Address PR #282 review feedback

- Fix argument validation: CreateAvdAsync/DeleteAvdAsync now throw
  ArgumentException for empty strings, ArgumentNullException for null,
  and validate before RequireAvdManagerPath()
- Make AndroidEnvironmentHelper internal, remove unused GetToolEnvironment
- Add ANDROID_USER_HOME to ConfigureEnvironment for consistent AVD
  location across tools (matches SdkManager behavior)
- Add AndroidUserHome constant to EnvironmentVariableNames
- Fix hard-coded AVD directory: use GetAvdRootDirectory() that respects
  ANDROID_AVD_HOME and ANDROID_USER_HOME env vars
- Re-list after CreateAvdAsync to get actual path from avdmanager
- Add 5 new validation tests for Create/DeleteAvdAsync

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: rmarinho

src/Xamarin.Android.Tools.AndroidSdk/EnvironmentVariableNames.cs

@@ -40,5 +40,11 @@ internal static class EnvironmentVariableNames
 		/// Executable file extensions (Windows).
 		/// </summary>
 		public const string PathExt = "PATHEXT";
+
+		/// <summary>
+		/// Overrides the default location for Android user-specific data
+		/// (AVDs, preferences, etc.). Defaults to $HOME/.android.
+		/// </summary>
+		public const string AndroidUserHome = "ANDROID_USER_HOME";
 	}
 }

src/Xamarin.Android.Tools.AndroidSdk/Runners/AndroidEnvironmentHelper.cs

@@ -11,35 +11,12 @@ namespace Xamarin.Android.Tools;
 /// <summary>
 /// Helper for setting up environment variables for Android SDK tools.
 /// </summary>
-public static class AndroidEnvironmentHelper
+internal static class AndroidEnvironmentHelper
 {
-	/// <summary>
-	/// Creates environment variables for running Android SDK tools.
-	/// </summary>
-	public static Dictionary<string, string>? GetToolEnvironment (string? sdkPath, string? jdkPath)
-	{
-		if (string.IsNullOrEmpty (sdkPath) && string.IsNullOrEmpty (jdkPath))
-			return null;
-
-		var env = new Dictionary<string, string> (StringComparer.OrdinalIgnoreCase);
-
-		if (!string.IsNullOrEmpty (sdkPath))
-			env [EnvironmentVariableNames.AndroidHome] = sdkPath;
-
-		if (!string.IsNullOrEmpty (jdkPath)) {
-			env [EnvironmentVariableNames.JavaHome] = jdkPath;
-			var jdkBin = Path.Combine (jdkPath, "bin");
-			var currentPath = Environment.GetEnvironmentVariable (EnvironmentVariableNames.Path) ?? "";
-			env [EnvironmentVariableNames.Path] = string.IsNullOrEmpty (currentPath) ? jdkBin : jdkBin + Path.PathSeparator + currentPath;
-		}
-
-		return env;
-	}
-
 	/// <summary>
 	/// Configures environment variables on a ProcessStartInfo for running Android SDK tools.
 	/// </summary>
-	public static void ConfigureEnvironment (ProcessStartInfo psi, string? sdkPath, string? jdkPath)
+	internal static void ConfigureEnvironment (ProcessStartInfo psi, string? sdkPath, string? jdkPath)
 	{
 		if (!string.IsNullOrEmpty (sdkPath))
 			psi.EnvironmentVariables [EnvironmentVariableNames.AndroidHome] = sdkPath;
@@ -50,5 +27,11 @@ public static void ConfigureEnvironment (ProcessStartInfo psi, string? sdkPath,
 			var currentPath = psi.EnvironmentVariables [EnvironmentVariableNames.Path] ?? "";
 			psi.EnvironmentVariables [EnvironmentVariableNames.Path] = string.IsNullOrEmpty (currentPath) ? jdkBin : jdkBin + Path.PathSeparator + currentPath;
 		}
+
+		// Set ANDROID_USER_HOME for consistent AVD location across tools (matches SdkManager behavior)
+		if (!psi.EnvironmentVariables.ContainsKey (EnvironmentVariableNames.AndroidUserHome)) {
+			psi.EnvironmentVariables [EnvironmentVariableNames.AndroidUserHome] = Path.Combine (
+				Environment.GetFolderPath (Environment.SpecialFolder.UserProfile), ".android");
+		}
 	}
 }

src/Xamarin.Android.Tools.AndroidSdk/Runners/AvdManagerRunner.cs

@@ -91,11 +91,16 @@ public async Task<IReadOnlyList<AvdInfo>> ListAvdsAsync (CancellationToken cance
 	public async Task<AvdInfo> CreateAvdAsync (string name, string systemImage, string? deviceProfile = null,
 		bool force = false, CancellationToken cancellationToken = default)
 	{
-		var avdManagerPath = RequireAvdManagerPath ();
-		if (string.IsNullOrEmpty (name))
+		if (name is null)
 			throw new ArgumentNullException (nameof (name));
-		if (string.IsNullOrEmpty (systemImage))
+		if (name.Length == 0)
+			throw new ArgumentException ("Value cannot be an empty string.", nameof (name));
+		if (systemImage is null)
 			throw new ArgumentNullException (nameof (systemImage));
+		if (systemImage.Length == 0)
+			throw new ArgumentException ("Value cannot be an empty string.", nameof (systemImage));
+
+		var avdManagerPath = RequireAvdManagerPath ();
 
