analog of `let` in ExUnit

Question

As you know, rspec supports let in its tests. It's quite helpful and shorts code a lot by predefining common variables and share them between tests.

How can I invoke this functionality in ExUnit?

Answer 1

I think the better way to have the same behavior on Elixir with ExUnit, is using setup_all or setup.

The setup_all callbacks are invoked once to setup the test case before any test is run and all setup callbacks are run before each test. No callback runs if the test case has no tests or all tests were filtered out.

Complete documentation can be found here: https://hexdocs.pm/ex_unit/ExUnit.Callbacks.html

Answer 2

I think the closest analog is returning a context from a setup hook. Take a look at this example adapted from the ExUnit.Callbacks documentation:

defmodule AssertionTest do
  use ExUnit.Case, async: true

  setup do
    {:ok, hello: "world"}
  end

  test "a test", context do
    assert(context[:hello] == "world")
  end
end