Where to validate AutoMapper Configuration in ASP.Net Core application?

Question

Building an ASP.Net Core 2.0 web application and can't figure out where to validate the AutoMapper configuration.

In my ConfigureServices() method, I have

services.AddAutoMapper();

And I'm registering my mappings in an Automapper Profile

public class MyAutomapperProfile : Profile
{
    public MyAutomapperProfile()
    {
        CreateMap<FooDto, FooModel>();
        CreateMap<BarDto, BarModel>();
    }
}

But it's not clear where to call

Mapper.Configuration.AssertConfigurationIsValid();

Answer 1

After digging around in the IMapper interface (and thanks to the documentation link provided by @LucianBargaoanu), I found exactly what I needed.

In ConfigureServices():

        // Adds AutoMapper to DI configuration and automagically scans the 
        // current assembly for any classes that inherit Profile 
        // and registers their configuration in AutoMapper
        services.AddAutoMapper();

The secret sauce is to add IMapper mapper as a parameter to Configure() - the parameter list is dependency-injected so you can reference any service registered in ConfigureServices()

public void Configure(IApplicationBuilder app, ... , IMapper mapper)
{
  ...
        mapper.ConfigurationProvider.AssertConfigurationIsValid();
}

Works exactly as expected.

Answer 2

The recommended approach (see JBogard's response) is to move this test into a unit test:

public class MappingTests
{
    private readonly IMapper _sut;

    public MappingTests() => _sut = new MapperConfiguration(cfg => { cfg.AddProfile<MyAutomapperProfile>(); }).CreateMapper();

    [Fact]
    public void All_mappings_should_be_setup_correctly() => _sut.ConfigurationProvider.AssertConfigurationIsValid();
}