编写程序，创建一个实现+、-、、/和*（幂）运算的模块MyMath.py，并编写测试代码。

为了编写一个名为`MyMath.py`的模块，用于实现基本数学运算，包括加法(+), 减法(-), 乘法(*), 除法(/)以及求幂(**)，你可以按照下面的方式组织：

# MyMath.py
class MathOperations:
    def add(self, a, b):
        return a + b

    def subtract(self, a, b):
        return a - b

    def multiply(self, a, b):
        return a * b

    def divide(self, a, b):
        if b != 0:
            return a / b
        else:
            raise ValueError("Cannot divide by zero.")

    def power(self, a, b):
        return a ** b

# 测试代码 (test_mymath.py)
import unittest
from MyMath import MathOperations

class TestMyMath(unittest.TestCase):

    def setUp(self):
        self.math_obj = MathOperations()

    def test_addition(self):
        result = self.math_obj.add(5, 3)
        self.assertEqual(result, 8)

    def test_subtraction(self):
        result = self.math_obj.subtract(7, 4)
        self.assertEqual(result, 3)

    def test_multiplication(self):
        result = self.math_obj.multiply(6, 2)
        self.assertEqual(result, 12)

    def test_division(self):
        result = self.math_obj.divide(10, 2)
        self.assertAlmostEqual(result, 5)

    def test_power(self):
        result = self.math_obj.power(2, 3)
        self.assertEqual(result, 8)

    #