test: add coverage for socket write after close

This commit adds test coverage for the scenario where a socket's
handle has been closed prior to writing.

PR-URL: https://github.com/nodejs/node/pull/13171
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>

test/parallel/test-net-socket-write-after-close.js

@@ -0,0 +1,39 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const net = require('net');
+
+{
+  const server = net.createServer();
+
+  server.listen(common.mustCall(() => {
+    const port = server.address().port;
+    const client = net.connect({port}, common.mustCall(() => {
+      client.on('error', common.mustCall((err) => {
+        server.close();
+        assert.strictEqual(err.constructor, Error);
+        assert.strictEqual(err.message, 'write EBADF');
+      }));
+      client._handle.close();
+      client.write('foo');
+    }));
+  }));
+}
+
+{
+  const server = net.createServer();
+
+  server.listen(common.mustCall(() => {
+    const port = server.address().port;
+    const client = net.connect({port}, common.mustCall(() => {
+      client.on('error', common.mustCall((err) => {
+        server.close();
+        assert.strictEqual(err.constructor, Error);
+        assert.strictEqual(err.message, 'This socket is closed');
+      }));
+      client._handle.close();
+      client._handle = null;
+      client.write('foo');
+    }));
+  }));
+}