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Copy pathAnalysisTests.cs
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248 lines (210 loc) · 8.5 KB
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using System;
using System.IO;
using System.IO.Compression;
using System.Linq;
using SmartFileKit.Analysis;
using SmartFileKit.Domain;
using Xunit;
namespace SmartFileKit.Tests
{
public class AnalysisTests
{
[Fact]
public void Analyze_EmptyStream_ShouldReturnEmptyFileIssue()
{
using (var stream = new MemoryStream(Array.Empty<byte>()))
{
var report = FileAnalyzer.Analyze(stream, "empty.txt");
Assert.False(report.IsSafe);
Assert.True(report.IsSuspicious);
Assert.Equal(10, report.RiskScore);
Assert.Equal(FileRiskLevel.Safe, report.RiskLevel);
Assert.Single(report.Issues);
Assert.Equal(IssueType.EmptyFile, report.Issues[0].Type);
}
}
[Fact]
public void Analyze_SignatureMismatch_ExeRenamedToPdf_ShouldBeHighRisk()
{
byte[] buffer = new byte[100];
buffer[0] = 0x4D;
buffer[1] = 0x5A;
using (var stream = new MemoryStream(buffer))
{
var report = FileAnalyzer.Analyze(stream, "invoice.pdf");
Assert.False(report.IsSafe);
Assert.True(report.IsSuspicious);
Assert.True(report.RiskScore >= 90);
Assert.Equal(FileRiskLevel.High, report.RiskLevel);
Assert.Contains(report.Issues, i => i.Type == IssueType.SignatureMismatch);
}
}
[Fact]
public void Analyze_RawExecutableUpload_ShouldBeMediumRiskWithSuspiciousExtension()
{
byte[] buffer = new byte[100];
buffer[0] = 0x4D;
buffer[1] = 0x5A;
using (var stream = new MemoryStream(buffer))
{
var report = FileAnalyzer.Analyze(stream, "danger.exe");
Assert.False(report.IsSafe);
Assert.True(report.IsSuspicious);
Assert.Equal(70, report.RiskScore);
Assert.Equal(FileRiskLevel.Medium, report.RiskLevel);
Assert.Contains(report.Issues, i => i.Type == IssueType.SuspiciousExtension);
}
}
[Fact]
public void Analyze_MimeMismatch_ShouldBeDetected()
{
byte[] buffer = new byte[100];
buffer[0] = 0x25; // %
buffer[1] = 0x50; // P
buffer[2] = 0x44; // D
buffer[3] = 0x46; // F
using (var stream = new MemoryStream(buffer))
{
var report = FileAnalyzer.Analyze(stream, "report.pdf", "image/jpeg");
Assert.True(report.IsSuspicious);
Assert.Contains(report.Issues, i => i.Type == IssueType.MimeMismatch);
}
}
[Fact]
public void Analyze_DocxStructureInZip_ShouldRefineToDocx()
{
using (var ms = new MemoryStream())
{
using (var archive = new ZipArchive(ms, ZipArchiveMode.Create, true))
{
var entry = archive.CreateEntry("word/document.xml");
using (var writer = new StreamWriter(entry.Open()))
{
writer.Write("<xml>document content</xml>");
}
}
ms.Position = 0;
var report = FileAnalyzer.Analyze(ms, "test.zip");
Assert.Equal("docx", report.ActualFileType);
Assert.Equal("application/vnd.openxmlformats-officedocument.wordprocessingml.document", report.DetectedMimeType);
}
}
[Fact]
public void Analyze_XlsxStructureInZip_ShouldRefineToXlsx()
{
using (var ms = new MemoryStream())
{
using (var archive = new ZipArchive(ms, ZipArchiveMode.Create, true))
{
var entry = archive.CreateEntry("xl/workbook.xml");
using (var writer = new StreamWriter(entry.Open()))
{
writer.Write("<xml>workbook content</xml>");
