duration = 3000;
+    const expectedEndDateTime = suiteStartDateTime + duration + extraBufferTime;
+    await new Promise((resolve, reject) => {
+      setTimeout(resolve, duration)
+    });
+    assert.strictEqual( expectedEndDateTime > new Date().getTime(), true)
+  });
+  it('should be over by 1 second from suite start', async () => {
+      const duration = 1000;
+      const expectedEndDateTime = suiteStartDateTime + duration + extraBufferTime;
+      await new Promise((resolve, reject) => {
+        setTimeout(resolve, duration)
+      });
+      assert.strictEqual( expectedEndDateTime > new Date().getTime(), true)
+    });
+});
+
+describe('Concurrency option (boolean) = false ', { concurrency: false }, () => {
+  const suiteStartDateTime = new Date().getTime();
+  const extraBufferTime = 10;
+  it('should be over by 3 seconds from suite start', async () => {
+    const duration = 3000;
+    const expectedEndDateTime = suiteStartDateTime + duration + extraBufferTime;
+    await new Promise((resolve, reject) => {
+      setTimeout(resolve, duration)
+    });
+    assert.strictEqual( expectedEndDateTime > new Date().getTime(), true)
+  });
+  it('should be over by 4 seconds from suite start', async () => {
+      const duration = 1000;
+      const prevTestDuration = 3000;
+      const expectedEndDateTime = 
+      suiteStartDateTime + duration + extraBufferTime + prevTestDuration;
+      await new Promise((resolve, reject) => {
+        setTimeout(resolve, duration)
+      });
+      assert.strictEqual( expectedEndDateTime > new Date().getTime(), true)
+    });
+});
\ No newline at end of file

From b7bf594349d3ffca1e41c46b64aa6baad148537d Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Mon, 18 Jul 2022 21:13:36 +0530
Subject: [PATCH 06/15] test_runner: imports in alphabetical order

---
 lib/internal/test_runner/test.js | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/internal/test_runner/test.js b/lib/internal/test_runner/test.js
index 3c007ccd861325..239a1f49f80d0f 100644
--- a/lib/internal/test_runner/test.js
+++ b/lib/internal/test_runner/test.js
@@ -4,6 +4,7 @@ const {
   ArrayPrototypeShift,
   ArrayPrototypeUnshift,
   FunctionPrototype,
+  MathMax,
   Number,
   PromisePrototypeThen,
   PromiseResolve,
@@ -145,9 +146,7 @@ class Test extends AsyncResource {
 
     if (isUint32(concurrency) && concurrency !== 0) {
       this.concurrency = concurrency;
-    }
-
-    if (typeof concurrency === 'boolean') {
+    } else if (typeof concurrency === 'boolean') {
       if (isTestRunner) {
         this.concurrency = concurrency ? MathMax(cpus().length - 1, 1) : 1;
       } else {

From cc867b4da40555d02bec98976f41c3caf5dbdb44 Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Mon, 18 Jul 2022 21:16:57 +0530
Subject: [PATCH 07/15] test_runner: fix linting in tests

---
 test/message/test_runner_describe_it.js | 36 ++++++++++++-------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/test/message/test_runner_describe_it.js b/test/message/test_runner_describe_it.js
index 692ea97f379796..71277e2b3200d8 100644
--- a/test/message/test_runner_describe_it.js
+++ b/test/message/test_runner_describe_it.js
@@ -347,18 +347,18 @@ describe('Concurrency option (boolean) = true ', { concurrency: true }, () => {
     const duration = 3000;
     const expectedEndDateTime = suiteStartDateTime + duration + extraBufferTime;
     await new Promise((resolve, reject) => {
-      setTimeout(resolve, duration)
+      setTimeout(resolve, duration);
     });
-    assert.strictEqual( expectedEndDateTime > new Date().getTime(), true)
+    assert.strictEqual(expectedEndDateTime > new Date().getTime(), true);
   });
   it('should be over by 1 second from suite start', async () => {
-      const duration = 1000;
-      const expectedEndDateTime = suiteStartDateTime + duration + extraBufferTime;
-      await new Promise((resolve, reject) => {
-        setTimeout(resolve, duration)
-      });
-      assert.strictEqual( expectedEndDateTime > new Date().getTime(), true)
+    const duration = 1000;
+    const expectedEndDateTime = suiteStartDateTime + duration + extraBufferTime;
+    await new Promise((resolve, reject) => {
+      setTimeout(resolve, duration);
     });
+    assert.strictEqual(expectedEndDateTime > new Date().getTime(), true);
+  });
 });
 
