using System;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using System.Linq.Expressions;

using Xunit;

namespace LinqStudy.Test.LinqToObject
{
    public class TakeTest
    {
        [Fact]
        public void TakeWhile_Test()
        {
            List<Person> customers = new List<Person> {
                new Person { Id=1,Name="woody1"},
                new Person { Id=2,Name="woody2"},
                new Person { Id=3,Name="woody3"},
                new Person { Id=4,Name="woody1"}
            };

            var person = customers.TakeWhile(c => c.Name.StartsWith("woody1"));

            //因为匹配第二项时，结果是False，程序返回，不再进行下次迭代，所以返回集合中只有第一项。
            Assert.Equal(customers.FindAll(q => q.Id == 1), person);        }

        [Fact]
        public void Test()
        {
            List<Person> customers = new List<Person> {
                new Person { Id=1,Name="woody1"},
                new Person { Id=2,Name="woody2"},
                new Person { Id=3,Name="woody3"},
                new Person { Id=4,Name="woody1"}
            };

            var person = customers.TakeWhile(c => c.Name.StartsWith("woody2"));

            //因为匹配第一项时，结果是False，程序直接返回，不再进行下次迭代，所以返回空集合。
            Assert.Empty(person);
        }
    }
}