fix(uri_parser): support a default database on mongodb+srv uris

NODE-1321

Author: mbroadst

lib/uri_parser.js

@@ -71,9 +71,19 @@ function parseSrvConnectionString(uri, options, callback) {
         i === 0 ? `${base}${address.name}:${address.port}` : `${address.name}:${address.port}`
     );
 
-    let connectionString = connectionStrings.join(',') + '/';
+    let connectionString = `${connectionStrings.join(',')}/`;
     let connectionStringOptions = [];
 
+    // Add the default database if needed
+    if (result.path) {
+      let defaultDb = result.path.slice(1);
+      if (defaultDb.indexOf('?') !== -1) {
+        defaultDb = defaultDb.slice(0, defaultDb.indexOf('?'));
+      }
+
+      connectionString += defaultDb;
+    }
+
     // Default to SSL true
     if (!options.ssl && (!result.search || result.query['ssl'] == null)) {
       connectionStringOptions.push('ssl=true');

test/tests/unit/mongodb_srv_spec_tests.js

@@ -5,6 +5,13 @@ const parseConnectionString = require('../../../lib/uri_parser');
 const expect = require('chai').expect;
 
 describe('mongodb+srv (spec)', function() {
+  it('should parse a default database', function(done) {
+    parseConnectionString('mongodb+srv://test5.test.build.10gen.cc/somedb', (err, result) => {
+      expect(result.auth.db).to.eql('somedb');
+      done();
+    });
+  });
+
   const specPath = path.join(__dirname, '../spec', 'initial-dns-seedlist-discovery');
   const testFiles = fs
     .readdirSync(specPath)