단위 테스트 - 6장 단위 테스트 스타일

1. AuditManager

public class AuditManager
{
    private readonly int _maxEntriesPerFile;
    private readonly string _directoryName;

    public AuditManager(int maxEntriesPerFile, string directoryName)
    {
        _maxEntriesPerFile = maxEntriesPerFile;
        _directoryName = directoryName;
    }

    public void AddRecord(string visitoirName, DataTime timeOfVisit)
    {
        string[] filePaths = Directory.GetFiles(_directoryName);
        (int index, string path)[] sorted = SortByIndex(filePaths);

        string newRecord = visitorNAme + ‘;’ + timeOfVisit;

        if (sorted.Length == 0)
        {
            string newFile = Path.Combine(_directoryName, “audit_1.txt”)
            File.WriteAllText(newFile, newRecord);
            return;
        }

        (int currentFileIndex, string currnetFilePath) = sorted.Last();
        List<string> lines = File.ReadAllLines(currentFilePath).ToList();
        
        if (lines.Count < _maxEntriesPerFile)
        {
            lines.Add(newRecord);
            string newContent = string.Join("\r\n", lines);
            File.WriteAllTExt(currentFilePAth, newContent);
        }
        else
        {
            int newIndex = currentFileIndex + 1;
            string newName = $"audit_{newIndex}.txt";
            string newFile = Path.Combine(_directoryName, newName);
            File.WriteAllText(newFile, newRecord);
        }
    }
}

2-1. AuditManager 생성자를 통한 파일 시스템의 명시적 주입

public class AuditManager
{
    private readonly int _maxEntriesPerFile;
    private readonly string _directoryName;
    private readonly IFileSystem _fileSystem;

    public AuditManager(
        int maxEntriesPerFile,
        string directoryName,
        IfFileSystem fileSystem)
    {
        _maxEntriesPerFile = maxEntriesPerFile;
        _directoryName = directoryName;
        _fileSystem = fileSystem;
    }
}

2-2. 새로운 iFileSystem 인터페이스 사용

public void AddRecord(string visitoirName, DataTime timeOfVisit)
{
    string[] filePaths = _fileSystem.GetFiles(_directoryName);
    (int index, string path)[] sorted = SortByIndex(filePaths);

    string newRecord = visitorNAme + ‘;’ + timeOfVisit;

    if (sorted.Length == 0)
    {
        string newFile = Path.Combine(_directoryName, “audit_1.txt”)
        _fileSystem.WriteAllText(newFile, newRecord);
        return;
    }

    (int currentFileIndex, string currnetFilePath) = sorted.Last();
    List<string> lines = _fileSystem.ReadAllLines(currentFilePath).ToList();

    if (lines.Count < _maxEntriesPerFile)
    {
        lines.Add(newRecord);
        string newContent = string.Join("\r\n", lines);
        _fileSystem.WriteAllTExt(currentFilePAth, newContent);
    }
    else
    {
        int newIndex = currentFileIndex + 1;
        string newName = $"audit_{newIndex}.txt";
        string newFile = Path.Combine(_directoryName, newName);
        _fileSystem.WriteAllText(newFile, newRecord);
    }
}

2-3. 목을 이용한 감사 시스템의 동작 확인

[Fact]
public void A_new_file_is_created_when_the_current_file_overflows()
{
    var fileSystemMock = new Mock<IFileSystem>();
    fileSystemMock
        .Setup(x => x.GetFiles("audits"))
        .Returns(new String[]
        {
            @"audits\audit_1.txt",
            @"audits\audit_2.txt"
        });
    fileSystemMock
        .Setup(x => x.ReadAllLines(@"audits\audit_2.txt"))
        .Returns(new List<string>
        {
            "Peter; 2019-04-06T16:30:00",
            "Jane; 2019-04-06T16:40:00",
            "Jack; 2019-04-06T17:00:00",
        });
    var sut = new AuditManager(3, "audits", fileSystemMock.Object);
    
    sut.AddRecord("Alice", DateTime.Parse("2019-04-16T18:00:00"));
    
    fileSystemMock.Verify(x => x.WriteAllText(
        @"audits\audit_3.txt",
        "Alice;2019-04-06T18:00:00"));
}

