Fix HierarchicalRomFileTable not working and add tests

src/LibHac/IO/RomFs/HierarchicalRomFileTable.cs

@@ -207,6 +207,8 @@ namespace LibHac.IO.RomFs
             path = PathTools.Normalize(path);
             ReadOnlySpan<byte> pathBytes = GetUtf8Bytes(path);
 
+            if(path == "/") throw new ArgumentException("Path cannot be empty");
+
             CreateFileRecursiveInternal(pathBytes, ref fileInfo);
         }
 
@@ -347,7 +349,7 @@ namespace LibHac.IO.RomFs
             {
                 ref FileRomEntry entry = ref FileTable.AddOrGet(ref key, out int offset, out bool alreadyExists, out _);
                 entry.Info = fileInfo;
-                if (alreadyExists) entry.NextSibling = -1;
+                if (!alreadyExists) entry.NextSibling = -1;
 
                 ref DirectoryRomEntry parent = ref DirectoryTable.GetValueReference(prevOffset);
 

tests/LibHac.Tests/RomFsTests.cs

@@ -0,0 +1,204 @@
+using System;
+using LibHac.IO.RomFs;
+using Xunit;
+
+namespace LibHac.Tests
+{
+    public class RomFsTests
+    {
+        [Fact]
+        public void SimpleAddAndRead()
+        {
+            const string path = "/a/b";
+
+            var table = new HierarchicalRomFileTable();
+            var item = new RomFileInfo { Length = 1, Offset = 1 };
+
+            table.AddFile(path, ref item);
+            bool success = table.TryOpenFile(path, out RomFileInfo readItem);
+
+            Assert.True(success, "Table read failed");
+            Assert.Equal(item, readItem);
+        }
+
+        [Fact]
+        public void UpdateExistingFile()
+        {
+            const string path = "/a/b";
+
+            var table = new HierarchicalRomFileTable();
+            var originalItem = new RomFileInfo { Length = 1, Offset = 1 };
+            var newItem = new RomFileInfo { Length = 1, Offset = 1 };
+
+            table.AddFile(path, ref originalItem);
+            table.AddFile(path, ref newItem);
+
+            bool success = table.TryOpenFile(path, out RomFileInfo readItem);
+
+            Assert.True(success, "Table read failed");
+            Assert.Equal(newItem, readItem);
+        }
+
+        [Fact]
+        public void AddingDirectory()
+        {
+            var table = new HierarchicalRomFileTable();
+            var expectedPosition = new FindPosition { NextDirectory = -1, NextFile = -1 };
+
+            table.AddDirectory("/dir");
+            bool success = table.TryOpenDirectory("/dir", out FindPosition position);
+
+            Assert.True(success, "Opening directory failed");
+            Assert.Equal(expectedPosition, position);
+        }
+
+        [Fact]
+        public void AddingEmptyPathThrows()
+        {
+            var table = new HierarchicalRomFileTable();
+            var item = new RomFileInfo();
+
+            Assert.Throws<ArgumentException>(() => table.AddFile("", ref item));
+        }
+
+        [Fact]
+        public void OpeningNonexistentFileFails()
+        {
+            var table = new HierarchicalRomFileTable();
+
+            bool success = table.TryOpenFile("/foo", out _);
+            Assert.False(success);
+        }
+
+        [Fact]
+        public void OpeningNonexistentDirectoryFails()
+        {
+            var table = new HierarchicalRomFileTable();
+
+            bool success = table.TryOpenDirectory("/foo", out _);
+            Assert.False(success);
+        }
+
+        [Fact]
+        public void OpeningFileAsDirectoryFails()
+        {
+            var table = new HierarchicalRomFileTable();
+            var fileInfo = new RomFileInfo();
+            table.AddFile("/file", ref fileInfo);
+
+            bool success = table.TryOpenDirectory("/file", out _);
+            Assert.False(success);
+        }
+
+        [Fact]
+        public void OpeningDirectoryAsFileFails()
+        {
+            var table = new HierarchicalRomFileTable();
+            table.AddDirectory("/dir");
+
+            bool success = table.TryOpenFile("/dir", out _);
+            Assert.False(success);
