Find fixed point algorithm spec file

find_fixed_point_spec.rb

RSpec.describe BinarySearch, "#find_fixed_point" do
  context "should have a sorted array" do
    it "searches for the fixed point" do
      binary_search = BinarySearch.new
      expect(binary_search.find_fixed_point([0, 2, 3, 4, 5, 6, 7, 8])).to eql 0
      expect(binary_search.find_fixed_point([0, 1, 2, 4, 5, 6, 7, 8])).to eql 2
    end
    it "returns -1 if not found" do
      binary_search = BinarySearch.new
      expect(binary_search.find_fixed_point([1, 2, 3, 4, 5, 6, 7, 8])).to eql -1
    end
  end
end