I tried to stub an API request as explained in Req docs as follows:
use ExUnit.Case, async: true
@mock_response """
{
"Realtime Currency Exchange Rate": {
"1. From_Currency Code": "EUR",
"2. From_Currency Name": "Euro",
"3. To_Currency Code": "CAD",
"4. To_Currency Name": "Canadian Dollar",
"5. Exchange Rate": "1.361",
"6. Last Refreshed": "2024-03-26 10:52:18.124709Z",
"7. Time Zone": "UTC",
"8. Bid Price": "1.361",
"9. Ask Price": "1.361"
}
}
"""
test "EUR to CAD rate" do
{:ok, pid} = RatesMonitor.start_link(name: :dummy_server)
Req.Test.stub(AlphaVantageApi, fn conn ->
Req.Test.json(conn, @mock_response)
end)
Req.Test.allow(RatesMonitor, self(), pid)
response = RatesMonitor.get_rates(pid, "eur", "cad")
IO.inspect(response, label: :test_response)
end
but it fails with error:
1) test EUR to CAD rate (PaymentServer.Exchange.AlphaVantageApiTest)
test/payment_server/exchange/alpha_vantage_api_test.exs:22
** (UndefinedFunctionError) function Req.Test.allow/3 is undefined or private. Did you mean:
* call/2
code: Req.Test.allow(RatesMonitor, self(), pid)
stacktrace:
(req 0.4.11) Req.Test.allow(PaymentServer.Exchange.RatesMonitor, #PID<0.415.0>, #PID<0.416.0>)
test/payment_server/exchange/alpha_vantage_api_test.exs:29: (test)
My RatesMonitor module is a GenServer:
defmodule PaymentServer.Exchange.RatesMonitor do
...
use GenServer
@default_server :rates_monitor
@refresh_interval :timer.seconds(5)
defmodule State do
@moduledoc """
Exchange server state
"""
defstruct from_currency: :usd, to_currency: :eur, rate: 1.0
end
# Client Interface
def start_link(opts \\ []) do
opts = Keyword.put_new(opts, :name, @default_server)
GenServer.start_link(__MODULE__, %State{}, opts)
end
def get_rates(pid \\ @default_server, from_currency, to_currency) do
GenServer.call(
pid,
{:get_rates, %State{from_currency: from_currency, to_currency: to_currency}}
)
end
@impl true
def handle_call({:get_rates, state}, _from, old_state) do
new_state = old_state
to_caller = fetch_rates(state)
{:reply, to_caller, new_state}
end
defp fetch_rates(%{from_currency: from_currency, to_currency: to_currency} = state) do
response = AlphaVantageApi.get_rates(from_currency, to_currency)
rate = Parser.parse(response)
%{state | from_currency: from_currency, to_currency: to_currency, rate: rate}
end
...
end
What’s wrong with this?
Thank you.
