[fix-finder] Add unit tests for `EnvironmentFilesParser` utility

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Problem

The EnvironmentFilesParser class in src/Xamarin.Android.Build.Tasks/Utilities/EnvironmentFilesParser.cs has no unit tests. It contains non-trivial parsing logic for Android environment configuration files — detecting log levels, GC params, mono debug settings, HTTP handlers, assembly preload, and broken exception transitions — that should be covered by tests to prevent regressions.

Location

• File: src/Xamarin.Android.Build.Tasks/Utilities/EnvironmentFilesParser.cs
• Test directory: src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Tasks/

Current Code

The class parses environment variable files line by line, setting boolean flags and collecting lines:

class EnvironmentFilesParser
{
	public bool BrokenExceptionTransitions       { get; set; }
	public bool HaveHttpMessageHandler           { get; private set; }
	public bool HaveLogLevel                     { get; private set; }
	public bool HaveMonoDebug                    { get; private set; }
	public bool HaveMonoGCParams                 { get; private set; }
	public bool HaveTlsProvider                  { get; private set; }
	public bool UsesAssemblyPreload              { get; set; }
	public List<string> EnvironmentVariableLines { get; } = new List<string> ();

	public bool AreBrokenExceptionTransitionsEnabled (ITaskItem[] environments) { ... }
	public void Parse (ITaskItem[]? environments, SequencePointsMode sequencePointsMode, TaskLoggingHelper log) { ... }
}

Suggested Fix

Create a new test file src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Tasks/EnvironmentFilesParserTests.cs with tests covering the following behaviors. The class is internal but accessible via [InternalsVisibleTo("Xamarin.Android.Build.Tests")] in Properties/AssemblyInfo.cs.

Tests should create temporary files with specific environment variable content and verify the parser sets the correct flags.

Test cases to cover:

1. MONO_LOG_LEVEL= detection — Verify HaveLogLevel is set to true when a line starts with MONO_LOG_LEVEL=
2. MONO_GC_PARAMS= detection — Verify HaveMonoGCParams is set to true
3. MONO_GC_PARAMS= with old bridge warning — Verify that when the line contains bridge-implementation=old, the parser logs coded warning XA2000
4. MONO_DEBUG= detection — Verify HaveMonoDebug is set to true
5. MONO_DEBUG= with sequence points — When sequencePointsMode != SequencePointsMode.None and the line does not contain gen-compact-seq-points, verify that gen-compact-seq-points is appended to the line in EnvironmentVariableLines
6. XA_HTTP_CLIENT_HANDLER_TYPE= detection — Verify HaveHttpMessageHandler is set to true
7. mono.enable_assembly_preload= handling — Verify UsesAssemblyPreload is set; note this line should NOT appear in EnvironmentVariableLines (it's filtered via continue)
8. XA_BROKEN_EXCEPTION_TRANSITIONS= handling — Verify BrokenExceptionTransitions is set; note this line should NOT appear in EnvironmentVariableLines (it's filtered via continue)
9. AreBrokenExceptionTransitionsEnabled — Verify it returns true when a file contains a XA_BROKEN_EXCEPTION_TRANSITIONS= line, and false otherwise
10. Empty/null environments — Verify Parse handles null environments parameter without throwing
11. Multiple files — Verify flags are accumulated across multiple environment files

Example structure:

using System.Collections.Generic;
using System.IO;
using Microsoft.Build.Framework;
using Microsoft.Build.Utilities;
using NUnit.Framework;
using Xamarin.Android.Tasks;

namespace Xamarin.Android.Build.Tests
{
	[TestFixture]
	[Parallelizable (ParallelScope.Self)]
	public class EnvironmentFilesParserTests : BaseTest
	{
		string? tempDirectory;

		[SetUp]
		public void Setup ()
		{
			tempDirectory = Path.Combine (Path.GetTempPath (), Path.GetRandomFileName ());
			Directory.CreateDirectory (tempDirectory);
		}

		[TearDown]
		public void TearDown ()
		{
			if (tempDirectory != null && Directory.Exists (tempDirectory))
				Directory.Delete (tempDirectory, recursive: true);
		}

		ITaskItem CreateEnvFile (string content)
		{
			var path = Path.Combine (tempDirectory!, Path.GetRandomFileName () + ".env");
			File.WriteAllText (path, content);
			return new TaskItem (path);
		}

		[Test]
		public void DetectsMonoLogLevel ()
		{
			var envFile = CreateEnvFile ("MONO_LOG_LEVEL=debug");
			var parser = new EnvironmentFilesParser ();
			var engine = new MockBuildEngine (TestContext.Out);
			var log = new TaskLoggingHelper (engine, "Test");

			parser.Parse (new [] { envFile }, SequencePointsMode.None, log);

			Assert.IsTrue (parser.HaveLogLevel);
		}

		[Test]
		public void MonoGCParams_OldBridgeWarning ()
		{
			var envFile = CreateEnvFile ("MONO_GC_PARAMS=bridge-implementation=old");
			var warnings = new List<BuildWarningEventArgs> ();
			var engine = new MockBuildEngine (TestContext.Out, warnings: warnings);
			var log = new TaskLoggingHelper (engine, "Test");
			var parser = new EnvironmentFilesParser ();

			parser.Parse (new [] { envFile }, SequencePointsMode.None, log);

			Assert.IsTrue (parser.HaveMonoGCParams);
			Assert.AreEqual (1, warnings.Count);
			Assert.AreEqual ("XA2000", warnings [0].Code);
		}

		// ... additional tests for each behavior listed above
	}
}

Guidelines

• Follow existing test patterns in src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Tasks/ (e.g., AndroidComputeResPathsTests.cs)
• Extend BaseTest, use MockBuildEngine — note: MockBuildEngine constructor accepts (TextWriter output, IList<BuildErrorEventArgs> errors = null, IList<BuildWarningEventArgs> warnings = null, IList<BuildMessageEventArgs> messages = null)
• TaskLoggingHelper needs a IBuildEngine and a task name string: new TaskLoggingHelper (engine, "Test")
• Use tabs for indentation, space before ( and [ (Mono style)
• No ! (null-forgiving operator) — declare temp fields as nullable instead
• SequencePointsMode enum is defined in Xamarin.Android.Tasks namespace (in Tasks/Aot.cs): None, Normal, Offline
• Create and clean up temp files for each test using [SetUp] / [TearDown]

Acceptance Criteria

• New file EnvironmentFilesParserTests.cs added in the Tasks test directory
• MONO_LOG_LEVEL detection tested
• MONO_GC_PARAMS detection tested, including XA2000 warning for old bridge
• MONO_DEBUG detection and sequence-points appending tested
• XA_HTTP_CLIENT_HANDLER_TYPE detection tested
• XA_BROKEN_EXCEPTION_TRANSITIONS filtering tested (flag set, line excluded from EnvironmentVariableLines)
• mono.enable_assembly_preload filtering tested (flag set, line excluded from EnvironmentVariableLines)
• AreBrokenExceptionTransitionsEnabled tested
• Null environments handled gracefully
• All existing tests still pass
• No new warnings introduced

Generated by Nightly Fix Finder for issue #11352 · ● 5.4M · ◷

• expires on May 22, 2026, 5:28 PM UTC