test: decimal mapping (22,9 & 30,10)

Author: LiamHamsters

src/EFCore.Ydb/test/EntityFrameworkCore.Ydb.FunctionalTests/Query/DecimalParameterYdbTest.cs

@@ -1,4 +1,7 @@
+using EntityFrameworkCore.Ydb.Extensions;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Storage;
 using Xunit;
 
 namespace EntityFrameworkCore.Ydb.FunctionalTests.Query;
@@ -44,10 +47,52 @@ public async Task Decimal_out_of_range_bubbles_up()
         await using var ctx = Fixture.CreateContext();
         await ctx.Database.EnsureCreatedAsync();
 
-        var tooBig = new ItemExplicit { Price = 10_000_000_000_000m }; // 14 целых цифр -> вне 22,9
+        var tooBig = new ItemExplicit { Price = 10_000_000_000_000m };
         ctx.Add(tooBig);
 
         var ex = await Assert.ThrowsAsync<DbUpdateException>(() => ctx.SaveChangesAsync());
         Assert.Contains("Decimal", ex.InnerException?.Message ?? "");
     }
+
+    [Fact]
+    public void Type_mapping_default_decimal_is_22_9()
+    {
+        using var ctx = Fixture.CreateContext();
+        var tms = ctx.GetService<IRelationalTypeMappingSource>();
+        var mapping = tms.FindMapping(typeof(decimal))!;
+        Assert.Equal("Decimal(22, 9)", mapping.StoreType);
+    }
+
+    [Fact]
+    public void Type_mapping_custom_decimal_is_30_10()
+    {
+        var opts = new DbContextOptionsBuilder<MappingOnlyContext>()
+            .UseYdb("")
+            .Options;
+
+        using var ctx = new MappingOnlyContext(opts);
+        var tms = ctx.GetService<IRelationalTypeMappingSource>();
+
+        var et = ctx.Model.FindEntityType(typeof(MappingEntity))!;
+        var prop = et.FindProperty(nameof(MappingEntity.Price))!;
+        var mapping = tms.FindMapping(prop)!;
+
+        Assert.Equal("Decimal(30, 10)", mapping.StoreType);
+    }
+
+    private sealed class MappingOnlyContext(DbContextOptions<MappingOnlyContext> options) : DbContext(options)
+    {
+        protected override void OnModelCreating(ModelBuilder b)
+            => b.Entity<MappingEntity>(e =>
+               {
+                   e.HasKey(x => x.Id);
+                   e.Property(x => x.Price).HasPrecision(30, 10);
+               });
+    }
+
+    private sealed class MappingEntity
+    {
+        public int Id { get; set; }
+        public decimal Price { get; set; }
+    }
 }