diff --git a/lib/mongo/db.rb b/lib/mongo/db.rb
index 2e8719b..e5610f5 100644
--- a/lib/mongo/db.rb
+++ b/lib/mongo/db.rb
@@ -167,6 +167,20 @@ module XGen
           end
         end
 
+        # Switches our socket to the master database. If we are already the
+        # master, no change is made.
+        def switch_to_master
+          master_str = master()
+          unless master_str == "#@host:#@port"
+            @semaphore.synchronize {
+              master_str =~ /(.+):(\d+)/
+              @host, @port = $1, $2
+              close()
+              @socket = TCPSocket.new(@host, @port)
+            }
+          end
+        end
+
         # Close the connection to the database.
         def close
           @socket.close
diff --git a/tests/test_db.rb b/tests/test_db.rb
new file mode 100644
index 0000000..9474b14
--- /dev/null
+++ b/tests/test_db.rb
@@ -0,0 +1,46 @@
+$LOAD_PATH[0,0] = File.join(File.dirname(__FILE__), '..', 'lib')
+require 'mongo'
+require 'test/unit'
+
+# NOTE: assumes Mongo is running
+class DBAPITest < Test::Unit::TestCase
+
+  include XGen::Mongo::Driver
+
+  def setup
+    host = ENV['MONGO_RUBY_DRIVER_HOST'] || 'localhost'
+    port = ENV['MONGO_RUBY_DRIVER_PORT'] || Mongo::DEFAULT_PORT
+    @db = Mongo.new(host, port).db('ruby-mongo-test')
+    @coll = @db.collection('test')
+    @coll.clear
+    @r1 = @coll.insert('a' => 1) # collection not created until it's used
+    @coll_full_name = 'ruby-mongo-test.test'
+  end
+
+  def teardown
+    @coll.clear unless @coll == nil || @db.socket.closed?
+  end
+
+  def test_close
+    @db.close
+    assert @db.socket.closed?
+    begin
+      @coll.insert('a' => 1)
+      fail "expected IOError exception"
+    rescue IOError => ex
+      assert_match /closed stream/, ex.to_s
+    end
+  end
+
+  def test_full_coll_name
+    assert_equal @coll_full_name, @db.full_coll_name(@coll.name)
+  end
+
+  def test_master
+    # Doesn't really test anything since we probably only have one database
+    # during this test.
+    @db.switch_to_master
+    assert_not_nil @db.socket
+  end
+
+end
diff --git a/tests/test_db_api.rb b/tests/test_db_api.rb
index eeefaa9..33f3c5a 100644
--- a/tests/test_db_api.rb
+++ b/tests/test_db_api.rb
@@ -196,17 +196,6 @@ class DBAPITest < Test::Unit::TestCase
     assert_equal 4, docs.size
   end
 
-  def test_close
-    @db.close
-    assert @db.socket.closed?
-    begin
-      @coll.insert('a' => 1)
-      fail "expected IOError exception"
-    rescue IOError => ex
-      assert_match /closed stream/, ex.to_s
-    end
-  end
-
   def test_drop_collection
     assert @db.drop_collection(@coll.name), "drop of collection #{@coll.name} failed"
     assert !@db.collection_names.include?(@coll_full_name)
@@ -253,10 +242,6 @@ class DBAPITest < Test::Unit::TestCase
     end
   end
 
-  def test_full_coll_name
-    assert_equal @coll_full_name, @db.full_coll_name(@coll.name)
-  end
-
   def test_index_information
     @db.create_index(@coll.name, 'index_name', ['a'])
     list = @db.index_information(@coll.name)