tls, https: throw exception on missing key/cert

Throw an exception in the tls.Server constructor when the options object
doesn't contain either a PFX or a key/certificate combo.

Said change exposed a bug in simple/test-tls-junk-closes-server. Addressed.

Fixes #3941.

lib/tls.js

@@ -1058,6 +1058,10 @@ function Server(/* [options], listener */) {
   // Handle option defaults:
   this.setOptions(options);
 
+  if (!self.pfx && (!self.cert || !self.key)) {
+    throw new Error('Missing PFX or certificate + private key.');
+  }
+
   var sharedCreds = crypto.createCredentials({
     pfx: self.pfx,
     key: self.key,

test/simple/test-tls-junk-closes-server.js

@@ -34,7 +34,7 @@ var options = {
   cert: fs.readFileSync(common.fixturesDir + '/keys/agent2-cert.pem')
 };
 
-var server = tls.createServer(function(s) {
+var server = tls.createServer(options, function(s) {
   s.write('welcome!\n');
   s.pipe(s);
 });

test/simple/test-tls-server-missing-options.js

@@ -0,0 +1,38 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+if (!process.versions.openssl) {
+  console.error('Skipping because node compiled without OpenSSL.');
+  process.exit(0);
+}
+
+var common = require('../common');
+var assert = require('assert');
+var https = require('https');
+var tls = require('tls');
+
+assert.throws(function() {
+  tls.createServer({ /* empty */}).listen(0);
+}, /missing.+certificate/i);
+
+assert.throws(function() {
+  https.createServer({ /* empty */}).listen(0);
+}, /missing.+certificate/i);