[Elixir] ユニットテストの書き方

ユニットテストの書き方

mixを使うまでの間、１本のプログラムでユニットテストを書いてゆくには、たとえば以下のように書きます。

add_test.exs

ExUnit.start()

defmodule AddTest do
  use ExUnit.Case
  test "add test" do
    assert 1+1==2
    assert 1+2==2
  end
end

実行すると、

$ elixir add_test.exs 


  1) test add test (AddTest)
     add_test.exs:4
     Assertion with == failed
     code: 1 + 2 == 2
     lhs:  3
     rhs:  2
     stacktrace:
       add_test.exs:6: (test)



Finished in 0.03 seconds (0.03s on load, 0.00s on tests)
1 test, 1 failure

Randomized with seed 375518

ユニットテスト１日目のコードです。

first_test.exs

ExUnit.start()

defmodule StringTest do
  use ExUnit.Case
  test "basic" do
    assert "abc"<>"def" === "abcdef"
    assert String.length("abc") === 3
    assert String.slice("abcdef",2..3) === "cd"
    assert String.split("abc def"," ") === ["abc","def"]
    assert Enum.join(["abc","def"],",") === "abc,def"

    assert String.at("abcdef",0) === "a"
    assert String.at("abcdef",1) === "b"
    assert String.starts_with?("abcdef","abc")
    assert String.ends_with?("abcdef","def")
    assert String.trim("  abc  \n") == "abc"
    assert String.upcase("aBc") == "ABC"
    assert String.downcase("AbC") == "abc"
    assert String.to_integer("16") == 16
    assert String.to_integer("1E",16) == 30
  end
  test "complex" do
    assert(Enum.map(["abc","def"],&String.upcase(&1)) == ["ABC","DEF"])
    assert Enum.map(["10","20"],&(String.to_integer(&1))) == [10,20]
    assert Enum.map(["10","20"],&String.to_integer/1) == [10,20]

    with to_i = &(String.to_integer(&1))
    do
      assert to_i.("10") == 10
      assert Enum.map(["10","20"], to_i) == [10,20]
    end

    with line = "100 200\n"
    do
      result = line 
               |> String.trim 
               |> String.split 
               |> (Enum.map &String.to_integer(&1))  # to_integer/1
      assert result == [100,200]
    end

  end
  test "embed" do
    num = 123
    assert "num=#{num}" === "num=123"    
    name = "foo"
    assert "name=#{name}" === "name=foo"    
    assert 'name=#{name}' === 'name=foo'    
  end
  test "regex" do
    assert String.to_integer("1E",16) == 30
  end
end

defmodule ListTest do
  use ExUnit.Case
  test "list" do
    assert Enum.to_list(1..3) == [1,2,3]
    assert [1,2,3]++[4,5,6] == [1,2,3,4,5,6]
    assert Enum.concat([1,2,3],[4,5,6]) == [1,2,3,4,5,6]

    with n=1,
     list=[2,3]
    do
      assert [n|list] === [1,2,3]
    end

    with list = [1,2,3]
    do
      assert (hd list) === 1
      assert (tl list) === [2,3]
    end

    with list = [1,2,3]
    do
      [head|tail] = list
      assert head === 1
      assert tail === [2,3]
    end

    with [first,second] = [1,2]
    do
      assert first == 1
      assert second == 2
    end
  end
end

その実行結果

$ elixir first_test.exs 
.....

Finished in 0.09 seconds (0.08s on load, 0.01s on tests)
5 tests, 0 failures

Randomized with seed 703309

楽しんでね！