Add test case showing incorrect behaviour for failed searches
user
```ruby
# -*- ruby encoding: utf-8 -*-

describe Net::LDAP, "search method" do
  class FakeConnection
    def search(args)
      error_code = 1
      return error_code
    end
  end

  before(:each) do
    @connection = Net::LDAP.new
    @connection.instance_variable_set(:@open_connection, FakeConnection.new)
  end

  context "when returning result set" do
    it "should return nil upon error" do
      result_set = @connection.search(:return_result => true) do
      end
      result_set.should be_nil
    end
  end

  context "when returning boolean" do
    it "should return false upon error" do
      success = @connection.search(:return_result => false)
      success.should == false
    end
  end
end
```
assistant