test.rb

def create
  @user = User.find_by_email params[:email]

  if @user && @user.valid_password?(password)
    return redirect_to_oauth_complete(@user.account) if oauth_session?
    sign_in @user
    redirect_to [:dashboard]
  else
    flash[:error] = 'You have entered an invalid email or password. Please try again.'
    render :new
    flash.clear
  end
end