 		// Check if AVD already exists — return it instead of failing
 		if (!force) {
@@ -106,9 +111,7 @@ public async Task<AvdInfo> CreateAvdAsync (string name, string systemImage, stri
 		}
 
 		// Detect orphaned AVD directory (folder exists without .ini registration).
-		var avdDir = Path.Combine (
-			Environment.GetFolderPath (Environment.SpecialFolder.UserProfile),
-			".android", "avd", $"{name}.avd");
+		var avdDir = Path.Combine (GetAvdRootDirectory (), $"{name}.avd");
 		if (Directory.Exists (avdDir))
 			force = true;
 
@@ -142,15 +145,27 @@ public async Task<AvdInfo> CreateAvdAsync (string name, string systemImage, stri
 			throw new InvalidOperationException ($"Failed to create AVD '{name}': {errorOutput}");
 		}
 
+		// Re-list to get the actual path from avdmanager (respects ANDROID_USER_HOME/ANDROID_AVD_HOME)
+		var avds = await ListAvdsAsync (cancellationToken).ConfigureAwait (false);
+		var created = avds.FirstOrDefault (a => string.Equals (a.Name, name, StringComparison.OrdinalIgnoreCase));
+		if (created is not null)
+			return created;
+
+		// Fallback if re-list didn't find it
 		return new AvdInfo {
 			Name = name,
 			DeviceProfile = deviceProfile,
-			Path = avdDir,
+			Path = Path.Combine (GetAvdRootDirectory (), $"{name}.avd"),
 		};
 	}
 
 	public async Task DeleteAvdAsync (string name, CancellationToken cancellationToken = default)
 	{
+		if (name is null)
+			throw new ArgumentNullException (nameof (name));
+		if (name.Length == 0)
+			throw new ArgumentException ("Value cannot be an empty string.", nameof (name));
+
 		var avdManagerPath = RequireAvdManagerPath ();
 
 		using var stderr = new StringWriter ();
@@ -186,5 +201,26 @@ internal static List<AvdInfo> ParseAvdListOutput (string output)
 
 		return avds;
 	}
+
+	/// <summary>
+	/// Resolves the AVD root directory, respecting ANDROID_AVD_HOME and ANDROID_USER_HOME.
+	/// </summary>
+	static string GetAvdRootDirectory ()
+	{
+		// ANDROID_AVD_HOME takes highest priority
+		var avdHome = Environment.GetEnvironmentVariable ("ANDROID_AVD_HOME");
+		if (!string.IsNullOrEmpty (avdHome))
+			return avdHome;
+
+		// ANDROID_USER_HOME/avd is the next option
+		var userHome = Environment.GetEnvironmentVariable (EnvironmentVariableNames.AndroidUserHome);
+		if (!string.IsNullOrEmpty (userHome))
+			return Path.Combine (userHome, "avd");
+
+		// Default: ~/.android/avd
+		return Path.Combine (
+			Environment.GetFolderPath (Environment.SpecialFolder.UserProfile),
+			".android", "avd");
+	}
 }
 

tests/Xamarin.Android.Tools.AndroidSdk-Tests/AvdManagerRunnerTests.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
 using System.IO;
 using NUnit.Framework;
 
@@ -160,4 +161,39 @@ public void AvdManagerPath_MissingSdk_ReturnsNull ()
 		var runner = new AvdManagerRunner (() => "/nonexistent/path", null);
 		Assert.IsNull (runner.AvdManagerPath);
 	}
+
+	[Test]
+	public void CreateAvdAsync_NullName_ThrowsArgumentNullException ()
+	{
+		var runner = new AvdManagerRunner (() => "/fake/sdk", null);
+		Assert.ThrowsAsync<ArgumentNullException> (() => runner.CreateAvdAsync (null!, "system-image"));
+	}
+
+	[Test]
+	public void CreateAvdAsync_EmptyName_ThrowsArgumentException ()
+	{
+		var runner = new AvdManagerRunner (() => "/fake/sdk", null);
+		Assert.ThrowsAsync<ArgumentException> (() => runner.CreateAvdAsync ("", "system-image"));
+	}
+
+	[Test]
+	public void CreateAvdAsync_EmptySystemImage_ThrowsArgumentException ()
+	{
+		var runner = new AvdManagerRunner (() => "/fake/sdk", null);
+		Assert.ThrowsAsync<ArgumentException> (() => runner.CreateAvdAsync ("test-avd", ""));
+	}
+
+	[Test]
+	public void DeleteAvdAsync_NullName_ThrowsArgumentNullException ()
+	{
+		var runner = new AvdManagerRunner (() => "/fake/sdk", null);
+		Assert.ThrowsAsync<ArgumentNullException> (() => runner.DeleteAvdAsync (null!));
+	}
+
+	[Test]
+	public void DeleteAvdAsync_EmptyName_ThrowsArgumentException ()
+	{
+		var runner = new AvdManagerRunner (() => "/fake/sdk", null);
+		Assert.ThrowsAsync<ArgumentException> (() => runner.DeleteAvdAsync (""));
+	}
 }