test: add regression test for 13557

Fixes: #13557
PR-URL: #13560
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: addaleax

test/parallel/test-readline-reopen.js

@@ -0,0 +1,44 @@
+'use strict';
+
+// Regression test for https://github.com/nodejs/node/issues/13557
+// Tests that multiple subsequent readline instances can re-use an input stream.
+
+constcommon=require('../common');
+constassert=require('assert');
+constreadline=require('readline');
+const{ PassThrough }=require('stream');
+
+constinput=newPassThrough();
+constoutput=newPassThrough();
+
+constrl1=readline.createInterface({
+ input,
+ output,
+terminal: true
+});
+
+rl1.on('line',common.mustCall(rl1OnLine));
+
+// Write a line plus the first byte of a UTF-8 multibyte character to make sure
+// that it doesn’t get lost when closing the readline instance.
+input.write(Buffer.concat([
+Buffer.from('foo\n'),
+Buffer.from([0xe2])// Exactly one third of a ☃ snowman.
+]));
+
+functionrl1OnLine(line){
+assert.strictEqual(line,'foo');
+rl1.close();
+constrl2=readline.createInterface({
+ input,
+ output,
+terminal: true
+});
+
+rl2.on('line',common.mustCall((line)=>{
+assert.strictEqual(line,'☃bar');
+rl2.close();
+}));
+input.write(Buffer.from([0x98,0x83]));// The rest of the ☃ snowman.
+input.write('bar\n');
+}