How controllers handle validation errors?

[pranavbabu]

Good day everyone, I'm kinda stuck in understanding how controller returns :unprocessable_entity in case when bang methods raise an error, maybe someone can explain that to me? In my app if I don't handle it directly in controller it will raise an validation error.

  def create
    webhook = @board.webhooks.create!(webhook_params)
    redirect_to webhook
  end

test "create with invalid params" do
  board = boards(:writebook)
  assert_no_difference "Webhook.count" do
    post board_webhooks_path(board), params: {
      webhook: {
        name: "",
        url: "invalid-url"
      }
    }
  end

  assert_response :unprocessable_entity
end