test "should get destroy" do
    n = Supplier.count
    post :destroy, :id => 1
    assert_equal n - 1, Supplier.count
    assert_response :redirect
    assert_redirected_to :action => 'index'
    follow_redirect
    assert_tag :tag => 'div', :attributes => { :id => 'notice' },
        :content => '...'
  end

Admin::SupplierControllerTest#test_should_get_destroy:
NameError: undefined local variable or method `follow_redirect'