 describe('Concurrency option (boolean) = false ', { concurrency: false }, () => {
@@ -368,18 +368,18 @@ describe('Concurrency option (boolean) = false ', { concurrency: false }, () =>
     const duration = 3000;
     const expectedEndDateTime = suiteStartDateTime + duration + extraBufferTime;
     await new Promise((resolve, reject) => {
-      setTimeout(resolve, duration)
+      setTimeout(resolve, duration);
     });
-    assert.strictEqual( expectedEndDateTime > new Date().getTime(), true)
+    assert.strictEqual(expectedEndDateTime > new Date().getTime(), true);
   });
   it('should be over by 4 seconds from suite start', async () => {
-      const duration = 1000;
-      const prevTestDuration = 3000;
-      const expectedEndDateTime = 
+    const duration = 1000;
+    const prevTestDuration = 3000;
+    const expectedEndDateTime =
       suiteStartDateTime + duration + extraBufferTime + prevTestDuration;
-      await new Promise((resolve, reject) => {
-        setTimeout(resolve, duration)
-      });
-      assert.strictEqual( expectedEndDateTime > new Date().getTime(), true)
+    await new Promise((resolve, reject) => {
+      setTimeout(resolve, duration);
     });
-});
\ No newline at end of file
+    assert.strictEqual(expectedEndDateTime > new Date().getTime(), true);
+  });
+});

From f44d1b450860207306725ccc396db7a035802db5 Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Mon, 18 Jul 2022 21:30:42 +0530
Subject: [PATCH 08/15] doc: update for concurrency option in test

---
 doc/api/test.md | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/doc/api/test.md b/doc/api/test.md
index 2708324b1dc253..3979b9146b605c 100644
--- a/doc/api/test.md
+++ b/doc/api/test.md
@@ -331,7 +331,12 @@ changes:
   does not have a name.
 * `options` {Object} Configuration options for the test. The following
   properties are supported:
-  * `concurrency` {number} The number of tests that can be run at the same time.
+  * `concurrency` {number|boolean} If a number is provided,
+  then that many tests would run in parallel.
+    If truthy, on top level, it would run (number of cpu cores - 1)
+    tests in parallel.
+    For subtests, it will be infinity tests in parallel.
+    If falsy, on top level & subtest level it would only run one test at a time.
     If unspecified, subtests inherit this value from their parent.
     **Default:** `1`.
   * `only` {boolean} If truthy, and the test context is configured to run

From 3834d49621150207a30edfe45f8a496c9cad83ae Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Mon, 18 Jul 2022 21:32:21 +0530
Subject: [PATCH 09/15] doc: format test

---
 doc/api/test.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/api/test.md b/doc/api/test.md
index 3979b9146b605c..ab0312c65a476c 100644
--- a/doc/api/test.md
+++ b/doc/api/test.md
@@ -332,7 +332,7 @@ changes:
 * `options` {Object} Configuration options for the test. The following
   properties are supported:
   * `concurrency` {number|boolean} If a number is provided,
-  then that many tests would run in parallel.
+    then that many tests would run in parallel.
     If truthy, on top level, it would run (number of cpu cores - 1)
     tests in parallel.
     For subtests, it will be infinity tests in parallel.

From 8634f8ab4b45617399b4537e985f0d2ba0398e4a Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Tue, 19 Jul 2022 21:39:53 +0530
Subject: [PATCH 10/15] test_runner: update test + update docs

---
 doc/api/test.md                          |  7 ++--
 test/message/test_runner_describe_it.js  | 44 ------------------------
 test/parallel/test-runner-concurrency.js | 28 +++++++++++++++
 3 files changed, 32 insertions(+), 47 deletions(-)
 create mode 100644 test/parallel/test-runner-concurrency.js

