How to write a Unit testing for Azure Function app? - unit-testing

Question

I have an azure function based on .Net core 3.1. It triggers when a file is uploaded into the Azure Blob Container, processes the CSV file and updates the database
Below is the code excerpt
FileTrigger.cs
namespace aspnetcore_azurefun_blob
{
[StorageAccount("AzureWebJobsStorage")]
public class FileTrigger
{
#region Property
private readonly IFileProcessor fileProcessor;
#endregion
#region Constructor
public FileTrigger(IFileProcessor fileProcessor)
{
this.fileProcessor = fileProcessor;
}
#endregion
[FunctionName("FileTrigger")]
public void ProcessFilesFromSamplesContainer([BlobTrigger("samples-workitems/{name}")]Stream myBlob, string name, ILogger log, ExecutionContext context)
{
log.LogInformation("Function: ProcessFilesFromSamplesContainer is called");
log.LogInformation($"C# Blob trigger function Processed blob\n Name:{name} \n Size: {myBlob.Length} Bytes");
var result = fileProcessor.ProcessAsync(myBlob, name, log, context);
log.LogInformation($"Function Completed {result.Result} on {DateTime.Now.ToLongDateString()} # {DateTime.Now.ToShortTimeString()}.\n.");
}
}
}
FileProcessor.cs
namespace ClientCore.Processor
{
public interface IFileProcessor
{
Task<string> ProcessAsync(Stream myBlob, string name, ILogger log, ExecutionContext context);
}
public class FileProcessor : IFileProcessor
{
#region Property
private readonly IFileProcessingServiceFacade fileProcessingService;
#endregion
#region Constructor
public FileProcessor(IFileProcessingServiceFacade fileProcessingService)
{
this.fileProcessingService = fileProcessingService;
}
#endregion
#region Public Methods
public async Task<string> ProcessAsync(Stream myBlob, string name, ILogger log, ExecutionContext context)
{
var processingResult = fileProcessingService.ProcessAsync(myBlob, name, log, context);
return await Task.FromResult($"{processingResult.Result}");
}
#endregion
}
}
FileProcessingService.cs
namespace BusinessService.Services
{
public interface IFileProcessingServiceFacade
{
Task<string> ProcessAsync(Stream myBlob, string name, ILogger log, ExecutionContext context);
}
partial class FileProcessingServiceFacade : IFileProcessingServiceFacade
{
#region Public Methods
public async Task<string> ProcessAsync(Stream myBlob, string name, ILogger log, ExecutionContext context)
{
// Get the Contents from the CSV File
var csvData = GetCSVData(myBlob);
AppDbContext.FileRecords.Add(new FileRecords
{
FileName = name,
IsCompleted = DefaultValues.IsCompleted
});
AppDbContext.SaveChanges();
log.LogInformation($"Reading configuration from the configuration settings file: {Configurator.AzureSQLServerConfigurator.ConnnectionString}");
log.LogInformation("Database is updated..!");
return await Task.FromResult($"success");
}
#endregion
}
partial class FileProcessingServiceFacade : ServiceBase<FileProcessingServiceFacade>
{
#region Constructor
public FileProcessingServiceFacade(AppDbContext appDbContext, IOptions<AppConfigurator> configurator)
: base(appDbContext, configurator) { }
#endregion
#region Extract Data from CSV
protected static List<dynamic> GetCSVData(Stream jobData)
{
try
{
#region CsvHelper Mapping and Conversion
var csvHelperConfig = new CsvHelper.Configuration.CsvConfiguration(CultureInfo.InvariantCulture)
{
NewLine = Environment.NewLine,
PrepareHeaderForMatch = args => args.Header.ToUpper().Replace(" ", ""),
HasHeaderRecord = true
};
using var reader = new StreamReader(jobData);
using var csvHelper = new CsvReader(reader, CultureInfo.InvariantCulture);
csvHelper.Context.RegisterClassMap<StudentDetailsMap>();
var csvHelperRrecords = csvHelper.GetRecords<StudentDetails>()
.Where(x => !string.IsNullOrWhiteSpace(x.Name))
.OrderBy(x => x.ID);
return csvHelperRrecords.Cast<dynamic>().ToList();
#endregion
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
#endregion
}
}
How to write a Unit testing for the above Azure Function app? Just a head start is required.