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Diego Novais
Diego Novais

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Game draw! Building the code and make the tests pass

#elixir #algorithms #webdev #tutorial

Now we'll code our module Game following the tests.

# lib/game.ex defmodule Game do @moduledoc """ Documentation for `Game`. """ end
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If we run the tests now:

mix test
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We'll see the tests failures:

 1) test Game.play/2 when the players draw when all players choose scissor (GameTest) test/game_test.exs:27 ** (UndefinedFunctionError) function Game.play/2 is undefined or private code: assert {:ok, match} = Game.play(first_player_choice, second_player_choise) stacktrace: (rock_paper_scissor_elixir 0.1.0) Game.play(3, 3) test/game_test.exs:31: (test) 2) test Game.play/2 when the players draw when all players choose paper (GameTest) test/game_test.exs:18 ** (UndefinedFunctionError) function Game.play/2 is undefined or private code: assert {:ok, match} = Game.play(first_player_choice, second_player_choise) stacktrace: (rock_paper_scissor_elixir 0.1.0) Game.play(2, 2) test/game_test.exs:22: (test) 3) test Game.play/2 when the players draw when all players choose stone (GameTest) test/game_test.exs:9 ** (UndefinedFunctionError) function Game.play/2 is undefined or private code: assert {:ok, match} = Game.play(first_player_choice, second_player_choise) stacktrace: (rock_paper_scissor_elixir 0.1.0) Game.play(1, 1) test/game_test.exs:13: (test) Finished in 0.02 seconds (0.00s async, 0.02s sync) 3 tests, 3 failures
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Let's make those tests pass

Firstly, we must create the function play passing two arguments, first_player_choice and second_player_choice:

defmodule Game do @moduledoc """ Documentation for `Game`. """ def play(first_player_choice, second_player_choice) do end end
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And then let's rerun the tests:

mix test
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 1) test Game.play/2 when the players draw when all players choose stone (GameTest) test/game_test.exs:9 match (=) failed code: assert {:ok, match} = Game.play(first_player_choice, second_player_choise) left: {:ok, match} right: nil stacktrace: test/game_test.exs:13: (test) 2) test Game.play/2 when the players draw when all players choose scissor (GameTest) test/game_test.exs:27 match (=) failed code: assert {:ok, match} = Game.play(first_player_choice, second_player_choise) left: {:ok, match} right: nil stacktrace: test/game_test.exs:31: (test) 3) test Game.play/2 when the players draw when all players choose paper (GameTest) test/game_test.exs:18 match (=) failed code: assert {:ok, match} = Game.play(first_player_choice, second_player_choise) left: {:ok, match} right: nil stacktrace: test/game_test.exs:22: (test) Finished in 0.03 seconds (0.00s async, 0.03s sync) 3 tests, 3 failures
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Now we need to guarantee that the game will draw if the player chooses the same item:

defmodule Game do @moduledoc """ Documentation for `Game`. """ def play(first_player_choice, second_player_choice) do result(first_player_choice, second_player_choice) end defp result(first_player_choice, second_player_choice) do cond do first_player_choice == second_player_choice -> {:ok, "Draw!"} end end end
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And now, if we rerun the tests:

mix test
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Everything passed, and everything was ok.

... Finished in 0.02 seconds (0.00s async, 0.02s sync) 3 tests, 0 failures Randomized with seed 352470
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In the next post, we'll build the tests covering the scenario when the first player wins.

Contacts

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