I did work in a team that had multiple services in different technologies and there was a push to do consumer-driven contract testing with Pact and it got implemented for Ruby services. At that point the tooling for Elixir was not that great so we didn’t do it in the end, but I think the biggest reason was that it was always a low priority item for us - we did have an extensive set of tests for the API, so I saw little to no value (but significant effort) in adding Pact tests.
Instead of Pact I’d suggest writing unit tests (note that here the unit of the test is a behavior/endpoint, not a module/function) this way:
describe "GET /api/foobars" do
test "requires authorization" do
assert %{status: 401, body: body} = get(nil, "/api/foobars")
assert %{"error" => "Unauthorized"} = body
end
test "returns a list of foobars" do
assert %{"foobars" => []} = get!(api_key, "/api/foobars")
end
end
The idea here is to write your tests as if they were written using an external tool (you’ll need to add some helpers for making HTTP requests), but run them inside your normal test suite (mix test) to leverage all the ExUnit goodies and keep them fast.
