Inject IConsole into ValidatorRunner for testable console output

[Copilot]

ValidatorRunner wrote directly to Console.WriteLine/Console.Error, making stdout/stderr output untestable. Since System.CommandLine 2.0.6 removed IConsole, the abstraction is defined in-project.

Core changes

• IConsole — single interface with async WriteLineAsync(string) and WriteErrorLineAsync(string) methods
• SystemConsole — production impl delegating to Console.Out.WriteLineAsync / Console.Error.WriteLineAsync
• ValidatorRunner — IConsole console added as primary-constructor parameter; all three Console.* calls replaced:

  // before
  await Console.Error.WriteLineAsync($"No .slnx files found for input: {options.Input}");
  Console.WriteLine($"SonarQube report written to: ...");
  
  // after
  await console.WriteErrorLineAsync($"No .slnx files found for input: {options.Input}");
  await console.WriteLineAsync($"SonarQube report written to: ...");

• Program.cs — IConsole registered as new SystemConsole() singleton in DI

Test infrastructure

• FakeConsole — in-memory impl with List<string> OutputLines and List<string> ErrorLines properties for easy assertion
• MockFileSystem — GetFileSize returns 0; no stream-wrapping complexity
• ValidatorRunnerTests — _console is a shared instance field (fresh per test via NUnit's per-test instantiation); factory helpers are instance methods that use _console; three new tests cover the "no files found" error path and the SonarQube/SARIF confirmation messages

Original prompt

Goal

Make ValidatorRunner testable by replacing direct Console.WriteLine / Console.Error.WriteLineAsync calls with an injected System.CommandLine.IConsole abstraction. Add the missing tests that verify console output. Update all existing test helpers that construct ValidatorRunner so they compile and pass.

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1. Change ValidatorRunner – inject IConsole

File: src/SLNX-validator/ValidatorRunner.cs

Add IConsole console as a primary-constructor parameter (after IFileSystem fileSystem).

Replace:

await Console.Error.WriteLineAsync($"No .slnx files found for input: {options.Input}");

with:

console.Error.Write($"No .slnx files found for input: {options.Input}{Environment.NewLine}");

Replace both:

Console.WriteLine($"SonarQube report written to: {options.SonarqubeReportPath} ({size} bytes)");

and:

Console.WriteLine($"SARIF report written to: {options.SarifReportPath} ({size} bytes)");

with:

console.Out.Write($"SonarQube report written to: {options.SonarqubeReportPath} ({size} bytes){Environment.NewLine}");

and:

console.Out.Write($"SARIF report written to: {options.SarifReportPath} ({size} bytes){Environment.NewLine}");

Add the using: using System.CommandLine;

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2. Register IConsole in DI – Program.cs

File: src/SLNX-validator/Program.cs

In the ServiceCollection setup, add:

.AddSingleton<IConsole>(new SystemConsole())

SystemConsole is the concrete type in System.CommandLine that wraps the real Console.

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3. Update ValidatorRunnerTests.cs

File: tests/SLNX-validator.Tests/ValidatorRunnerTests.cs

3a. Add helper to create a test console

At the top of the class add a private helper that creates a simple in-memory console for testing. System.CommandLine ships a TestConsole class; use that.

Add using: using System.CommandLine;

3b. Update CreateRunner and CreateRunnerWithSlnx

Both factory methods must accept an optional IConsole? console = null parameter and pass console ?? new TestConsole() as the last argument to the ValidatorRunner constructor.

3c. Add missing tests for console output

Add a new test region #region RunAsync – console output with the following tests (no more than needed):

[Test]
public async Task RunAsync_NoFilesFound_WritesErrorToConsole()
{
    // Arrange
    var console = new TestConsole();
    var runner = CreateRunner(new MockFileSystem(), console: console);

    // Act
    await runner.RunAsync(Options("nonexistent.slnx"), CancellationToken.None);

    // Assert
    console.Error.ToString().Should().Contain("No .slnx files found for input: nonexistent.slnx");
}

[Test]
public async Task RunAsync_SonarqubeReportPath_WritesConfirmationToConsole()
{
    // Arrange
    var slnxPath = Path.GetFullPath("test.slnx");
    var console = new TestConsole();
    var runner = CreateRunnerWithSlnx(slnxPath, "<Solution />", console: console);
    var options = new ValidatorRunnerOptions(slnxPath, SonarqubeReportPath: "report.xml",
        ContinueOnError: false, RequiredFilesPattern: null, WorkingDirectory: ".");

    // Act
    await runner.RunAsync(options, CancellationToken.None);

    // Assert
    console.Out.ToString().Should().Contain("SonarQube report written to: report.xml");
}

[Test]
public async Task RunAsync_SarifReportPath_WritesConfirmationToConsole()
{
    // Arrange
    var slnxPath = Path.GetFullPath("test.slnx");
    var console = new TestConsole();
    var runner = CreateRunnerWithSlnx(slnxPath, "<Solution />", console: console);
    var options = new ValidatorRunnerOptions(slnxPath, SonarqubeReportPath: null,
        ContinueOnError: false, RequiredFilesPattern: null, WorkingDirectory: ".",
        SarifReportPath: "report.sarif");

    // Act
    await runner.RunAsync(options, CancellationToken.None);

    // Assert
    console.Out.ToString().Should().Contain("SARIF report written to: report.sarif");
}

Important: TestConsole from System.CommandLine has .Error and .Out as IStandardStreamWriter. Use .ToString() on them to get the written text.

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Notes

• Do not add new NuGet packages. System.CommandLine is already referenced in src/SLNX-validator/SLNX-validator.csproj and the test project references the main project, so TestConsole is already available in tests.
• Keep all existing tests passing — only the two factory method signatures change (adding optional IConsole? console parameter).
• Do not write more tests than listed above.

The following is the prior conversation context from the user's chat exploration (may be truncated):

User: We missen wat tests voor @304NotModified/SLNX-validator/files/src/SLNX-validator/ValidatorRunner.cs. maar we missen ook een abstractie voor de console. Is daar een goede package voor of kunnen we beter een eigen schrijven?

Assistant: Goede bevindingen! Het project gebruikt al System.CommandLine (...

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