CsvFieldsSaver + Tests

CsvFieldsSaver.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Restuta;
using System.Text;

namespace Restuta.FieldSavers
{
    /// <summary>
    /// Writes provided list of values to CSV file.
    /// </summary>
    public class CsvFieldsSaver : IFormFieldsSaver
    {
        private readonly TextWriter fileWriter;
        private const string Comma = ",";
        private static readonly string LineBreak = Environment.NewLine;
        private const string DoubleQuote = @"""";

        /// <summary>
        /// Initializes a new instance of the <see cref="CsvFieldsSaver"/> class.
        /// </summary>
        /// <param name="fileWriter">The file writer.</param>
        public CsvFieldsSaver(TextWriter fileWriter)
        {
            fileWriter.ThrowIfNull("fileWriter");
            this.fileWriter = fileWriter;
        }

        /// <summary>
        /// Saves form values in CSV format using provided <see cref="TextWriter"/>.
        /// </summary>
        /// <param name="values"></param>
        /// <returns></returns>
        public void Save(IEnumerable<FormItem> values)
        {
            values.ThrowIfNull("values");

            this.Write(values.Select(x => x.DisplayName));
            this.fileWriter.Write(LineBreak);
            this.Write(values.Select(x => x.Value));
        }

        /// <summary>
        /// Writes the specified items using <see cref="TextWriter"/>.
        /// </summary>
        /// <param name="items">The items.</param>
        private void Write(IEnumerable<string> items)
        {
            List<string> enclosedItems = EncloseItemsAccordingToCsvStandard(items);

            this.fileWriter.Write(string.Join(",", enclosedItems.ToArray()));
        }

        private static List<string> EncloseItemsAccordingToCsvStandard(IEnumerable<string> items)
        {
            List<string> itemsCopy = new List<string>(items.Count());
            
            foreach (var item in items)
            {
                string quotedItem = null;

                if (item == null)
                {
                    itemsCopy.Add(string.Empty);
                    continue;
                }

                if (item.Contains(DoubleQuote))
                {
                    quotedItem = QuoteEachDoubleQuote(item);
                }

                if (item.Contains(Comma) || item.Contains(LineBreak) || item.Contains(DoubleQuote) 
                    || HasLeadingOrTrailingSpaces(item))
                {
                    string enclosedItem = string.Format("\"{0}\"", quotedItem ?? item);
                    itemsCopy.Add(enclosedItem);
                }
                else
                {
                    itemsCopy.Add(item);
                }
            }
            return itemsCopy;
        }

        private static string QuoteEachDoubleQuote(string item)
        {
            const string TwoDoubleQuotes = "\"\"";
            return item.Replace(DoubleQuote, TwoDoubleQuotes);
        }

        private static bool HasLeadingOrTrailingSpaces(string item)
        {
            return item.Length != item.Trim().Length;
        }
    }


}

CsvFieldsSaverFixture.cs

using System;
using System.Collections.Generic;
using System.IO;
using NUnit.Framework;
using Rhino.Mocks;
using System.Linq;
using Restuta.FieldSavers;

// ReSharper disable PublicMembersMustHaveComments
// ReSharper disable IdentifierWordIsNotInDictionary
namespace Restuta.Tests.FieldSavers
{
    [TestFixture]
    public class CsvFieldsSaverFixture
    {
        private TextWriter textWriter;

        [SetUp]
        public void SetUp()
        {
            this.textWriter = MockRepository.GenerateMock<TextWriter>();
        }

        [Test]
        public void Ctor_ShouldNotThrow()

        {
            var csvWriter = new CsvFieldsSaver(this.textWriter);
        }

        [Test]
        public void Ctor_NullPassed_ShouldThrow()
        {
            Assert.Throws<ArgumentNullException>(() => new CsvFieldsSaver(null));
        }

        [Test]
        public void Save_NullPassed_ShouldThrow()
        {
            Assert.Throws<ArgumentNullException>(() => new CsvFieldsSaver(textWriter).Save(null));
        }

        [Test]
        public void Save_SeveralItemsPassed_ShouldWriteToWriter()
        {
            //arrange
            var fileWriter = new FileWriter(new StreamWriter(new MemoryStream()));
            var csvWriter = new CsvFieldsSaver(fileWriter);
            List<FormItem> items = this.GetFormItems("item1", "item2");

            //act
            csvWriter.Save(items);

            //assert
            
            MemoryStream memoryStream = (MemoryStream)fileWriter.StreamWriter.BaseStream;
            memoryStream.Position = 0;

            string result = this.GetResult(memoryStream);

            Assert.That(result, Is.EqualTo(@"," + Environment.NewLine + @"item1,item2"));
        }

        [Test]
        public void Save_ItemWithComma_ShouldBeEnclosedWithDoubleQuotedCharacter()
        {
            //arrange
            var memoryStream = new MemoryStream();
            var fileWriter = new FileWriter(new StreamWriter(memoryStream));
            var csvWriter = new CsvFieldsSaver(fileWriter);
            List<FormItem> items = this.GetFormItems("ite,m1", "item2");

            //act
            csvWriter.Save(items);

            //assert
            string result = this.GetResult(memoryStream);
            Assert.That(result, Is.EqualTo(@"," + Environment.NewLine + @"""ite,m1"",item2"));
        }

