Better argument validation in DirectoryBuilder, resolve #1

Author: martindevans

Wazzy.Tests/VfsTests.cs

@@ -0,0 +1,20 @@
+using Wasmtime;
+using Wazzy.Extensions;
+using Wazzy.WasiSnapshotPreview1.FileSystem.Implementations.VirtualFileSystem.Builder;
+
+namespace Wazzy.Tests;
+
+[TestClass]
+public class VfsTests
+{
+    [TestMethod]
+    public void MapDirectory()
+    {
+        Assert.ThrowsException<ArgumentException>(() =>
+        {
+            new VirtualFileSystemBuilder()
+                .WithVirtualRoot(builder => { builder.MapDirectory("", ".", true); })
+                .Build();
+        });
+    }
+}

Wazzy.sln.DotSettings.user

@@ -1,5 +1,5 @@
 <wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
-	<s:String x:Key="/Default/Environment/Highlighting/HighlightingSourceSnapshotLocation/@EntryValue">C:\Users\Martin\AppData\Local\Temp\JetBrains\ReSharperPlatformVs17\vAny_ac125f2d\CoverageData\_Wazzy.1727317920\Snapshot\snapshot.utdcvr</s:String>
+	
 	<s:String x:Key="/Default/Environment/UnitTesting/UnitTestSessionStore/Sessions/=72b34e5d_002D828f_002D4842_002Db55e_002D5786e03b2df9/@EntryIndexedValue">&lt;SessionState ContinuousTestingMode="0" Name="All tests from &amp;lt;Wazzy.Tests&amp;gt;" xmlns="urn:schemas-jetbrains-com:jetbrains-ut-session"&gt;&#xD;
   &lt;Project Location="C:\Users\Martin\Documents\dotnet\Wazzy\Wazzy.Tests" Presentation="&amp;lt;Wazzy.Tests&amp;gt;" /&gt;&#xD;
 &lt;/SessionState&gt;</s:String>

Wazzy/WasiSnapshotPreview1/FileSystem/Implementations/VirtualFileSystem/Builder/DirectoryBuilder.cs

@@ -73,6 +73,9 @@ private string ValidatePath(string path)
 
     public DirectoryBuilder CreateVirtualDirectory(string name, Action<DirectoryBuilder> content)
     {
+        if (string.IsNullOrEmpty(name))
+            throw new ArgumentException("Cannot create a virtual directory with an empty name");
+
         var path = _fullPath + '/' + ValidatePath(name);
 
         _contentConstructors.Add(
@@ -96,6 +99,9 @@ public DirectoryBuilder CreateInMemoryFile(
         MemoryStream? backing = null,
         bool isReadOnly = false)
     {
+        if (string.IsNullOrEmpty(name))
+            throw new ArgumentException("Cannot create an in memory file with an empty name");
+
         _contentConstructors.Add(
             (_fullPath + '/' + ValidatePath(name), context =>
             {
@@ -114,6 +120,8 @@ public DirectoryBuilder MapFile(
         string hostPath,
         bool isReadonly = false)
     {
+        if (string.IsNullOrEmpty(name))
+            throw new ArgumentException("Cannot map a file with an empty name");
         if (!File.Exists(hostPath))
             throw new ArgumentException($"file {hostPath} does not exist", nameof(hostPath));
 
@@ -129,6 +137,8 @@ public DirectoryBuilder MapDirectory(
         string hostPath,
         bool isReadOnly = false)
     {
+        if (string.IsNullOrEmpty(name))
+            throw new ArgumentException("Cannot map a directory with an empty name");
         if (!Directory.Exists(hostPath))
             throw new ArgumentException($"directory {hostPath} does not exist", nameof(hostPath));