Mastering Moq: How to Test a Class that Gets IOptions Injected and Calls a SQL Server Stored Procedure

Are you tired of scratching your head, wondering how to Moq and test a class that gets IOptions injected and has a method that calls a SQL Server stored procedure? Well, wonder no more! In this comprehensive guide, we’ll take you through the step-by-step process of testing such a class using Moq, the popular .NET mocking library.

Setting the Stage

Before we dive into the testing process, let’s create a sample class that gets IOptions injected and has a method that calls a SQL Server stored procedure. This will serve as our example throughout the article.

public class MyService
{
    private readonly IOptions<MySettings> _settings;
    private readonly ILogger<MyService> _logger;
    private readonly SqlCommand _command;

    public MyService(IOptions<MySettings> settings, ILogger<MyService> logger, SqlCommand command)
    {
        _settings = settings;
        _logger = logger;
        _command = command;
    }

    public async Task<bool> SaveDataAsync(string data)
    {
        try
        {
            _logger.LogInformation("Saving data to database...");
            _command.CommandText = "dbo.SaveData";
            _command.CommandType = CommandType.StoredProcedure;
            _command.Parameters.AddWithValue("@data", data);
            await _command.ExecuteNonQueryAsync();
            return true;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error saving data to database");
            return false;
        }
    }
}

public class MySettings
{
    public string ConnectionString { get; set; }
}

Why Moq?

Moq is a popular .NET mocking library that allows us to create mock objects for our dependencies, making it easier to test our code in isolation. By using Moq, we can focus on testing the logic of our class without worrying about the complexities of its dependencies.

Creating Mock Objects with Moq

Before we start testing our class, we need to create mock objects for its dependencies. In this case, we need to create mock objects for IOptions<MySettings> and SqlCommand.

using Moq;

public class MyServiceTests
{
    [Fact]
    public async Task SaveDataAsync_ReturnsTrue_WhenDataSavedSuccessfully()
    {
        // Arrange
        var settings = new Mock<IOptions<MySettings>>();
        var logger = new Mock<ILogger<MyService>>();
        var command = new Mock<SqlCommand>();

        settings.SetupGet(s => s.Value).Returns(new MySettings { ConnectionString = "MockConnection" });

        // ... more code ...
    }
}

In the above code, we create mock objects for IOptions<MySettings> and SqlCommand using Moq’s Mock<T> class. We also set up the mock object for IOptions<MySettings> to return a mock MySettings object with a connection string.

Mocking SqlCommand and IOptions

Now that we have our mock objects, let’s take a closer look at how we can mock SqlCommand and IOptions.

Mocking SqlCommand

To mock SqlCommand, we need to set up its behavior for the ExecuteNonQueryAsync method. We can do this using Moq’s Setup method.

command.Setup(c => c.ExecuteNonQueryAsync(It.IsAny<CancellationToken>()))
    .ReturnsAsync(1); // Return a successful result

In the above code, we set up the mock SqlCommand object to return a successful result (1) when ExecuteNonQueryAsync is called.

Mocking IOptions

To mock IOptions, we need to set up its behavior for the Value property. We can do this using Moq’s SetupGet method.

settings.SetupGet(s => s.Value).Returns(new MySettings { ConnectionString = "MockConnection" });

In the above code, we set up the mock IOptions object to return a mock MySettings object with a connection string when the Value property is accessed.

Testing the Class

Now that we have our mock objects set up, let’s write a test for the SaveDataAsync method.

[Fact]
public async Task SaveDataAsync_ReturnsTrue_WhenDataSavedSuccessfully()
{
    // Arrange
    var settings = new Mock<IOptions<MySettings>>();
    var logger = new Mock<ILogger<MyService>>();
    var command = new Mock<SqlCommand>();

    settings.SetupGet(s => s.Value).Returns(new MySettings { ConnectionString = "MockConnection" });

    command.Setup(c => c.ExecuteNonQueryAsync(It.IsAny<CancellationToken>()))
        .ReturnsAsync(1); // Return a successful result

    var service = new MyService(settings.Object, logger.Object, command.Object);

    // Act
    var result = await service.SaveDataAsync("MockData");

    // Assert
    Assert.True(result);
    Assert FactoryBot.Moq.GetTimesCalled(c => c.ExecuteNonQueryAsync(It.IsAny<CancellationToken>())) == 1;
}

In the above test, we create a new instance of the MyService class, passing in our mock objects. We then call the SaveDataAsync method and assert that it returns true and that the ExecuteNonQueryAsync method was called once.

Conclusion

In this article, we’ve seen how to Moq and test a class that gets IOptions injected and has a method that calls a SQL Server stored procedure. We’ve covered how to create mock objects using Moq, set up their behavior, and write unit tests for our class.

By following these steps, you can ensure that your code is properly tested and behaves as expected, even when working with complex dependencies like IOptions and SqlCommand.

Table of Contents

• Setting the Stage
• Why Moq?
• Creating Mock Objects with Moq
• Mocking SqlCommand and IOptions
• Testing the Class
• Conclusion

By following this comprehensive guide, you’ll be well on your way to mastering Moq and testing complex classes with ease!

Frequently Asked Question

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