test: refactor test-tls-connect-simple

refactor var -> const/let
refactor process.on('exit') into common.mustCall

PR-URL: https://github.com/nodejs/node/pull/9934
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-tls-connect-simple.js

@@ -1,58 +1,43 @@
 'use strict';
-var common = require('../common');
-var assert = require('assert');
+const common = require('../common');
 
 if (!common.hasCrypto) {
   common.skip('missing crypto');
   return;
 }
-var tls = require('tls');
+const tls = require('tls');
 
-var fs = require('fs');
+const fs = require('fs');
 
-var clientConnected = 0;
-var serverConnected = 0;
-var serverCloseCallbacks = 0;
-var serverCloseEvents = 0;
+let serverConnected = 0;
 
-var options = {
+const options = {
   key: fs.readFileSync(common.fixturesDir + '/keys/agent1-key.pem'),
   cert: fs.readFileSync(common.fixturesDir + '/keys/agent1-cert.pem')
 };
 
-var server = tls.Server(options, function(socket) {
+const server = tls.Server(options, common.mustCall(function(socket) {
   if (++serverConnected === 2) {
-    server.close(function() {
-      ++serverCloseCallbacks;
-    });
-    server.on('close', function() {
-      ++serverCloseEvents;
-    });
+    server.close(common.mustCall(function() {}));
+    server.on('close', common.mustCall(function() {}));
   }
-});
+}, 2));
 
 server.listen(0, function() {
-  var client1 = tls.connect({
+  const client1options = {
     port: this.address().port,
     rejectUnauthorized: false
-  }, function() {
-    ++clientConnected;
+  };
+  const client1 = tls.connect(client1options, common.mustCall(function() {
     client1.end();
-  });
+  }));
 
-  var client2 = tls.connect({
+  const client2options = {
     port: this.address().port,
     rejectUnauthorized: false
-  });
-  client2.on('secureConnect', function() {
-    ++clientConnected;
+  };
+  const client2 = tls.connect(client2options);
+  client2.on('secureConnect', common.mustCall(function() {
     client2.end();
-  });
-});
-
-process.on('exit', function() {
-  assert.equal(clientConnected, 2);
-  assert.equal(serverConnected, 2);
-  assert.equal(serverCloseCallbacks, 1);
-  assert.equal(serverCloseEvents, 1);
+  }));
 });