Revising Azure Functions Dependency Injection

app-module.cs

public class AppModule : Module
{
    public override void Load(IServiceCollection services)
    {
        services.AddSingleton<AppSettings>();
        services.AddTransient<IGetSamplesFunction, GetSamplesFunction>();
    }
}

get-samples-http-trigger-test.cs

[TestMethod]
public async Task Given_Request_Response_Should_Return_Result()
{
    var logger = new Mock<ILogger>();

    var function = new Mock<IGetSamplesFunction>();
    function.SetupProperty(p => p.Log, logger.Object);

    var result = new ObjectResult("hello world");
    function.Setup(p => p.InvokeAsync<HttpRequest, IActionResult>(
            It.IsAny<HttpRequest>(),
            It.IsAny<FunctionOptionsBase>()))
        .ReturnsAsync(result);

    var trigger = new SampleHttpTrigger2(function.Object);

    var req = new Mock<HttpRequest>();
    var log = new Mock<ILogger>();

    var response = await trigger.GetSamples2(req.Object, log.Object).ConfigureAwait(false);
    response.Should().BeOfType<ObjectResult>();

    var @return = response as ObjectResult;
    @return.Value.Should().Be("hello world");
}

sample-http-trigger-1.cs

public static class SampleHttpTrigger1
{
    public static IFunctionFactory Factory { get; set; } = new FunctionFactory(new AppModule());

    [FunctionName(nameof(GetSamples1))]
    public static async Task<IActionResult> GetSamples1(
        [HttpTrigger(AuthorizationLevel.Function, "post", Route = "samples1")] HttpRequest req,
        ILogger log)
    {
        var options = new GetSamplesFunctionOptions("sample 1");
        var result = await Factory.Create<IGetSamplesFunction, ILogger>(log)
                                  .InvokeAsync<HttpRequest, IActionResult>(req, options)
                                  .ConfigureAwait(false);

        return result;
    }
}

sample-http-trigger-2.cs

public class SampleHttpTrigger2
{
    private readonly IGetSamplesFunction _function;

    public SampleHttpTrigger2(IGetSamplesFunction function)
    {
        this._function = function ?? throw new ArgumentNullException(nameof(function));
    }

    [FunctionName(nameof(GetSamples2))]
    public async Task<IActionResult> GetSamples2(
        [HttpTrigger(AuthorizationLevel.Function, "post", Route = "samples2")] HttpRequest req,
        ILogger log)
    {
        this._function.Log = log;

        var options = new GetSamplesFunctionOptions("sample 2");
        var result = await this._function
                               .InvokeAsync<HttpRequest, IActionResult>(req, options)
                               .ConfigureAwait(false);

        return result;
    }
}

sample-http-trigger.cs

public class SampleHttpTrigger
{
    [FunctionName(nameof(GetSamples))]
    public async Task<IActionResult> GetSamples(
        [HttpTrigger(AuthorizationLevel.Function, "get", Route = "samples")] HttpRequest req,
        ILogger log)
    {
        var name = req.Query["name"];

        return new OkObjectResult($"Hello {name}");
    }
}

startup.cs

// Registger assembly
[assembly: WebJobsStartup(typeof(StartUp))]
namespace Sample.FunctionApp
{
    // Implement IWebJobStartup interface.
    public class StartUp : IWebJobsStartup
    {
        public void Configure(IWebJobsBuilder builder)
        {
            builder.Services.AddSingleton<AppSettings>();

            builder.Services.AddTransient<IGetSamplesFunction, GetSamplesFunction>();
        }
    }
}