October 31st, 2023 - TDD with Livebook

Tests

TDD = Test Driven Development

ExUnit.start(auto_run: false)

defmodule CalculatorTest do
  use ExUnit.Case, async: false

  describe "Testing the addition function" do
    test "2 plus 3 is 5" do
      assert Calculator.add(2, 3) == 5
    end

    test "2 plus 2 is 4" do
      assert Calculator.add(2, 2) == 4
    end
  end

  describe "Testing the multiplication function" do
    test "2 times 3 is 6" do
      assert Calculator.multiply(2, 3) == 6
    end

    test "2 times 20 is 40" do
      assert Calculator.multiply(2, 20) == 40
    end
  end
end

ExUnit.run()

Code

defmodule Calculator do
  def add(a, b) do
    a + b
  end

  def multiply(a, b) do
    a * b
  end
end

Second example

Tests

ExUnit.start(auto_run: false)

defmodule MethodTest do
  use ExUnit.Case, async: false

  describe "Testing the square root function" do
    test "the square root of 9 is 3.0" do
      assert Method.sqrt(9) == 3.0
    end

    test "the square root of 16 is 4.00..." do
      assert Method.sqrt(16) == 4.0
    end
  end

  describe "Testing the power function" do
    test "3 raised to the power of 2 is 9" do
      assert Method.pow(3, 2) == 9.0
    end
  end

  describe "Testing the cubic root function" do
    test "the cubic root of 27 is 3.0" do
      assert Method.cbcrt(27) == 3.0
    end

    test "the cubic root of 64 is 4.0" do
      assert_in_delta Method.cbcrt(64), 4.0, 0.00000000000001
    end
  end
end

ExUnit.run()

Code

defmodule Method do
  def sqrt(x) do
    x ** (1 / 2)
  end

  def pow(base, exponent) do
    base ** exponent
  end

  def cbcrt(x) do
    x ** (1 / 3)
  end
end

Method.sqrt(16)