binary_search_test.exs

defmodule Algorithms.Search.BinarySearchTest do
  alias Algorithms.Search.BinarySearch

  use ExUnit.Case

  describe "search/2 - example test cases" do
    test "finds element in the middle of the list" do
      assert BinarySearch.search([1, 3, 5, 7, 9], 5) == 2
    end

    test "finds element at the beginning of the list" do
      assert BinarySearch.search([1, 3, 5, 7, 9], 1) == 0
    end

    test "finds element at the end of the list" do
      assert BinarySearch.search([1, 3, 5, 7, 9], 9) == 4
    end

    test "returns -1 when element is not in the list" do
      assert BinarySearch.search([1, 3, 5, 7, 9], 4) == -1
    end

    test "works with an empty list" do
      assert BinarySearch.search([], 1) == -1
    end

    test "works with a single-element list" do
      assert BinarySearch.search([1], 1) == 0
      assert BinarySearch.search([1], 2) == -1
    end

    test "works with a large sorted list" do
      list = Enum.to_list(1..1000)
      assert BinarySearch.search(list, 500) == 499
      assert BinarySearch.search(list, 1001) == -1
    end

    test "handles duplicate elements" do
      assert BinarySearch.search([1, 2, 2, 3, 4, 5, 5, 6], 2) in [1, 2]
      assert BinarySearch.search([1, 2, 2, 3, 4, 5, 5, 6], 5) in [5, 6]
    end
  end
end