#structure map

Ok so I managed to pull ConfigurationManager.AppSettings[key]; out into an interface because my test could not access web.config to load a string.

Brilliant (I thought), I was able to mock the IConfiguration like so:

public class PortalConfiguration : IConfiguration {   public string GetAppSetting(string key)   {     return ConfigurationManager.AppSettings[key];   } }

then in my unit test:

_mockConfiguration = new Mock<IConfiguration>();

_mockConfiguration   .Setup(m => m.GetAppSetting(It.IsAny<string>()))   .Returns("http://localhost:8090");

which worked because previously, the method I was testing had a hard coded

ConfigurationManager.AppSettings[key];

in it - which was null - so the test failed.

Now I had a passing test and felt good.

Then I tried to run my application and it crashed because I had to inject a concrete IConfiguration (using StructureMap) into a class at runtime.

This is what caused the problem:

public Startup(IConfiguration configuration) {   _configuration = configuration; }

I could not modify the caller of this class becuase it lived beyond my code somewhere in the .NET framework.

So I did this instead:

public Startup() {   // cannot pass IConfiguration through ctor because   // the core/metadata expects an empty constructor   _configuration = IocConfig.Setup().GetInstance<IConfiguration>(); }

Which essentially does the same thing - it asks my DI Container for which concrete implementation to use (just as it would do if I could have used the code that caused the problem.