Unit test for .NetCore startup configuration fails

Question

I have a windows service application created with.NetCore. I want to create some unit tests for service methods.

The startup class looks like this

public class Startup
{
    public static IConfiguration Configuration;

    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }
    
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
    }
}

The class that needs to be tested

public class ModelConsumer : IModelConsumer
{        
    private readonly IProcessHandler _processHandler;

    public ModelConsumer(IIProcessHandler processHandler)
    {
        _processHandler = processHandler;
    }

    public void OnMessageReceived(ModelDto model)
    {
        var exportFolder = Startup.Configuration["ExportFolder"];           
        
       // do actions
    }
}

The test class

[TestClass]
public class ModelConsumerTests
{
    [TestMethod]
    public void OnMessageReceived()
    {
        var processHandler = new Mock<IProcessHandler>();
        var modelConsumer = new ModelConsumer(processHandler.Object);

        var config = InitConfiguration();
        var _exportFolder = config["ExportFolder"];

        modelConsumer.OnMessageReceived(new ModelDto());

        // verify mock call actions
    }

    public static IConfiguration InitConfiguration()
    {
        var config = new ConfigurationBuilder()
            .AddJsonFile("appsettings.json")
            .Build();
        return config;
    }
}

When I run the test method I receive the following error

There is something that is missing from the configuration, so the test could run successfully?

Answer 1

It's expecting appsettings.json in the bin/ folder of the Test project. So you'll have to copy it into the test project / make a new one and make sure it gets copied to the output on build.