FunctionTestFixture.cs

public class FunctionTestFixture : IDisposable
{
    private readonly Process _funcHostProcess;

    public int Port { get; } = 7001;

    public readonly HttpClient Client = new HttpClient();

    public FunctionTestFixture()
    {
        var dotnetExePath = Environment.ExpandEnvironmentVariables(ConfigurationHelper.Settings.DotnetExecutablePath);
        var functionHostPath = Environment.ExpandEnvironmentVariables(ConfigurationHelper.Settings.FunctionHostPath);
        var functionAppFolder = Path.GetRelativePath(Directory.GetCurrentDirectory(), ConfigurationHelper.Settings.FunctionApplicationPath);

        _funcHostProcess = new Process
        {
            StartInfo =
            {
                FileName = dotnetExePath,
                Arguments = $"\"{functionHostPath}\" start -p {Port}",
                WorkingDirectory = functionAppFolder
            }
        };
        var success = _funcHostProcess.Start();
        if (!success)
        {
            throw new InvalidOperationException("Could not start Azure Functions host.");
        }

        Client.BaseAddress = new Uri($"http://localhost:{Port}");
    }

    public virtual void Dispose()
    {
        if (!_funcHostProcess.HasExited)
        {
            _funcHostProcess.Kill();
        }

        _funcHostProcess.Dispose();
    }
}