Inconsistent behavior when using ExVCR to test logic that makes HTTP requests in spawned processes about exvcr HOT 8 OPEN

Thanks for the extensive report and analysis, the 3 points you mentioned makes sense. Is there any ways you can try (or provide sample code?). If you can provide PR, that would be great too, though.

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I tried extracting something isolated and failed, sadly, so there's something going on I don't understand and I can't really provide you with our entire codebase. I'll keep an eye out to see if it happens again and can extract something at that time.

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Hi there,

@myronmarston Have you found a workaround to this issue ?

On my project, it's happening when I have a GenServer handle_call or handle_cast spawning a process that will have to to an HTTP request to HTTPoison, faked by ExVCR. And same as @myronmarston it's happening randomly.

For now, I do a try catch on that error to having it removed to the tests. But that's not a solution :

    spawn(fn ->
      try do
        function_using_http_poison
      rescue
        e in HTTPoison.Error ->
          nil
      end

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@myronmarston Have you found a workaround to this issue ?

Nope.

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I'm having the same problem when using HTTPoison.

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Something similar to #53 it happens when we have multiple requests in the test suite. Using HTTPoison and same issue.

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i have a similar issue with parallel requests being made #127 (sorry i just found this issue), i think both are related. i also added a minimum code sample of what i'm doing.

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It seems that network calls from spawned processes are not mocked at all. Upon switching off my wifi and running this test when a cassette is already populated, I receive an error which indicates the cassette was ignored and that it tried to make a network request.

The behaviour was the same even after turning on the global_mock config

defmodule Api.SomeTest.Test do
  use ExUnit.Case, async: false
  use ExVCR.Mock, adapter: ExVCR.Adapter.Hackney

  test "can get" do
    parent_pid = self()

    use_cassette "get_example_dotcom" do
      Process.spawn(
        fn ->
          res = HTTPoison.get("https://example.com")
          send(parent_pid, res)
        end,
        [:link]
      )
    end

    assert_receive {:ok, %{status_code: 200}}, 5000
  end
end

  1) test can get (Api.SomeTest.Test)
     test/api/get_example_test.exs:5
     Assertion failed, no matching message after 5000ms
     Showing 1 of 1 message in the mailbox
     code: assert_receive {:ok, %{status_code: 200}}
     mailbox:
       pattern: {:ok, %{status_code: 200}}
       value:   {:error, %HTTPoison.Error{__exception__: true, id: nil, reason: :nxdomain}}
     stacktrace:
       test/api/get_example_test.exs:18: (test)


Finished in 5.1 seconds (0.00s async, 5.1s sync)
1 test, 1 failure

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