public void SelectSingleVariable()
{
const string sql = "SELECT * FROM system.vars WHERE var = 'a'";
var query = (SqlQueryExpression)SqlExpression.Parse(sql);
var result = AdminQuery.Select(query);
Assert.IsNotNull(result);
Row row = null;
Assert.DoesNotThrow(() => row = result.Fetch(FetchDirection.Next, -1));
Assert.IsNotNull(row);
var name = row.GetValue("var");
var type = row.GetValue("type");
var value = row.GetValue("value");
var constant = row.GetValue("constant");
Assert.IsFalse(Field.IsNullField(name));
Assert.IsFalse(Field.IsNullField(type));
Assert.IsTrue(value.IsNull);
Assert.IsFalse(Field.IsNullField(constant));
}