针对生产数据库进行单元测试的做法是不可取的，因为会对数据库中的数据造成影响。正确的做法是使用“内存数据库”（In-Memory database）或者模拟数据来执行测试。以下是在ASP.NET Core Web API中使用“内存数据库”进行单元测试的示例代码：

public class TestDbContext : DbContext
{
    public TestDbContext(DbContextOptions options)
        : base(options)
    {
    }

    public DbSet Users { get; set; }
}

[TestMethod]
public async Task GetUserById_ReturnsUser()
{
    var options = new DbContextOptionsBuilder()
        .UseInMemoryDatabase(databaseName: "TestDatabase")
        .Options;

    // Insert test data into the "database"
    using (var context = new TestDbContext(options))
    {
        context.Users.Add(new User { Id = 1, Name = "John Smith" });
        await context.SaveChangesAsync();
    }

    // Run the test
    using (var context = new TestDbContext(options))
    {
        var controller = new UsersController(context);
        var result = await controller.GetUserById(1);

        // Assert that the expected user was returned
        Assert.AreEqual("John Smith", result.Value.Name);
    }
}

另一种解决方案是使用仓库层（Repository Layer），这可将数据库访问逻辑隔离到一个单独的层级中，从而使测试更容易进行。以下是在ASP.NET Core Web API中使用仓库层进行单元测试的示例代码：

public interface IUserRepository
{
    Task GetById(int id);
}

public class UserRepository : IUserRepository
{
    private readonly TestDbContext _context;

    public UserRepository(TestDbContext context)
    {
        _context = context;
    }

    public Task GetById(int id)
    {
        return _context.Users.FindAsync(id);
    }
}

[TestMethod]
public async Task GetUserById_ReturnsUser()
{
    var options = new DbContextOptionsBuilder()
        .UseInMemoryDatabase