Testing Azure Blob Storage using azurite

Question

I have a C# library that uses Azure Blob Storage. I have an integration test for this that uses the azurite blob storage emulator. Having installed the Azurite nuget package the blob.exe emulator runs immediately and my test passes. However, I want the test to start up and close down cleanly so:

• Startup - launch blob storage emulator
• Close down - Clean up temporary storage and stop emulator

Does anyone have a neat pattern for this?

Answer 1

I ended up with the following solution:

(a) As part of dev setup, download azurite to a well-known location and set an environment variable to point to blob.exe:

InstallBlobExe.bat:

nuget restore packages.config -DirectDownload -PackagesDirectory "..\packages"

set BLOB_EXE="%CD%\..\packages\Azurite.2.6.5\tools\blob.exe"

packages.config:

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="azurite" version="2.6.5" targetFramework="net471" />
</packages>

(b) In tests, use a helper class to start and stop blob.exe.

using System;
using System.Diagnostics;
using System.IO;

namespace AltostratusEventsTests
{
    // https://stackoverflow.com/questions/55043372/testing-azure-blob-storage-using-azurite
    public class AzuriteBlobEmulator : IDisposable
    {
        private Process _blobProcess;

        public AzuriteBlobEmulator()
        {
            StartEmulator();
        }

        public void Dispose()
        {
            StopEmulator();
        }

        private void StartEmulator()
        {
            _blobProcess = new Process();
            _blobProcess.StartInfo.FileName = BlobDotExePath();
            _blobProcess.StartInfo.Arguments = BlobDotExeArgs();
            _blobProcess.StartInfo.WindowStyle = ProcessWindowStyle.Minimized;
            _blobProcess.Start();
        }

        private void StopEmulator()
        {
            try
            {
                _blobProcess.Kill();
                _blobProcess.WaitForExit();
            }
            catch
            {

            }
        }

        private string BlobDotExePath()
        {
            var blobPath = Environment.GetEnvironmentVariable("BLOB_EXE");
            if (string.IsNullOrEmpty(blobPath))
            {
                throw new NotSupportedException(@"

The BLOB_EXE environment variable must be set to the location of the azurite blob emulator.  
This can be done by running InstallBlobExe.bat

");
            }
            return blobPath;
        }

        private string BlobDotExeArgs()
        {
            return "-l " + Directory.GetCurrentDirectory();
        }
    }
}