3-1. FileContent

public class FileContent
{
    public readonly string FileName;
    publllic readonly string[] Lines;
    
    publlic FileContent(string fileName, string[] lines)
    {
        FileName = fileName;
        Lines = lines;
    }
}

3-2. FileUpdate

public class FileContent
{
    public readonly string FileName;
    publllic readonly string NewContent;
    
    publlic FileContent(string fileName, string newContent)
    {
        FileName = fileName;
        NewContent = newContent;
    }
}

3-3. Persister

public class Persister
{
    public FileContent[] ReadDirectory(string direcctoryName)
    {
        return Directory
            .GetFiles(directoryName)
            .Select(x => new FileContent(
                Path.GetFileName(x)),
                File.ReadAllLines())
            .ToArray();
    }
    
    public void ApplyUpdate(string directoryName, FileUpdate updadte)
    {
        string filePath = Path.Combine(directoryName, update.FileName);
        File.WriteAllText(filePath, update.NewContent);
    }
}

3. 리팩터링 후의 AuditManager

public class AuditManager
{
    private readonly int _maxEntriesPerFile;
    
    public AuditManager(int maxEntriesPerFile)
    {
        _maxEntriesPerFile = maxEntriesPerFile;
    }
    
    public FileUpdate AddRecord(
        FileContent[] files,
        string visitorName,
        DateTime tiemOfVisit)
    {
        (int index, FileContent file)[] sorted = SortByIndex(files);

        string newRecord = visitorNAme + ‘;’ + timeOfVisit;

        if (sorted.Length == 0)
        {
            return new FileUpdate(
                "audit_1.txt", newRecord);
        }

        (int currentFileIndex, FileContent currentFile) = sorted.Last();
        List<string> lines = currentFile.Lines.ToList();

        if (lines.Count < _maxEntriesPerFile)
        {
            lines.Add(newRecord);
            string newContent = string.Join("\r\n", lines);
            return new FileUpdate(
                currentFile.FileName, newContent);
        }
        else
        {
            int newIndex = currentFileIndex + 1;
            string newName = $"audit_{newIndex}.txt";
            return new FileUpdate(
                newName, newRecord);
        }
    }
}

4. Application Service

public class ApplicationService
{
    private readonly string _directoryName;
    private readonly AuditManager _auditManager;
    private readonly Persister _persister;
    
    public ApplicationService(
        string directoryName, int maxEntriesPerFile)
    {
        _directoryName = directoryName;
        _auditManager = new AuditManager(maxEntiresPerFile);
        _persister = new Persister();
    }
    
    public void AddRecord(string visitorName, DateTime timeOfVisit)
    {
        FileContent[] files = _persister.ReadDirectory(_directoryName);
        FileUpdate update = _auditManager.AddRecord(
            files, visitorName, timeOfVisit);
        _persister.ApplyUpdate(_directoryNAme, update);
    }
}

5. 목 없이 작성된 테스트

[Fact]
public void A_new_file_is_created_when_the_current_file_overflows()
{
    var sut = new AuditManager(3);
    var files = new FileContent[]
    {
        new FileContent("audit_1".txt, new String[0]),
        new FileContent("audit_2".txt, new String[]
        {
            "Peter; 2019-04-06T16:30:00",
            "Jane; 2019-04-06T16:40:00",
            "Jack; 2019-04-06T17:00:00"
        })
    };
    
    FileUpdate update = sut.AddRecord(
        files, "Alice", DateTime.parse("2019-04-06T18:00:00"));
    
    Assert.Equal("audit_3.txt", update.FileName);
    Assert.Equal("Alice;2019-04-06T18:00:00", update.NewContent);
}