Add cross-platform unit tests with MSTest framework

[Copilot]

Implementation Plan for Cross-Platform Unit Tests

• Create test project structure
  • Create /test/DemaConsulting.DotnetToolWrapper.Tests directory
  • Create test project file with MSTest framework
  • Add project reference to source project
  • Create Runner.cs helper class
• Implement unit tests
  • Test for missing DotnetToolWrapper.json file
  • Test for exit codes (0, 1, 42, 255)
  • Test for argument passing
  • Test for cross-platform compatibility
  • Test for unsupported target
  • Test for bad configuration
  • Test for GetOs, GetArchitecture, GetTarget methods
• Update solution file
  • Add test project to solution
• Update build workflow
  • Add Test job with matrix testing (windows, macOS, linux)
  • Keep Artifact Creation job on ubuntu-latest only
  • Add explicit permissions to workflow jobs for security
• Update .gitignore
  • Add common .NET build artifacts
• Run tests locally to verify functionality (All 11 tests passing on net8.0, net9.0, net10.0)
• Address code review feedback
  • Updated Runner to capture both stdout and stderr
  • Added using statement to properly dispose Process
  • Split tests into separate files (ProgramTests.cs for unit tests, IntegrationTests.cs for DLL execution tests)
  • Use COMSPEC environment variable for complete Windows shell path instead of just "cmd.exe"
• Security validation - All security issues resolved
• Implementation complete

Original prompt

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This section details on the original issue you should resolve

<issue_title>[Feature]: Cross-platform unit tests</issue_title>
<issue_description>### 🎯 Problem Statement

The project lacks unit tests.

💡 Proposed Solution

Add a unit test project under "/test/DemaConsulting.DotnetToolWrapper.Tests" folder with the following:

• Tests written using the AAA (Arrange-Act-Assert) pattern
• Using the MSTest framework
• The test project dependent on the DotnetToolWrapper source project and copying its assemblies
• A helper Runner.cs containing a Runner class
• Tests that:
  1. Create a temporary 'DotnetToolWrapper.json' file
  2. Use the Runner class to run 'dotnet' to execute 'DemaConsulting.DotnetToolWrapper.dll' with test arguments
• The tests should include such things as:
  • Verifying a missing DotnetToolWrapper.json results in the expected error
  • Verifying exit codes work (possibly by running the shell to exit with a test exit code)
  • Verifying arguments are passed (possibly by running the shell to echo the arguments)
  • Compatible with different operating systems (windows, macOS, linux)

The build.yaml should add a "Test" job to run the unit tests with matrix-test on windows, macOS, and linux; although the existing "Artifact Creation" job needs to only run on ubuntu-latest.

🔄 Alternatives Considered

No response

📝 Additional Context

The Runner class should be structured as follows:

/// <summary>
/// Program runner class
/// </summary>
internal static class Runner
{
    /// <summary>
    /// Run the specified program
    /// </summary>
    /// <param name="output">Program output</param>
    /// <param name="program">Program name</param>
    /// <param name="arguments">Program arguments</param>
    /// <returns>Program exit code</returns>
    /// <exception cref="InvalidOperationException">On program start error</exception>
    public static int Run(out string output, string program, params string[] arguments)
    {
        // Construct the start information
        var startInfo = new ProcessStartInfo(program)
        {
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false,
            CreateNoWindow = true
        };

        // Add the arguments
        foreach (var argument in arguments)
            startInfo.ArgumentList.Add(argument);

        // Start the process
        var process = Process.Start(startInfo) ??
                      throw new InvalidOperationException("Failed to start process");

        // Wait for the process to exit
        process.WaitForExit();

        // Save the output and return the exit code
        output = process.StandardOutput.ReadToEnd();
        return process.ExitCode;
    }
}

🤝 Contribution

• I would be willing to implement this feature</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [Feature]: Cross-platform unit tests #20

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[Malcolmnixon]

"cmd.exe" is not a complete path to the windows shell. Consider replacing this with using environment variables or some other more reliable way to get an absolute path to the shell program.

[Malcolmnixon]

@copilot Please try fixing this again - you encountered a failure last time because you got stuck in a loop forever failing to read CI workflow logs - do not try to read them when working on this.

[Copilot]

Fixed in commit 81f9cce. Changed GetShellProgram() to use the COMSPEC environment variable on Windows, which provides the full path to cmd.exe (typically C:\Windows\System32\cmd.exe), instead of just "cmd.exe".