test: refactor test-dgram-address.js

- separate the IPv4 and IPv6 tests using block scopes
- use common.mustCall() and arrow functions for callbacks
- add coverage for case where address() throws

PR-URL: nodejs#11271
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-dgram-address.js

@@ -3,45 +3,58 @@ const common = require('../common');
 const assert = require('assert');
 const dgram = require('dgram');
 
-// IPv4 Test
-const socket_ipv4 = dgram.createSocket('udp4');
-const family_ipv4 = 'IPv4';
-
-socket_ipv4.on('listening', function() {
-  const address_ipv4 = socket_ipv4.address();
-  assert.strictEqual(address_ipv4.address, common.localhostIPv4);
-  assert.strictEqual(typeof address_ipv4.port, 'number');
-  assert.ok(isFinite(address_ipv4.port));
-  assert.ok(address_ipv4.port > 0);
-  assert.strictEqual(address_ipv4.family, family_ipv4);
-  socket_ipv4.close();
-});
-
-socket_ipv4.on('error', function(e) {
-  console.log('Error on udp4 socket. ' + e.toString());
-  socket_ipv4.close();
-});
-
-socket_ipv4.bind(0, common.localhostIPv4);
-
-// IPv6 Test
-const localhost_ipv6 = '::1';
-const socket_ipv6 = dgram.createSocket('udp6');
-const family_ipv6 = 'IPv6';
-
-socket_ipv6.on('listening', function() {
-  const address_ipv6 = socket_ipv6.address();
-  assert.strictEqual(address_ipv6.address, localhost_ipv6);
-  assert.strictEqual(typeof address_ipv6.port, 'number');
-  assert.ok(isFinite(address_ipv6.port));
-  assert.ok(address_ipv6.port > 0);
-  assert.strictEqual(address_ipv6.family, family_ipv6);
-  socket_ipv6.close();
-});
-
-socket_ipv6.on('error', function(e) {
-  console.log('Error on udp6 socket. ' + e.toString());
-  socket_ipv6.close();
-});
-
-socket_ipv6.bind(0, localhost_ipv6);
+{
+  // IPv4 Test
+  const socket = dgram.createSocket('udp4');
+
+  socket.on('listening', common.mustCall(() => {
+    const address = socket.address();
+
+    assert.strictEqual(address.address, common.localhostIPv4);
+    assert.strictEqual(typeof address.port, 'number');
+    assert.ok(isFinite(address.port));
+    assert.ok(address.port > 0);
+    assert.strictEqual(address.family, 'IPv4');
+    socket.close();
+  }));
+
+  socket.on('error', (err) => {
+    socket.close();
+    common.fail(`Unexpected error on udp4 socket. ${err.toString()}`);
+  });
+
+  socket.bind(0, common.localhostIPv4);
+}
+
+{
+  // IPv6 Test
+  const socket = dgram.createSocket('udp6');
+  const localhost = '::1';
+
+  socket.on('listening', common.mustCall(() => {
+    const address = socket.address();
+
+    assert.strictEqual(address.address, localhost);
+    assert.strictEqual(typeof address.port, 'number');
+    assert.ok(isFinite(address.port));
+    assert.ok(address.port > 0);
+    assert.strictEqual(address.family, 'IPv6');
+    socket.close();
+  }));
+
+  socket.on('error', (err) => {
+    socket.close();
+    common.fail(`Unexpected error on udp6 socket. ${err.toString()}`);
+  });
+
+  socket.bind(0, localhost);
+}
+
+{
+  // Verify that address() throws if the socket is not bound.
+  const socket = dgram.createSocket('udp4');
+
+  assert.throws(() => {
+    socket.address();
+  }, /^Error: getsockname EINVAL$/);
+}