test.cs

[TestClass]
public class RepoTests
{
    UnitOfWork unitOfWork = new UnitOfWork(new MongoDataContext("mongodb://localhost:27017/sampledb"));

    [TestInitialize]
    public async Task Initialize()
    {
        var serkan = new User()
        {
            FirstName = "SERKAN",
            LastName  = "BIRCAN",
            Email     = "user@domain.com"
        };

        await unitOfWork.Users.AddNewAsync(serkan);
    }

    [TestCleanup]
    public async Task Cleanup()
    {
        await unitOfWork.Users.DeleteAllAsync();
    }

    [TestMethod]
    public void CheckConnection_When_Db_Available()
    {
        var isConnected = unitOfWork.CheckConnection();
        Assert.IsTrue(isConnected);
    }

    [TestMethod]
    public async Task GetByField_When_Its_Exist()
    {
        var users = await unitOfWork.Users.GetByFieldAsync("firstname", "SERKAN");
        Assert.IsTrue(users.Count() > 0);
    }

    [TestMethod]
    public async Task UpdateTest()
    {
        // Arrange
        var users = await unitOfWork.Users.GetByFieldAsync("firstname", "SERKAN");
        var user = users.FirstOrDefault();

        // Act
        var isUpdated = await unitOfWork.Users.UpdateAsync(user.Id, "email", "serkanbircan21@outlook.com");

        // Assert
        users = await unitOfWork.Users.GetByFieldAsync("firstname", "SERKAN");
        user = users.FirstOrDefault();

        Assert.IsTrue(isUpdated);
        Assert.AreEqual("serkanbircan21@outlook.com", user.Email);

    }

}