public void Avg()
{
Person person = new Person();
Exception ex = Assert.Throws <InvalidOperationException>(() => SqlExp.Avg(person.Salary));
Assert.Equal("Only for expressions.", ex.Message);
}
public void Avg()
{
Person person = null;
IFunction func = (IFunction)sql.Val(() => SqlExp.Avg(person.Salary));
QueryResult result = engine.Compile(func);
Assert.Equal("AVG(`person`.`Salary`)", result.Sql);
Assert.Equal(new Dictionary <string, object>(), result.Parameters);
}