Add version check for Firebird 5 in union tests

Author: niekschoemaker

src/FirebirdSql.EntityFrameworkCore.Firebird.FunctionalTests/Query/NorthwindSetOperationsQueryFbTest.cs

@@ -18,6 +18,7 @@
 using System;
 using System.Threading.Tasks;
 using FirebirdSql.EntityFrameworkCore.Firebird.FunctionalTests.Helpers;
+using FirebirdSql.EntityFrameworkCore.Firebird.FunctionalTests.TestUtilities;
 using Microsoft.EntityFrameworkCore.Query;
 using Microsoft.EntityFrameworkCore.TestUtilities;
 using Xunit;
@@ -37,11 +38,13 @@ public override Task Union_Select_scalar(bool async)
 		return base.Union_Select_scalar(async);
 	}
 
-	// Not supported on FB 3 and 4
-	[NotSupportedOnFirebirdTheory]
+	[Theory]
 	[MemberData(nameof(IsAsyncData))]
 	public override Task Union_inside_Concat(bool async)
 	{
+		var fbTestStore = (FbTestStore)Fixture.TestStore;
+		if (fbTestStore.ServerLessThan5())
+			return Task.CompletedTask;
 		return base.Union_inside_Concat(async);
 	}
 

src/FirebirdSql.EntityFrameworkCore.Firebird.FunctionalTests/TestUtilities/FbTestStore.cs

@@ -43,6 +43,8 @@ public FbTestStore(string name, bool shared)
 	public Version ServerVersion { get; private set; }
 	public bool ServerLessThan4() => ServerVersion < new Version(4, 0, 0, 0);
 
+	public bool ServerLessThan5() => ServerVersion < new Version(5, 0, 0, 0);
+
 	protected override async Task InitializeAsync(Func<DbContext> createContext, Func<DbContext, Task> seed, Func<DbContext, Task> clean)
 	{
 		if (Connection.State != ConnectionState.Closed)