test: add common.noop, default for common.mustCall()

Export a new common.noop no-operation function for general use.
Allow using common.mustCall() without a fn argument to simplify
test cases.

Replace various non-op functions throughout tests with common.noop

PR-URL: https://github.com/nodejs/node/pull/12027
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Teddy Katz <teddy.katz@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/test/parallel/test-stream-duplex.js b/test/parallel/test-stream-duplex.js
index 9702eb9fda..5a686a6aba 100644
--- a/test/parallel/test-stream-duplex.js
+++ b/test/parallel/test-stream-duplex.js
@@ -18,9 +18,9 @@
 // DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
-
 'use strict';
-require('../common');
+
+const common = require('../common');
 const assert = require('assert');
 const Duplex = require('stream').Transform;
 
@@ -38,7 +38,7 @@ stream._write = (obj, _, cb) => {
   cb();
 };
 
-stream._read = () => {};
+stream._read = common.noop;
 
 stream.on('data', (obj) => {
   read = obj;