sure/test/controllers/plaid_items_controller_test.rb

require "test_helper"
require "ostruct"

class PlaidItemsControllerTest < ActionDispatch::IntegrationTest
  setup do
    sign_in @user = users(:family_admin)
  end

  test "new redirects with friendly alert when Plaid rejects link_token request for unauthorized products" do
    # Reproduces issue #1792: the Plaid client account isn't enabled for the
    # requested products, so Plaid returns an actionable error message. We
    # should surface that message instead of letting the modal frame render
    # blank.
    plaid_provider = mock
    Provider::Registry.stubs(:plaid_provider_for_region).with(:us).returns(plaid_provider)

    error_body = {
      "error_code" => "INVALID_PRODUCT",
      "error_message" => "Your account is not enabled for the following products: [\"investments\" \"liabilities\" \"transactions\"]. To request access, visit https://dashboard.plaid.com/overview/request-products or contact Sales or your Account Manager."
    }.to_json
    plaid_provider.expects(:get_link_token).raises(
      Plaid::ApiError.new(code: 400, response_body: error_body)
    )

    get new_plaid_item_url(accountable_type: "Investment")

    assert_redirected_to accounts_path
    assert_match(/not enabled for the following products/, flash[:alert])
  end

  test "new redirects with generic alert when Plaid raises an unclassified error" do
    plaid_provider = mock
    Provider::Registry.stubs(:plaid_provider_for_region).with(:us).returns(plaid_provider)

    plaid_provider.expects(:get_link_token).raises(
      Plaid::ApiError.new(code: 500, response_body: { "error_code" => "INTERNAL_SERVER_ERROR" }.to_json)
    )

    get new_plaid_item_url

    assert_redirected_to accounts_path
    assert_equal I18n.t("plaid_items.errors.link_token_generic"), flash[:alert]
  end

  test "edit redirects with friendly alert when Plaid rejects update link_token request" do
    plaid_item = plaid_items(:one)
    error_body = {
      "error_code" => "INVALID_PRODUCT",
      "error_message" => "Your account is not enabled for the following products: [\"transactions\"]."
    }.to_json
    PlaidItem.any_instance.expects(:get_update_link_token).raises(
      Plaid::ApiError.new(code: 400, response_body: error_body)
    )

    get edit_plaid_item_url(plaid_item)

    assert_redirected_to accounts_path
    assert_match(/not enabled for the following products/, flash[:alert])
  end

  test "create" do
    @plaid_provider = mock
    Provider::Registry.expects(:plaid_provider_for_region).with("us").returns(@plaid_provider)

    public_token = "public-sandbox-1234"

    @plaid_provider.expects(:exchange_public_token).with(public_token).returns(
      OpenStruct.new(access_token: "access-sandbox-1234", item_id: "item-sandbox-1234")
    )

    assert_difference "PlaidItem.count", 1 do
      post plaid_items_url, params: {
        plaid_item: {
          public_token: public_token,
          region: "us",
          metadata: { institution: { name: "Plaid Item Name" } }
        }
      }
    end

    assert_equal "Account linked successfully.  Please wait for accounts to sync.", flash[:notice]
    assert_redirected_to accounts_path
  end

  test "destroy" do
    delete plaid_item_url(plaid_items(:one))

    assert_equal "Accounts scheduled for deletion.", flash[:notice]
    assert_enqueued_with job: DestroyJob
    assert_redirected_to accounts_path
  end

  test "sync" do
    plaid_item = plaid_items(:one)
    PlaidItem.any_instance.expects(:sync_later).once

    post sync_plaid_item_url(plaid_item)

    assert_redirected_to accounts_path
  end

  test "select_existing_account redirects when no available plaid accounts" do
    account = accounts(:depository)

    get select_existing_account_plaid_items_url(account_id: account.id, region: "us")
    assert_redirected_to account_path(account)
    assert_equal "No available Plaid accounts to link. Please connect a new Plaid account first.", flash[:alert]
  end

  test "link_existing_account links plaid account to existing account" do
    account = accounts(:depository)

    # Create a new unlinked plaid_account for testing
    plaid_account = PlaidAccount.create!(
      plaid_item: plaid_items(:one),
      name: "Test Plaid Account",
      plaid_id: "test_acc_123",
      plaid_type: "depository",
      plaid_subtype: "checking",
      currency: "USD",
      current_balance: 1000,
      available_balance: 1000
    )

    assert_not account.linked?
    assert_nil plaid_account.account
    assert_nil plaid_account.account_provider

    assert_difference "AccountProvider.count", 1 do
      post link_existing_account_plaid_items_url, params: {
        account_id: account.id,
        plaid_account_id: plaid_account.id
      }
    end

    account.reload
    assert account.linked?, "Account should be linked after creating AccountProvider"
    assert_equal 1, account.account_providers.count
    assert_redirected_to accounts_path
    assert_equal "Account successfully linked to Plaid", flash[:notice]
  end
end