I am writing a graphql API for a restaurant. It allows clients to place orders. There are lots of integration tests that post graphql queries the API.

Tonight, I added the concept of “opening hours” and a test that posts a graphql “mutation” (a HTTP POST) is now failing, because the backend is checking DateTime.utc_now against the “opening hours” for the actual test time and deciding (correctly) that the business is closed.

Everything I read (tonight) about this sort of problem, talks about the functional way - directly injecting my own module to get utc_now. However, this is impossible for a request-response test of the API (you cannot send DateTime.utc_now over the network).

So, I went with this approach:

1. I tested the is_business_open logic on its own, in a functional way.
2. I got the API integration tests to pass by actually putting this in my code:

def validate_request_time(changeset) do
  if Mix.env == :test do
    changeset
  else
    if is_business_open() do
      changeset
    else
      put_error(changeset, :closed, "go to bed stupid")
    end
  end
end

Is this a bad idea? Please give me your unfiltered opinions/thoughts about this. Maybe somebody here has had a similar problem with real time in integration tests.