        [Test]
        public void Save_EmptyItem_ShouldWriteEmpty()
        {
            //arrange
            var memoryStream = new MemoryStream();
            var fileWriter = new FileWriter(new StreamWriter(memoryStream));
            var csvWriter = new CsvFieldsSaver(fileWriter);
            List<FormItem> items = this.GetFormItems("item1", string.Empty);

            //act
            csvWriter.Save(items);

            //assert
            string result = this.GetResult(memoryStream);
            Assert.That(result, Is.EqualTo(",\r\nitem1,"));
        }

        [Test]
        public void Save_ItemsWithDoubleQuotes_ShouldBeEnclosedToDoubleQuotesAndQuotedEachDoubleQuote()
        {
            //arrange
            var memoryStream = new MemoryStream();
            var fileWriter = new FileWriter(new StreamWriter(memoryStream));
            var csvWriter = new CsvFieldsSaver(fileWriter);
            List<FormItem> items = this.GetFormItems(@"it""e""m1", "item2");

            //act
            csvWriter.Save(items);

            //assert
            string result = this.GetResult(memoryStream);
            Assert.That(result, Is.EqualTo(@"," + Environment.NewLine + @"""it""""e""""m1"",item2"));
        }

        [Test]
        public void Save_ItemsWithLeadingOrTrailingSpaces_MustBeEnclosedWithDoubleQuotes()
        {
            //arrange
            var memoryStream = new MemoryStream();
            var fileWriter = new FileWriter(new StreamWriter(memoryStream));
            var csvWriter = new CsvFieldsSaver(fileWriter);
            List<FormItem> items = this.GetFormItems(@" item1 ", "item2");

            //act
            csvWriter.Save(items);

            //assert
            string result = this.GetResult(memoryStream);
            Assert.That(result, Is.EqualTo(@"," + Environment.NewLine + @""" item1 "",item2"));
        }

        [Test]
        public void Save_ItemsWithEmbeddedLineBrakes_MustBeEnclosedWithDoubleQuotes()
        {
            //arrange
            var memoryStream = new MemoryStream();
            var fileWriter = new FileWriter(new StreamWriter(memoryStream));
            var csvWriter = new CsvFieldsSaver(fileWriter);
            List<FormItem> items = this.GetFormItems(@"ite" + Environment.NewLine + @"m1", "item2");

            //act
            csvWriter.Save(items);

            //assert
            string result = this.GetResult(memoryStream);
            Assert.That(result, Is.EqualTo(@"," + Environment.NewLine + @"""ite" + Environment.NewLine + @"m1"",item2"));
        }

        [Test]
        public void Save_ShouldWriteItemsWithHeaders()
        {
            //arrange
            var memoryStream = new MemoryStream();
            var fileWriter = new FileWriter(new StreamWriter(memoryStream));
            var csvWriter = new CsvFieldsSaver(fileWriter);
            List<FormItem> items = new List<FormItem>
            {
               new FormItem { Value = "item1", DisplayName = "HeaderItem1"}, 
               new FormItem { Value = "item2", DisplayName = "HeaderItem2"}
            };

            //act
            csvWriter.Save(items);

            //assert
            string result = this.GetResult(memoryStream);

            Assert.That(result, Is.EqualTo(@"HeaderItem1,HeaderItem2" + Environment.NewLine + @"item1,item2"));
        }

        [Test]
        public void Save_ItemsHasNullDisplayNames_ShouldWriteAsEmptyStrings()
        {
            //arrange
            var memoryStream = new MemoryStream();
            var fileWriter = new FileWriter(new StreamWriter(memoryStream));
            var csvWriter = new CsvFieldsSaver(fileWriter);
            List<FormItem> items = new List<FormItem>
            {
               new FormItem { Value = "item1", DisplayName = null}, 
               new FormItem { Value = "item2", DisplayName = null}
            };

            //act
            csvWriter.Save(items);

            //assert
            string result = this.GetResult(memoryStream);
            Assert.That(result, Is.EqualTo(@"," + Environment.NewLine + @"item1,item2"));
        }

        [Test]
        public void Save_ItemsWithCommasInDisplayName_ShouldBeQuoted()
        {
            //arrange
            var memoryStream = new MemoryStream();
            var fileWriter = new FileWriter(new StreamWriter(memoryStream));
            var csvWriter = new CsvFieldsSaver(fileWriter);
            List<FormItem> items = new List<FormItem>
            {
               new FormItem { Value = "item1", DisplayName = "Header,Item1"}, 
               new FormItem { Value = "item2", DisplayName = "HeaderItem2"}
            };

            //act
            csvWriter.Save(items);

            //assert
            string result = this.GetResult(memoryStream);

            Assert.That(result, Is.EqualTo(@"""Header,Item1"",HeaderItem2"+ Environment.NewLine +"item1,item2"));
        }

        #region private members
        private string GetResult(MemoryStream memoryStream)
        {
            string result = null;
            memoryStream.Position = 0;
            using (var reader = new StreamReader(memoryStream))
            {
                result = reader.ReadToEnd();
            }
            return result;
        }

        private List<FormItem> GetFormItems(params string[] items)
        {
            var formItems = new List<FormItem>();
            formItems.AddRange(items.Select(x => new FormItem {Value = x}));
            return formItems;
        }

        #endregion
        
    }
}

// ReSharper restore PublicMembersMustHaveComments
// ReSharper restore IdentifierWordIsNotInDictionary