diff --git a/doc/api/test.md b/doc/api/test.md
index ab0312c65a476c..13d05a2dd3c32f 100644
--- a/doc/api/test.md
+++ b/doc/api/test.md
@@ -333,10 +333,11 @@ changes:
   properties are supported:
   * `concurrency` {number|boolean} If a number is provided,
     then that many tests would run in parallel.
-    If truthy, on top level, it would run (number of cpu cores - 1)
-    tests in parallel.
+    If truthy, when running in `--test` mode, it would run
+    (number of cpu cores - 1) tests in parallel.
     For subtests, it will be infinity tests in parallel.
-    If falsy, on top level & subtest level it would only run one test at a time.
+    If falsy, when running in `--test` mode & subtest level
+    it would only run one test at a time.
     If unspecified, subtests inherit this value from their parent.
     **Default:** `1`.
   * `only` {boolean} If truthy, and the test context is configured to run
diff --git a/test/message/test_runner_describe_it.js b/test/message/test_runner_describe_it.js
index 71277e2b3200d8..c272fb38a749f6 100644
--- a/test/message/test_runner_describe_it.js
+++ b/test/message/test_runner_describe_it.js
@@ -339,47 +339,3 @@ describe('timeouts', () => {
     setTimeout(done, 10);
   });
 });
-
-describe('Concurrency option (boolean) = true ', { concurrency: true }, () => {
-  const suiteStartDateTime = new Date().getTime();
-  const extraBufferTime = 10;
-  it('should be over by 3 seconds from suite start', async () => {
-    const duration = 3000;
-    const expectedEndDateTime = suiteStartDateTime + duration + extraBufferTime;
-    await new Promise((resolve, reject) => {
-      setTimeout(resolve, duration);
-    });
-    assert.strictEqual(expectedEndDateTime > new Date().getTime(), true);
-  });
-  it('should be over by 1 second from suite start', async () => {
-    const duration = 1000;
-    const expectedEndDateTime = suiteStartDateTime + duration + extraBufferTime;
-    await new Promise((resolve, reject) => {
-      setTimeout(resolve, duration);
-    });
-    assert.strictEqual(expectedEndDateTime > new Date().getTime(), true);
-  });
-});
-
-describe('Concurrency option (boolean) = false ', { concurrency: false }, () => {
-  const suiteStartDateTime = new Date().getTime();
-  const extraBufferTime = 10;
-  it('should be over by 3 seconds from suite start', async () => {
-    const duration = 3000;
-    const expectedEndDateTime = suiteStartDateTime + duration + extraBufferTime;
-    await new Promise((resolve, reject) => {
-      setTimeout(resolve, duration);
-    });
-    assert.strictEqual(expectedEndDateTime > new Date().getTime(), true);
-  });
-  it('should be over by 4 seconds from suite start', async () => {
-    const duration = 1000;
-    const prevTestDuration = 3000;
-    const expectedEndDateTime =
-      suiteStartDateTime + duration + extraBufferTime + prevTestDuration;
-    await new Promise((resolve, reject) => {
-      setTimeout(resolve, duration);
-    });
-    assert.strictEqual(expectedEndDateTime > new Date().getTime(), true);
-  });
-});
diff --git a/test/parallel/test-runner-concurrency.js b/test/parallel/test-runner-concurrency.js
new file mode 100644
index 00000000000000..8d18cee47c9063
--- /dev/null
+++ b/test/parallel/test-runner-concurrency.js
@@ -0,0 +1,28 @@
+'use strict';
+require('../common');
+const { describe, it } = require('node:test');
+const assert = require('assert');
+
+describe('Concurrency option (boolean) = true ', { concurrency: true }, () => {
+  let isFirstTestOver = false;
+  it('should end after 1000ms', () => new Promise((resolve) => {
+    setTimeout(() => { resolve(); isFirstTestOver = true; }, 1000);
+  }));
+  it('should start before the previous test ends', () => {
+    assert.strictEqual(isFirstTestOver, false);
+  });
+});
+
+describe(
+  'Concurrency option (boolean) = false ',
+  { concurrency: false },
+  () => {
+    let isFirstTestOver = false;
+    it('should end after 1000ms', () => new Promise((resolve) => {
+      setTimeout(() => { resolve(); isFirstTestOver = true; }, 1000);
+    }));
+    it('should start after the previous test ends', () => {
+      assert.strictEqual(isFirstTestOver, true);
+    });
+  }
+);

From 28b7d0ee239a57bb1e5254c8dcbd0897b3d424d4 Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Tue, 19 Jul 2022 23:48:30 +0530
Subject: [PATCH 11/15] test_runner: update test support less than 2 core

