How to set up the DbContext in xUnit test project properly?

Question

I have the following code to set up DBContext in the .Net core 2.0 console program and it's injected to the constructor of the main application class.

    IConfigurationRoot configuration = GetConfiguration();
    services.AddSingleton(configuration);
    Conn = configuration.GetConnectionString("ConnStr1");

    services.AddDbContext<MyDbContext>(o => o.UseSqlServer(Conn));

Now I created a xUnit test class and need to initialize the same DbContext for testing.

    context = new MyDbContext(new DbContextOptions<MyDbContext>());

It gets the error of the parameter connectionString cannot be null. How to set up the DbContext in test project properly?

Mercaptide

You just need to set options for it. As example this option are used to store db in the memory: var optionsBuilder = new DbContextOptionsBuilder<MyDbContext>(); optionsBuilder.UseInMemoryDatabase(); var context = new MyDbContext(optionsBuilder.Options); – Eyrir

Answer 1

I found a way to do it.

var dbOption = new DbContextOptionsBuilder<MyDbContext>()
    .UseSqlServer("....")
    .Options;

Mercaptide

For others looking, the other solutions are slightly more complete in that they initialize the context too! – Burnell

Answer 2

The George Alexandria's solutions work for me:

var optionsBuilder = new DbContextOptionsBuilder<MyDbContext>();
optionsBuilder.UseInMemoryDatabase(); 
var context = new MyDbContext(optionsBuilder.Options);

The UseInMemoryDatabase extension method is included in Microsoft.EntityFrameworkCore.InMemory

Airspeed

For those who use this more complete method, don't forget to either use 'context.dispose()' or a using bracket i.e. using (var context = new MyDbContext(optionsBuilder.Options)){ // Your code here}. – Saphead

Do you have configuration using fluent API? It seems the ModelBuilder is no available for the OnModelCreating(ModelBuilder modelBuilder) beucase it is supplied with DI from ASP.Net. Is there a way to supply the ModelBuilder for the DBContext in a testing project? – Scalage

Answer 3

EF 2.0 requires that all in-memory database are named, so be sure to name it like so:

var optionsBuilder = new DbContextOptionsBuilder<MyDbContext>();
optionsBuilder.UseInMemoryDatabase("MyInMemoryDatabseName"); 
var context = new MyDbContext(optionsBuilder.Options);

Gertrudegertrudis