db-coalesce-tests.cs

public class Contract
{   
	public int Id { get; set; }
	public string Url { get; set; }
}

public class ModelContext : DbContext
{
	public static readonly ILoggerFactory DebugLoggerFactory
		= LoggerFactory.Create(builder => { builder.AddDebug(); });

	public virtual DbSet<Contract> ContractType { get; set; }

	public ModelContext(DbContextOptions<ModelContext> options) : base(options) {}

	protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
	{
		base.OnConfiguring(optionsBuilder);

		optionsBuilder
			.UseLoggerFactory(DebugLoggerFactory)
			.EnableSensitiveDataLogging();
	}

	protected override void OnModelCreating(ModelBuilder modelBuilder)
	{
		base.OnModelCreating(modelBuilder);

		modelBuilder.Entity<Contract>(entity =>
		{
			entity.ToTable("CONTRACT");

			entity.Property(e => e.Id).HasColumnName("ID");

			entity.Property(e => e.Url)
				.HasColumnName("URL")
				.HasColumnType("VARCHAR2(100)");
		});
	}
}

public class DbContextTests
{
	[Test]
	public void NonUnicode_Coalesce()
	{
		using var context = new ModelContext(new DbContextOptionsBuilder<ModelContext>()
			.UseOracle("my_connection_string")
			.Options);

		string sqlQuery = context.ContractType
			.Select(x => x.Url ?? "-")
			.FirstOrDefault();

		Assert.Pass();
	}
}