text: import pytest
  from main import Solution
  
  
  def test_solution_1():
      sol = Solution()
      x = [7, 1, 5, 3, 6, 4]
      result = sol.max_profit(x)
      assert result == 7
  
  
  def test_solution_2():
      sol = Solution()
      x = [1, 2, 3, 4, 5]
      result = sol.max_profit(x)
      assert result == 4
  
  
  def test_solution_3():
      sol = Solution()
      x = [7, 6, 4, 3, 1]
      result = sol.max_profit(x)
      assert result == 0
  