How do I setup a list of test organizations with my new DBContext? - entity-framework

Question

I have an application with uses multiple contexts for EF, some are code first, some server first, and all are dynamic.
I have a class that I call to get these contexts in my app.
Each context implements an interface such as:
public interface IDatabaseContextSwitcher
{
IVGSContext GetDatabase(string organization);
IVGSContext GetDatabase(Guid organizationGuid, string email);
IVGSServerConn GetServerDatabase(string databaseName);
IAuthContext GetAuthorizationDatabase();
}
I therefore has a class that implments the instances of these interfaces in the application. (VGSContext, VGSServerConn, and AuthContext).
I am trying to test these in my test project. I have made new classes from the interfaces with the plan to plug in some DbSets into these new classes and then test that my controllers do the correct thing.
However, I can't seem to figure out how to initialize the DBSets.
For example the following dies on Add:
public AuthContextForTesting()
{
Organizations.Add(new Organization()
{OrganizationName = "Test1", PK_Organization = Guid.Parse("34CE4F83-B3C9-421B-B1F3-42BBCDA9A004")});
var cnt = Organizations.Count();
}
public DbSet<Organization> Organizations { get; set; }
I tried to initialize the DBSet with:
Organizations=new DbSet();
But it gives an error that this is not allowed due to permissions.
How do I set up my initial dbsets in code for my tests?

Answer 1

To be able to do this, you first have to derive a class from DBSet. Sadly, my app uses both Core EF and EF 6 so I had to create 2 classes.
EF 6 Class
public class FakeDbSet<T> : System.Data.Entity.DbSet<T>, IDbSet<T> where T : class
{
List<T> _data;
public FakeDbSet()
{
_data = new List<T>();
}
public override T Find(params object[] keyValues)
{
throw new NotImplementedException("Derive from FakeDbSet<T> and override Find");
}
public override T Add(T item)
{
_data.Add(item);
return item;
}
public override T Remove(T item)
{
_data.Remove(item);
return item;
}
public override T Attach(T item)
{
return null;
}
public T Detach(T item)
{
_data.Remove(item);
return item;
}
public override T Create()
{
return Activator.CreateInstance<T>();
}
public TDerivedEntity Create<TDerivedEntity>() where TDerivedEntity : class, T
{
return Activator.CreateInstance<TDerivedEntity>();
}
public List<T> Local
{
get { return _data; }
}
public override IEnumerable<T> AddRange(IEnumerable<T> entities)
{
_data.AddRange(entities);
return _data;
}
public override IEnumerable<T> RemoveRange(IEnumerable<T> entities)
{
for (int i = entities.Count() - 1; i >= 0; i--)
{
T entity = entities.ElementAt(i);
if (_data.Contains(entity))
{
Remove(entity);
}
}
return this;
}
Type IQueryable.ElementType
{
get { return _data.AsQueryable().ElementType; }
}
System.Linq.Expressions.Expression IQueryable.Expression
{
get { return _data.AsQueryable().Expression; }
}
IQueryProvider IQueryable.Provider
{
get { return _data.AsQueryable().Provider; }
}
IEnumerator IEnumerable.GetEnumerator()
{
return _data.GetEnumerator();
}
IEnumerator<T> IEnumerable<T>.GetEnumerator()
{
return _data.GetEnumerator();
}
}
The EF Core had to include some interfaces to work.
public class FakeCoreDbSet<T> : Microsoft.EntityFrameworkCore.DbSet<T> , IQueryable, IEnumerable<T> where T : class
{
List<T> _data;
public FakeCoreDbSet()
{
_data = new List<T>();
}
public override T Find(params object[] keyValues)
{
throw new NotImplementedException("Derive from FakeDbSet<T> and override Find");
}
public override EntityEntry<T> Add(T item)
{
_data.Add(item);
//return item;
return null;
}
public override EntityEntry<T> Remove(T item)
{
_data.Remove(item);
//return item;
return null;
}
public override EntityEntry<T> Attach(T item)
{
return null;
}
public T Detach(T item)
{
_data.Remove(item);
return item;
}
public IList GetList()
{
return _data.ToList();
}
//public override T Create()
//{
// return Activator.CreateInstance<T>();
//}
public TDerivedEntity Create<TDerivedEntity>() where TDerivedEntity : class, T
{
return Activator.CreateInstance<TDerivedEntity>();
}
public List<T> Local
{
get { return _data; }
}
public override void AddRange(IEnumerable<T> entities)
{
_data.AddRange(entities);
//return _data;
}
public override void RemoveRange(IEnumerable<T> entities)
{
for (int i = entities.Count() - 1; i >= 0; i--)
{
T entity = entities.ElementAt(i);
if (_data.Contains(entity))
{
Remove(entity);
}
}
// this;
}
Type IQueryable.ElementType
{
get { return _data.AsQueryable().ElementType; }
}
System.Linq.Expressions.Expression IQueryable.Expression
{
get { return _data.AsQueryable().Expression; }
}
IQueryProvider IQueryable.Provider
{
get { return _data.AsQueryable().Provider; }
}
IEnumerator IEnumerable.GetEnumerator()
{
return _data.GetEnumerator();
}
IEnumerator<T> IEnumerable<T>.GetEnumerator()
{
return _data.GetEnumerator();
}
}
Once these were created I could use MockObjects to get to them.
Note _dbContextSwitcher is the class created with a Moq that calls the different databases.
var vgsdatabase = new Mock<IVGSContext>();
var settings=new FakeCoreDbSet<Setting>();
settings.Add(new Setting()
{
SettingID = "OrgPrivacy",
PK_Setting = Guid.NewGuid(),
UserID = "",
Value = "No"
});
vgsdatabase.Setup(s => s.Setting).Returns(settings);
_dbcontextSwitcher.Setup(s => s.GetDatabase(It.IsAny<string>())).Returns(vgsdatabase.Object);