test: improve coverage of lib/readline.js

PR-URL: https://github.com/nodejs/node/pull/38646
Refs: https://coverage.nodejs.org/coverage-16e00a15deafdad0/lib/readline.js.html#L441
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>
Reviewed-By: Zijian Liu <lxxyxzj@gmail.com>
Reviewed-By: Mohammed Keyvanzadeh <mohammadkeyvanzade94@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

test/parallel/test-readline-interface.js

@@ -1061,6 +1061,16 @@ for (let i = 0; i < 12; i++) {
     rli.close();
   }
 
+  // Calling only the first question callback
+  {
+    const [rli] = getInterface({ terminal });
+    rli.question('foo?', common.mustCall((answer) => {
+      assert.strictEqual(answer, 'bar');
+    }));
+    rli.question('hello?', common.mustNotCall());
+    rli.write('bar\n');
+  }
+
   // Calling the question multiple times
   {
     const [rli] = getInterface({ terminal });
@@ -1329,6 +1339,26 @@ for (let i = 0; i < 12; i++) {
       rli.close();
     }), delay);
   }
+
+  // Write correctly if paused
+  {
+    const [rli] = getInterface({ terminal });
+    rli.on('line', common.mustCall((line) => {
+      assert.strictEqual(line, 'bar');
+    }));
+    rli.pause();
+    rli.write('bar\n');
+    assert.strictEqual(rli.paused, false);
+    rli.close();
+  }
+
+  // Write undefined
+  {
+    const [rli] = getInterface({ terminal });
+    rli.on('line', common.mustNotCall());
+    rli.write();
+    rli.close();
+  }
 });
 
 // Ensure that the _wordLeft method works even for large input