---
 test/parallel/test-runner-concurrency.js | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/test/parallel/test-runner-concurrency.js b/test/parallel/test-runner-concurrency.js
index 8d18cee47c9063..12479f6e6142fd 100644
--- a/test/parallel/test-runner-concurrency.js
+++ b/test/parallel/test-runner-concurrency.js
@@ -2,6 +2,7 @@
 require('../common');
 const { describe, it } = require('node:test');
 const assert = require('assert');
+const { cpus } = require('os');
 
 describe('Concurrency option (boolean) = true ', { concurrency: true }, () => {
   let isFirstTestOver = false;
@@ -9,7 +10,12 @@ describe('Concurrency option (boolean) = true ', { concurrency: true }, () => {
     setTimeout(() => { resolve(); isFirstTestOver = true; }, 1000);
   }));
   it('should start before the previous test ends', () => {
-    assert.strictEqual(isFirstTestOver, false);
+    // On dual & single core machines, the concurrency is set to 1 if a truthy value is passed
+    if (cpus().length <= 2) {
+      assert.strictEqual(isFirstTestOver, true);
+    } else {
+      assert.strictEqual(isFirstTestOver, false);
+    }
   });
 });
 
@@ -26,3 +32,17 @@ describe(
     });
   }
 );
+
+describe('default concurrency (1)', () => {
+  let isFirstTestOver = false;
+  it('should end after 1000ms', () =>
+    new Promise((resolve) => {
+      setTimeout(() => {
+        resolve();
+        isFirstTestOver = true;
+      }, 1000);
+    }));
+  it('should start after the previous test ends', () => {
+    assert.strictEqual(isFirstTestOver, true);
+  });
+});

From d1a0b790eebb33fdfbd531ffd16bddf5e299c884 Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Wed, 20 Jul 2022 20:24:04 +0530
Subject: [PATCH 12/15] Revert "test_runner: update test support less than 2
 core"

This reverts commit 5fdcfd0ea643e41ff2f0d55e20727bc4ff7c7b5e.
---
 test/parallel/test-runner-concurrency.js | 22 +---------------------
 1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/test/parallel/test-runner-concurrency.js b/test/parallel/test-runner-concurrency.js
index 12479f6e6142fd..8d18cee47c9063 100644
--- a/test/parallel/test-runner-concurrency.js
+++ b/test/parallel/test-runner-concurrency.js
@@ -2,7 +2,6 @@
 require('../common');
 const { describe, it } = require('node:test');
 const assert = require('assert');
-const { cpus } = require('os');
 
 describe('Concurrency option (boolean) = true ', { concurrency: true }, () => {
   let isFirstTestOver = false;
@@ -10,12 +9,7 @@ describe('Concurrency option (boolean) = true ', { concurrency: true }, () => {
     setTimeout(() => { resolve(); isFirstTestOver = true; }, 1000);
   }));
   it('should start before the previous test ends', () => {
-    // On dual & single core machines, the concurrency is set to 1 if a truthy value is passed
-    if (cpus().length <= 2) {
-      assert.strictEqual(isFirstTestOver, true);
-    } else {
-      assert.strictEqual(isFirstTestOver, false);
-    }
+    assert.strictEqual(isFirstTestOver, false);
   });
 });
 
@@ -32,17 +26,3 @@ describe(
     });
   }
 );
-
-describe('default concurrency (1)', () => {
-  let isFirstTestOver = false;
-  it('should end after 1000ms', () =>
-    new Promise((resolve) => {
-      setTimeout(() => {
-        resolve();
-        isFirstTestOver = true;
-      }, 1000);
-    }));
-  it('should start after the previous test ends', () => {
-    assert.strictEqual(isFirstTestOver, true);
-  });
-});

From 58d8fdfdae577e6520ac82bddc79ff7e846eb024 Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Wed, 20 Jul 2022 20:26:49 +0530
Subject: [PATCH 13/15] doc: update concurrency in test

