Elixir: Supervisors

🚧 In development

Instructions

🚧 In development

The exercise doesn't pass checking. What to do? 😶

If you've reached a deadlock it's time to ask your question in the «Discussions». How ask a question correctly:

Be sure to attach the test output, without it it's almost impossible to figure out what went wrong, even if you show your code. It's complicated for developers to execute code in their heads, but having a mistake before their eyes most probably will be helpful.

In my environment the code works, but not here 🤨

My code is different from the teacher's one 🤔

I've read the lessons but nothing is clear 🙄

Прочитал урок — ничего не понятно 🙄

Found a bug? Have something to add? Pull requests are welcome!

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Your exercise will be checked with these tests:

defmodule Test do
  use ExUnit.Case

  describe "incrementor code unchanged" do
    test "current_value work" do
      Incrementor.start_link()

      assert Incrementor.current_value() == 0
    end

    test "run work" do
      Incrementor.start_link()

      Incrementor.run()
      assert Incrementor.current_value() == 1

      Incrementor.run()
      assert Incrementor.current_value() == 2
    end
  end

  describe "decrementor code unchanged" do
    test "current_value work" do
      Decrementor.start_link()

      assert Decrementor.current_value() == 0
    end

    test "run work" do
      Decrementor.start_link()

      Decrementor.run()
      assert Decrementor.current_value() == -1

      Decrementor.run()
      assert Decrementor.current_value() == -2
    end
  end

  describe "solution supervisor work" do
    test "initialization work" do
      {:ok, pid} = Solution.start_link()

      assert [
               {Decrementor, _, :worker, [Decrementor]},
               {Incrementor, _, :worker, [Incrementor]}
             ] = Supervisor.which_children(pid)

      assert Supervisor.count_children(pid) == %{active: 2, workers: 2, supervisors: 0, specs: 2}
    end

    test "restart straregy" do
      {:ok, pid} = Solution.start_link()

      Decrementor.run()
      assert Decrementor.current_value() == -1

      Incrementor.run()
      assert Incrementor.current_value() == 1

      Process.exit(Process.whereis(Decrementor), :kill)
      Supervisor.restart_child(pid, Process.whereis(Decrementor))
      assert Supervisor.count_children(pid) == %{active: 2, workers: 2, supervisors: 0, specs: 2}
      assert Decrementor.current_value() == 0
      assert Incrementor.current_value() == 1

      Process.exit(Process.whereis(Incrementor), :kill)
      Supervisor.restart_child(pid, Process.whereis(Incrementor))
      assert Supervisor.count_children(pid) == %{active: 2, workers: 2, supervisors: 0, specs: 2}
      assert Decrementor.current_value() == 0
      assert Incrementor.current_value() == 0
    end
  end
end

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Teacher's solution will be available in:

20:00

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