From 9611de0dde4c3d2ed935d8a57994c65254937056 Mon Sep 17 00:00:00 2001
From: Andreas Mueller <webmaster@am-wd.de>
Date: Sat, 18 Mar 2023 13:47:19 +0100
Subject: [PATCH] Implemented Ar Reader/Writer and UnitTests

---
 AMWD.Common/Packing/Ar/ArFileInfo.cs         |   2 -
 AMWD.Common/Packing/Ar/ArReader.cs           |   2 +-
 UnitTests/Common/Packing/Ar/ArReaderTests.cs | 124 +++++++++++++++++++
 3 files changed, 125 insertions(+), 3 deletions(-)

diff --git a/AMWD.Common/Packing/Ar/ArFileInfo.cs b/AMWD.Common/Packing/Ar/ArFileInfo.cs
index fdd05be..f0cbc38 100644
--- a/AMWD.Common/Packing/Ar/ArFileInfo.cs
+++ b/AMWD.Common/Packing/Ar/ArFileInfo.cs
@@ -1,7 +1,5 @@
 using System;
 
-//[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("UnitTests")]
-
 namespace AMWD.Common.Packing.Ar
 {
 	/// <summary>
diff --git a/AMWD.Common/Packing/Ar/ArReader.cs b/AMWD.Common/Packing/Ar/ArReader.cs
index e59f1e3..a260bb6 100644
--- a/AMWD.Common/Packing/Ar/ArReader.cs
+++ b/AMWD.Common/Packing/Ar/ArReader.cs
@@ -161,7 +161,7 @@ namespace AMWD.Common.Packing.Ar
 			byte[] magic = new byte[2];
 			inStream.Read(magic, 0, magic.Length);
 
-			if (magic[0] != 0x60 || magic[1] != 0x0A)
+			if (magic[0] != 0x60 || magic[1] != 0x0A) // `\n
 				throw new FormatException("Invalid file magic");
 
 			return new ArFileInfoExtended
diff --git a/UnitTests/Common/Packing/Ar/ArReaderTests.cs b/UnitTests/Common/Packing/Ar/ArReaderTests.cs
index 5b0bc48..688f54e 100644
--- a/UnitTests/Common/Packing/Ar/ArReaderTests.cs
+++ b/UnitTests/Common/Packing/Ar/ArReaderTests.cs
@@ -217,6 +217,126 @@ namespace UnitTests.Common.Packing.Ar
 			}
 		}
 
+		[TestMethod]
+		[ExpectedException(typeof(ArgumentException))]
+		public void ShouldThrowExceptionOnMissingRead()
+		{
+			// Arrange
+			using var stream = new OverrideStream();
+			stream.CanReadOR = false;
+			stream.CanSeekOR = true;
+			stream.CanWriteOR = true;
+
+			// Act
+			var reader = new ArReader(stream);
+
+			// Assert - ArgumentException
+			Assert.Fail();
+		}
+
+		[TestMethod]
+		[ExpectedException(typeof(ArgumentException))]
+		public void ShouldThrowExceptionOnMissingSeek()
+		{
+			// Arrange
+			using var stream = new OverrideStream();
+			stream.CanReadOR = true;
+			stream.CanSeekOR = false;
+			stream.CanWriteOR = true;
+
+			// Act
+			var reader = new ArReader(stream);
+
+			// Assert - ArgumentException
+			Assert.Fail();
+		}
+
+		[TestMethod]
+		[ExpectedException(typeof(ArgumentException))]
+		public void ShouldThrowExceptionOnMissingWrite()
+		{
+			// Arrange
+			using var stream = new OverrideStream();
+			stream.CanReadOR = true;
+			stream.CanSeekOR = true;
+			stream.CanWriteOR = false;
+
+			var reader = new ArReader(inStream);
+
+			// Act
+			reader.ReadFile("abcd.tmp", stream);
+
+			// Assert - ArgumentException
+			Assert.Fail();
+		}
+
+		[TestMethod]
+		[ExpectedException(typeof(FormatException))]
+		public void ShouldThrowExceptionOnInvalidArchive()
+		{
+			// Arrange
+			inStream.Seek(8, SeekOrigin.Begin);
+
+			// Act
+			_ = new ArReader(inStream);
+
+			// Assert - FormatException
+			Assert.Fail();
+		}
+
+		[TestMethod]
+		[ExpectedException(typeof(FormatException))]
+		public void ShouldThrowExceptionOnInvalidMagic()
+		{
+			// Arrange
+			inStream.Seek(0, SeekOrigin.End);
+			inStream.Write(Encoding.ASCII.GetBytes($"{"foo.bar",-16}{"123456789",-12}123   456   100644  {"0",-10}´\n"));
+			inStream.Seek(0, SeekOrigin.Begin);
+
+			// Act
+			_ = new ArReader(inStream);
+
+			// Assert - FormatException
+			Assert.Fail();
+		}
+
+		[TestMethod]
+		public void ShouldWriteNothingToStreamForMissingFile()
+		{
+			// Arrange
+			var reader = new ArReader(inStream);
+
+			// Act
+			using var ms = new MemoryStream();
+
+			reader.ReadFile("foo.bar", ms);
+			ms.Seek(0, SeekOrigin.Begin);
+
+			// Assert
+			Assert.AreEqual(0, ms.Length);
+		}
+
+		[TestMethod]
+		public void ShouldWriteNothingToDiskForMissingFile()
+		{
+			// Arrange
+			string tmpFile = Path.GetTempFileName();
+			var reader = new ArReader(inStream);
+
+			try
+			{
+				// Act
+				reader.ReadFile("foo.bar", tmpFile);
+
+				// Assert
+				Assert.AreEqual(0, new FileInfo(tmpFile).Length);
+			}
+			finally
+			{
+				File.Delete(tmpFile);
+			}
+		}
+
 		private class OverrideStream : MemoryStream
 		{
 			public override bool CanWrite => CanWriteOR;
@@ -226,6 +346,10 @@ namespace UnitTests.Common.Packing.Ar
 			public override bool CanSeek => CanSeekOR;
 
 			public bool CanSeekOR { get; set; }
+
+			public override bool CanRead => CanReadOR;
+
+			public bool CanReadOR { get; set; }
 		}
 	}
 }