test: move common.onGC to individual module

Incrementally making `require('../common')` less of a monolith.
Move the `common.onGC()` utility to a separate standalone module
that is only imported when it's actually needed.

PR-URL: https://github.com/nodejs/node/pull/22446
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Weijia Wang <starkwang@126.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

1 files changed, 28 insertions, 15 deletions

diff --git a/test/common/README.md b/test/common/README.md
index 487c252af3..63d3b16361 100644
--- a/test/common/README.md
+++ b/test/common/README.md
@@ -296,21 +296,6 @@ otherwise.
 ### noWarnCode
 See `common.expectWarning()` for usage.
 
-### onGC(target, listener)
-* `target` [<Object>]
-* `listener` [<Object>]
-  * `ongc` [<Function>]
-
-Installs a GC listener for the collection of `target`.
-
-This uses `async_hooks` for GC tracking. This means that it enables
-`async_hooks` tracking, which may affect the test functionality. It also
-means that between a `global.gc()` call and the listener being invoked
-a full `setImmediate()` invocation passes.
-
-`listener` is an object to make it easier to use a closure; the target object
-should not be in scope when `listener.ongc()` is created.
-
 ### opensslCli
 * [<boolean>]
 
@@ -759,6 +744,34 @@ via `NODE_TEST_*` environment variables. For example, to configure
 `internet.addresses.INET_HOST`, set the environment
 variable `NODE_TEST_INET_HOST` to a specified host.
 
+## ongc Module
+
+The `ongc` module allows a garbage collection listener to be installed. The
+module exports a single `onGC()` function.
+
+```js
+require('../common');
+const onGC = require('../common/ongc');
+
+onGC({}, { ongc() { console.log('collected'); } });
+```
+
+### onGC(target, listener)
+* `target` [<Object>]
+* `listener` [<Object>]
+  * `ongc` [<Function>]
+
+Installs a GC listener for the collection of `target`.
+
+This uses `async_hooks` for GC tracking. This means that it enables
+`async_hooks` tracking, which may affect the test functionality. It also
+means that between a `global.gc()` call and the listener being invoked
+a full `setImmediate()` invocation passes.
+
+`listener` is an object to make it easier to use a closure; the target object
+should not be in scope when `listener.ongc()` is created.
+
+
 ## tmpdir Module
 
 The `tmpdir` module supports the use of a temporary directory for testing.