+        }
+
+        [Fact]
+        public void ChildFileIteration()
+        {
+            const int fileCount = 10;
+            var table = new HierarchicalRomFileTable();
+
+            for (int i = 0; i < fileCount; i++)
+            {
+                var item = new RomFileInfo { Length = i, Offset = i };
+                table.AddFile($"/a/{i}", ref item);
+            }
+
+            bool openDirSuccess = table.TryOpenDirectory("/a", out FindPosition position);
+            Assert.True(openDirSuccess, "Error opening directory");
+
+            for (int i = 0; i < fileCount; i++)
+            {
+                var expectedItem = new RomFileInfo { Length = i, Offset = i };
+                string expectedName = i.ToString();
+
+                bool success = table.FindNextFile(ref position, out RomFileInfo actualItem, out string actualName);
+
+                Assert.True(success, $"Failed reading file {i}");
+                Assert.Equal(expectedItem, actualItem);
+                Assert.Equal(expectedName, actualName);
+            }
+
+            bool endOfFilesSuccess = table.FindNextFile(ref position, out _, out _);
+            Assert.False(endOfFilesSuccess, "Table returned more files than it should");
+        }
+
+        [Fact]
+        public void ChildFileIterationPeek()
+        {
+            var table = new HierarchicalRomFileTable();
+
+            var itemA = new RomFileInfo { Length = 1, Offset = 1 };
+            var itemB = new RomFileInfo { Length = 2, Offset = 2 };
+
+            table.AddFile("/a/a", ref itemA);
+            table.AddFile("/a/b", ref itemB);
+
+            table.TryOpenDirectory("/a", out FindPosition position);
+
+            table.TryOpenFile(position.NextFile, out RomFileInfo peekItemA);
+            Assert.Equal(itemA, peekItemA);
+
+            table.FindNextFile(ref position, out RomFileInfo iterateItemA, out _);
+            Assert.Equal(itemA, iterateItemA);
+
+            table.TryOpenFile(position.NextFile, out RomFileInfo peekItemB);
+            Assert.Equal(itemB, peekItemB);
+
+            table.FindNextFile(ref position, out RomFileInfo iterateItemB, out _);
+            Assert.Equal(itemB, iterateItemB);
+        }
+
+        [Fact]
+        public void AddingCousinFiles()
+        {
+            var table = new HierarchicalRomFileTable();
+
+            var itemB1 = new RomFileInfo { Length = 1, Offset = 1 };
+            var itemB2 = new RomFileInfo { Length = 2, Offset = 2 };
+            var itemB3 = new RomFileInfo { Length = 3, Offset = 3 };
+
+            table.AddFile("/a/b1/c", ref itemB1);
+            table.AddFile("/a/b2/c", ref itemB2);
+            table.AddFile("/a/b3/c", ref itemB3);
+
+            table.TryOpenFile("/a/b1/c", out RomFileInfo actualItemB1);
+            table.TryOpenFile("/a/b2/c", out RomFileInfo actualItemB2);
+            table.TryOpenFile("/a/b3/c", out RomFileInfo actualItemB3);
+
+            Assert.Equal(itemB1, actualItemB1);
+            Assert.Equal(itemB2, actualItemB2);
+            Assert.Equal(itemB3, actualItemB3);
+        }
+
+        [Fact]
+        public void AddingSiblingFiles()
+        {
+            var table = new HierarchicalRomFileTable();
+
+            var itemC1 = new RomFileInfo { Length = 1, Offset = 1 };
+            var itemC2 = new RomFileInfo { Length = 2, Offset = 2 };
+            var itemC3 = new RomFileInfo { Length = 3, Offset = 3 };
+
+            table.AddFile("/a/b/c1", ref itemC1);
+            table.AddFile("/a/b/c2", ref itemC2);
+            table.AddFile("/a/b/c3", ref itemC3);
+
+            table.TryOpenFile("/a/b/c1", out RomFileInfo actualItemC1);
+            table.TryOpenFile("/a/b/c2", out RomFileInfo actualItemC2);
+            table.TryOpenFile("/a/b/c3", out RomFileInfo actualItemC3);
+
+            Assert.Equal(itemC1, actualItemC1);
+            Assert.Equal(itemC2, actualItemC2);
+            Assert.Equal(itemC3, actualItemC3);
+        }
+    }
+}