---
 doc/api/test.md | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/doc/api/test.md b/doc/api/test.md
index 13d05a2dd3c32f..c7a042b5efe19c 100644
--- a/doc/api/test.md
+++ b/doc/api/test.md
@@ -333,13 +333,12 @@ changes:
   properties are supported:
   * `concurrency` {number|boolean} If a number is provided,
     then that many tests would run in parallel.
-    If truthy, when running in `--test` mode, it would run
-    (number of cpu cores - 1) tests in parallel.
-    For subtests, it will be infinity tests in parallel.
-    If falsy, when running in `--test` mode & subtest level
-    it would only run one test at a time.
+    If truthy, it would run (number of cpu cores - 1)
+    tests in parallel.
+    For subtests, it will be `Infinity` tests in parallel.
+    If falsy, it would only run one test at a time.
     If unspecified, subtests inherit this value from their parent.
-    **Default:** `1`.
+    **Default:** `false`.
   * `only` {boolean} If truthy, and the test context is configured to run
     `only` tests, then this test will be run. Otherwise, the test is skipped.
     **Default:** `false`.

From 8cc4c10ffd25c8bf4e49a7426a59c71f7d577675 Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Wed, 20 Jul 2022 20:28:23 +0530
Subject: [PATCH 14/15] test_runner: add comment in test case

---
 test/parallel/test-runner-concurrency.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test/parallel/test-runner-concurrency.js b/test/parallel/test-runner-concurrency.js
index 8d18cee47c9063..05c33e92de93bc 100644
--- a/test/parallel/test-runner-concurrency.js
+++ b/test/parallel/test-runner-concurrency.js
@@ -9,6 +9,7 @@ describe('Concurrency option (boolean) = true ', { concurrency: true }, () => {
     setTimeout(() => { resolve(); isFirstTestOver = true; }, 1000);
   }));
   it('should start before the previous test ends', () => {
+    // Should work even on single core CPUs
     assert.strictEqual(isFirstTestOver, false);
   });
 });

From 03c1313f6d8929a3ca79340f1aa165a96735135c Mon Sep 17 00:00:00 2001
From: Lenvin Gonsalves <lenvingonsalves@gmail.com>
Date: Sun, 24 Jul 2022 03:29:31 +0530
Subject: [PATCH 15/15] test_runner: apply suggestions

---
 lib/internal/test_runner/test.js         | 6 +++---
 test/parallel/test-runner-concurrency.js | 8 ++++----
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/lib/internal/test_runner/test.js b/lib/internal/test_runner/test.js
index 239a1f49f80d0f..af7fec1dfdb8fb 100644
--- a/lib/internal/test_runner/test.js
+++ b/lib/internal/test_runner/test.js
@@ -147,10 +147,10 @@ class Test extends AsyncResource {
     if (isUint32(concurrency) && concurrency !== 0) {
       this.concurrency = concurrency;
     } else if (typeof concurrency === 'boolean') {
-      if (isTestRunner) {
-        this.concurrency = concurrency ? MathMax(cpus().length - 1, 1) : 1;
+      if (concurrency) {
+        this.concurrency = isTestRunner ? MathMax(cpus().length - 1, 1) : Infinity;
       } else {
-        this.concurrency = concurrency ? Infinity : 1;
+        this.concurrency = 1;
       }
     }
 
diff --git a/test/parallel/test-runner-concurrency.js b/test/parallel/test-runner-concurrency.js
index 05c33e92de93bc..802cff3e9be375 100644
--- a/test/parallel/test-runner-concurrency.js
+++ b/test/parallel/test-runner-concurrency.js
@@ -5,8 +5,8 @@ const assert = require('assert');
 
 describe('Concurrency option (boolean) = true ', { concurrency: true }, () => {
   let isFirstTestOver = false;
-  it('should end after 1000ms', () => new Promise((resolve) => {
-    setTimeout(() => { resolve(); isFirstTestOver = true; }, 1000);
+  it('should start the first test', () => new Promise((resolve) => {
+    setImmediate(() => { isFirstTestOver = true; resolve(); });
   }));
   it('should start before the previous test ends', () => {
     // Should work even on single core CPUs
@@ -19,8 +19,8 @@ describe(
   { concurrency: false },
   () => {
     let isFirstTestOver = false;
-    it('should end after 1000ms', () => new Promise((resolve) => {
-      setTimeout(() => { resolve(); isFirstTestOver = true; }, 1000);
+    it('should start the first test', () => new Promise((resolve) => {
+      setImmediate(() => { isFirstTestOver = true; resolve(); });
     }));
     it('should start after the previous test ends', () => {
       assert.strictEqual(isFirstTestOver, true);