Dbcontext not able to migrate because schema does not exist? - postgresql

Question

I am currently writing some integrations test which affect the database just in a different schema.
I am following this guide
https://www.thinktecture.com/en/entity-framework-core/isolation-of-integration-tests-in-2-1/
My problem is with this abstract class used for creating DbContext?
public abstract class IntegrationTestsBase<T> : IDisposable
where T : DbContext
{
private readonly string _schema;
private readonly string _historyTableName;
private readonly DbContextOptions<T> _options;
protected T DbContext { get; }
protected IntegrationTestsBase()
{
_schema = Guid.NewGuid().ToString("N");
_historyTableName = "__EFMigrationsHistory";
_options = CreateOptions();
DbContext = CreateContext();
DbContext.Database.Migrate();
}
protected abstract T CreateContext(DbContextOptions<T> options,
IDbContextSchema schema);
protected T CreateContext()
{
return CreateContext(_options, new DbContextSchema(_schema));
}
private DbContextOptions<T> CreateOptions()
{
return new DbContextOptionsBuilder<T>()
.UseNpgsql($"Server=(local);Database=Demo;...",
builder => builder.MigrationsHistoryTable(_historyTableName, _schema))
.ReplaceService<IMigrationsAssembly, DbSchemaAwareMigrationAssembly>()
.ReplaceService<IModelCacheKeyFactory, DbSchemaAwareModelCacheKeyFactory>()
.Options;
}
public void Dispose()
{
DbContext.GetService<IMigrator>().Migrate("0");
DbContext.Database.ExecuteSqlCommand(
(string)$"DROP TABLE [{_schema}].[{_historyTableName}]");
DbContext.Database.ExecuteSqlCommand((string)$"DROP SCHEMA [{_schema}]");
DbContext?.Dispose();
}
}
DbContext is being created, but once the migrations is being called i get an error stating that the schema, does not exist?
which I am not sure why because i in my ensure the in my configuration
public class SchemaContext : DbContext, IDbContextSchema
{
public virtual DbSet<Schema>? SchemaModel { get; set; }
public SchemaContext()
{
}
public SchemaContext(DbContextOptions<SchemaContext> options, IDbContextSchema schema = null)
: base(options)
{
Schema = schema.Schema;
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.HasDefaultSchema(Schema);
//base.OnModelCreating(modelBuilder);
modelBuilder.ApplyConfigurationsFromAssembly(Assembly.GetExecutingAssembly());
}
public string Schema { get; }
}
I would assume that modelBuilder.HasDefaultSchema(Schema); would have created the schema?
which does not seem to be case, hence migration fails? what am I missing? why is the schema not being created in the actual database?

Answer 1

In your could you are configure Context with method - UseSqlServer which is used only for MS SQL, you have to use Npgsql.EntityFrameworkCore.PostgreSql package and configure you context with UseNpgsql extension method:
.UseNpgsql("Host=localhost;Port=5432;Database=my_db;Username=postgres;Password=password");