}
}
ms.Position = 0;
var report = FileAnalyzer.Analyze(ms, "report.xlsx");
Assert.Equal("xlsx", report.ActualFileType);
Assert.Equal("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", report.DetectedMimeType);
Assert.True(report.IsSafe);
}
}
[Fact]
public void Analyze_ZipContainingExecutable_ShouldFlagExecutableContent()
{
using (var ms = new MemoryStream())
{
using (var archive = new ZipArchive(ms, ZipArchiveMode.Create, true))
{
var entry = archive.CreateEntry("malware.exe");
using (var writer = new StreamWriter(entry.Open()))
{
writer.Write("some fake executable code");
}
}
ms.Position = 0;
var report = FileAnalyzer.Analyze(ms, "files.zip");
Assert.False(report.IsSafe);
Assert.True(report.IsSuspicious);
Assert.Equal(85, report.RiskScore);
Assert.Equal(FileRiskLevel.High, report.RiskLevel);
Assert.Contains(report.Issues, i => i.Type == IssueType.ExecutableContentDetected);
}
}
[Fact]
public void Analyze_PolyglotPdfExe_ShouldFlagMultipleSignature()
{
byte[] buffer = new byte[1024];
buffer[0] = 0x25;
buffer[1] = 0x50;
buffer[2] = 0x44;
buffer[3] = 0x46;
int mzOffset = 100;
buffer[mzOffset] = 0x4D;
buffer[mzOffset + 1] = 0x5A;
int peOffset = 16;
buffer[mzOffset + 0x3C] = (byte)peOffset;
buffer[mzOffset + 0x3D] = 0;
buffer[mzOffset + 0x3E] = 0;
buffer[mzOffset + 0x3F] = 0;
int peStart = mzOffset + peOffset;
buffer[peStart] = 0x50;
buffer[peStart + 1] = 0x45;
buffer[peStart + 2] = 0x00;
buffer[peStart + 3] = 0x00;
using (var stream = new MemoryStream(buffer))
{
var report = FileAnalyzer.Analyze(stream, "document.pdf");
Assert.False(report.IsSafe);
Assert.True(report.IsSuspicious);
Assert.Equal(95, report.RiskScore);
Assert.Contains(report.Issues, i => i.Type == IssueType.MultipleSignatureDetected);
}
}
[Fact]
public void EntropyCalculator_PlainTextVsRandomBytes()
{
byte[] textBytes = System.Text.Encoding.ASCII.GetBytes(new string('A', 1000));
double textEntropy = EntropyCalculator.Calculate(textBytes, textBytes.Length);
byte[] randomBytes = new byte[1000];
new Random().NextBytes(randomBytes);
double randomEntropy = EntropyCalculator.Calculate(randomBytes, randomBytes.Length);
Assert.True(textEntropy < 1.0);
Assert.True(randomEntropy > 7.0);
}
[Fact]
public void Analyze_HighEntropyTextFile_ShouldFlagSuspicious()
{
byte[] randomBytes = new byte[2000];
new Random().NextBytes(randomBytes);
using (var stream = new MemoryStream(randomBytes))
{
var report = FileAnalyzer.Create()
.CheckEntropy(true, threshold: 7.2)
.Analyze(stream, "clean_text.txt");
Assert.False(report.IsSafe);
Assert.Contains(report.Issues, i => i.Type == IssueType.UnknownFileType && i.Description.Contains("high-entropy"));
}
}
[Fact]
public void FluentAPI_Configuration_ShouldRespectOptions()
{
byte[] buffer = new byte[100];
buffer[0] = 0x50;
buffer[1] = 0x4B;
buffer[2] = 0x03;
buffer[3] = 0x04;
using (var stream = new MemoryStream(buffer))
{
var report = FileAnalyzer.Create()
.ValidateSignature(false)
.ValidateStructure(false)
.CalculateRiskScore(false)
.Analyze(stream, "invoice.pdf");
Assert.True(report.IsSafe);
Assert.Empty(report.Issues);
Assert.Equal(0, report.RiskScore);
}
}
}
}