如何对Asp.Net MVC Identity UserManager.ChangePasswordAsync进行单元测试

[TestClass]
public class IdentityTests
{
    [TestMethod]
    public async Task ChangePasswordAsync_ShouldChangePassword()
    {
        // 准备测试环境
        var user = new ApplicationUser { UserName = "testuser" };
        var userManager = new UserManager<ApplicationUser>(new UserStore<ApplicationUser>());

        // 创建用户
        var result = await userManager.CreateAsync(user, "oldpassword");
        Assert.IsTrue(result.Succeeded);

        // 更改密码
        result = await userManager.ChangePasswordAsync(user.Id, "oldpassword", "newpassword");
        Assert.IsTrue(result.Succeeded);

        // 验证密码已更改
        var isValidPassword = await userManager.CheckPasswordAsync(user, "newpassword");
        Assert.IsTrue(isValidPassword);
    }
}