test: refactor common.ddCommand()

* Remove different paths for Windows and POSIX.
* Remove fixtures file. Simply run the command immediately/directly.
* Since it is never called with more than one value for kilobytes,
  eliminate that argument.
* Update/simplify tests that use this function. (They no longer need to
  use child_process to run the command.)
* Update documentation.

PR-URL: https://github.com/nodejs/node/pull/23411
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: George Adams <george.adams@uk.ibm.com>

1 files changed, 4 insertions, 8 deletions

diff --git a/test/common/index.js b/test/common/index.js
index 75fe2e1548..492bb2f357 100644
--- a/test/common/index.js
+++ b/test/common/index.js
@@ -28,7 +28,6 @@ const assert = require('assert');
 const os = require('os');
 const { exec, execSync, spawnSync } = require('child_process');
 const util = require('util');
-const { fixturesDir } = require('./fixtures');
 const tmpdir = require('./tmpdir');
 const {
   bits,
@@ -174,13 +173,10 @@ function childShouldThrowAndAbort() {
   });
 }
 
-function ddCommand(filename, kilobytes) {
-  if (isWindows) {
-    const p = path.resolve(fixturesDir, 'create-file.js');
-    return `"${process.argv[0]}" "${p}" "${filename}" ${kilobytes * 1024}`;
-  } else {
-    return `dd if=/dev/zero of="${filename}" bs=1024 count=${kilobytes}`;
-  }
+function ddCommand(filename) {
+  const fd = fs.openSync(filename, 'w');
+  fs.ftruncateSync(fd, 10 * 1024 * 1024);
+  fs.closeSync(fd);
 }