Consider using sp_executesql according to https://learn.microsoft.com/en-US/troubleshoot/sql/admin/pass-variable-linked-server-query:
EXEC TestServer.master.dbo.sp_executesql N'SELECT * FROM MyDatabase.dbo.T2 WHERE Column1 = @Test1 and Column2 != ''''',
N'@Test1 nvarchar(10)', @Test1