Use shared ConfigureEnvironment, ProcessUtils.CreateProcessStartInfo, add tests

- Replace manual ProcessStartInfo with ProcessUtils.CreateProcessStartInfo
- Use AndroidEnvironmentHelper.ConfigureEnvironment instead of duplicated method
- Extract ParseListAvdsOutput as internal static for testability
- Return IReadOnlyList<string> from ListAvdNamesAsync
- Add RequireEmulatorPath helper
- Add EmulatorRunnerTests (7 tests): parsing, path discovery, null/missing sdk

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

Author: rmarinho

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

@@ -44,34 +44,27 @@ public string? EmulatorPath {
 
 	public bool IsAvailable => EmulatorPath is not null;
 
-	void ConfigureEnvironment (ProcessStartInfo psi)
+	string RequireEmulatorPath ()
 	{
-		var sdkPath = getSdkPath ();
-		if (!string.IsNullOrEmpty (sdkPath))
-			psi.EnvironmentVariables ["ANDROID_HOME"] = sdkPath;
+		return EmulatorPath ?? throw new InvalidOperationException ("Android Emulator not found.");
+	}
 
-		var jdkPath = getJdkPath?.Invoke ();
-		if (!string.IsNullOrEmpty (jdkPath))
-			psi.EnvironmentVariables ["JAVA_HOME"] = jdkPath;
+	void ConfigureEnvironment (ProcessStartInfo psi)
+	{
+		AndroidEnvironmentHelper.ConfigureEnvironment (psi, getSdkPath (), getJdkPath?.Invoke ());
 	}
 
 	public Process StartAvd (string avdName, bool coldBoot = false, string? additionalArgs = null)
 	{
-		if (!IsAvailable)
-			throw new InvalidOperationException ("Android Emulator not found.");
+		var emulatorPath = RequireEmulatorPath ();
 
-		var args = $"-avd \"{avdName}\"";
+		var args = new List<string> { "-avd", avdName };
 		if (coldBoot)
-			args += " -no-snapshot-load";
+			args.Add ("-no-snapshot-load");
 		if (!string.IsNullOrEmpty (additionalArgs))
-			args += " " + additionalArgs;
-
-		var psi = new ProcessStartInfo {
-			FileName = EmulatorPath!,
-			Arguments = args,
-			UseShellExecute = false,
-			CreateNoWindow = true
-		};
+			args.Add (additionalArgs);
+
+		var psi = ProcessUtils.CreateProcessStartInfo (emulatorPath, args.ToArray ());
 		ConfigureEnvironment (psi);
 
 		var process = new Process { StartInfo = psi };
@@ -80,29 +73,27 @@ public Process StartAvd (string avdName, bool coldBoot = false, string? addition
 		return process;
 	}
 
-	public async Task<List<string>> ListAvdNamesAsync (CancellationToken cancellationToken = default)
+	public async Task<IReadOnlyList<string>> ListAvdNamesAsync (CancellationToken cancellationToken = default)
 	{
-		if (!IsAvailable)
-			throw new InvalidOperationException ("Android Emulator not found.");
+		var emulatorPath = RequireEmulatorPath ();
 
 		using var stdout = new StringWriter ();
-		var psi = new ProcessStartInfo {
-			FileName = EmulatorPath!,
-			Arguments = "-list-avds",
-			UseShellExecute = false,
-			CreateNoWindow = true
-		};
+		var psi = ProcessUtils.CreateProcessStartInfo (emulatorPath, "-list-avds");
 		ConfigureEnvironment (psi);
 
 		await ProcessUtils.StartProcess (psi, stdout, null, cancellationToken).ConfigureAwait (false);
 
+		return ParseListAvdsOutput (stdout.ToString ());
+	}
+
+	internal static List<string> ParseListAvdsOutput (string output)
+	{
 		var avds = new List<string> ();
-		foreach (var line in stdout.ToString ().Split ('\n')) {
+		foreach (var line in output.Split ('\n')) {
 			var trimmed = line.Trim ();
 			if (!string.IsNullOrEmpty (trimmed))
 				avds.Add (trimmed);
 		}
-
 		return avds;
 	}
 }

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

@@ -0,0 +1,89 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.IO;
+using NUnit.Framework;
+
+namespace Xamarin.Android.Tools.Tests;
+
+[TestFixture]
+public class EmulatorRunnerTests
+{
+	[Test]
+	public void ParseListAvdsOutput_MultipleAvds ()
+	{
+		var output = "Pixel_7_API_35\nMAUI_Emulator\nNexus_5X\n";
+
+		var avds = EmulatorRunner.ParseListAvdsOutput (output);
+
+		Assert.AreEqual (3, avds.Count);
+		Assert.AreEqual ("Pixel_7_API_35", avds [0]);
+		Assert.AreEqual ("MAUI_Emulator", avds [1]);
+		Assert.AreEqual ("Nexus_5X", avds [2]);
+	}
+
+	[Test]
+	public void ParseListAvdsOutput_EmptyOutput ()
+	{
+		var avds = EmulatorRunner.ParseListAvdsOutput ("");
+		Assert.AreEqual (0, avds.Count);
+	}
+
+	[Test]
+	public void ParseListAvdsOutput_WindowsNewlines ()
+	{
+		var output = "Pixel_7_API_35\r\nMAUI_Emulator\r\n";
+
+		var avds = EmulatorRunner.ParseListAvdsOutput (output);
+
+		Assert.AreEqual (2, avds.Count);
+		Assert.AreEqual ("Pixel_7_API_35", avds [0]);
+		Assert.AreEqual ("MAUI_Emulator", avds [1]);
+	}
+
+	[Test]
+	public void ParseListAvdsOutput_BlankLines ()
+	{
+		var output = "\nPixel_7_API_35\n\n\nMAUI_Emulator\n\n";
+
+		var avds = EmulatorRunner.ParseListAvdsOutput (output);
+
+		Assert.AreEqual (2, avds.Count);
+	}
+
+	[Test]
+	public void EmulatorPath_FindsInSdk ()
+	{
+		var tempDir = Path.Combine (Path.GetTempPath (), $"emu-test-{Path.GetRandomFileName ()}");
+		var emulatorDir = Path.Combine (tempDir, "emulator");
+		Directory.CreateDirectory (emulatorDir);
+
+		try {
+			var emuName = OS.IsWindows ? "emulator.exe" : "emulator";
+			File.WriteAllText (Path.Combine (emulatorDir, emuName), "");
+
+			var runner = new EmulatorRunner (() => tempDir);
+
+			Assert.IsNotNull (runner.EmulatorPath);
+			Assert.IsTrue (runner.IsAvailable);
+		} finally {
+			Directory.Delete (tempDir, true);
+		}
+	}
+
+	[Test]
+	public void EmulatorPath_MissingSdk_ReturnsNull ()
+	{
+		var runner = new EmulatorRunner (() => "/nonexistent/path");
+		Assert.IsNull (runner.EmulatorPath);
+		Assert.IsFalse (runner.IsAvailable);
+	}
+
+	[Test]
+	public void EmulatorPath_NullSdk_ReturnsNull ()
+	{
+		var runner = new EmulatorRunner (() => null);
+		Assert.IsNull (runner.EmulatorPath);
+		Assert.IsFalse (runner.IsAvailable);
+	}
+}