CliFx/CliFx.Analyzers.Tests/SystemConsoleShouldBeAvoidedAnalyzerSpecs.cs

using CliFx.Analyzers.Tests.Utils;
using Microsoft.CodeAnalysis.Diagnostics;
using Xunit;

namespace CliFx.Analyzers.Tests;

public class SystemConsoleShouldBeAvoidedAnalyzerSpecs
{
    private static DiagnosticAnalyzer Analyzer { get; } =
        new SystemConsoleShouldBeAvoidedAnalyzer();

    [Fact]
    public void Analyzer_reports_an_error_if_a_command_calls_a_method_on_SystemConsole()
    {
        // Arrange
        // lang=csharp
        const string code = """
            [Command]
            public class MyCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console)
                {
                    Console.WriteLine("Hello world");
                    return default;
                }
            }
            """;

        // Act & assert
        Analyzer.Should().ProduceDiagnostics(code);
    }

    [Fact]
    public void Analyzer_reports_an_error_if_a_command_accesses_a_property_on_SystemConsole()
    {
        // Arrange
        // lang=csharp
        const string code = """
            [Command]
            public class MyCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console)
                {
                    Console.ForegroundColor = ConsoleColor.Black;
                    return default;
                }
            }
            """;

        // Act & assert
        Analyzer.Should().ProduceDiagnostics(code);
    }

    [Fact]
    public void Analyzer_reports_an_error_if_a_command_calls_a_method_on_a_property_of_SystemConsole()
    {
        // Arrange
        // lang=csharp
        const string code = """
            [Command]
            public class MyCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console)
                {
                    Console.Error.WriteLine("Hello world");
                    return default;
                }
            }
            """;

        // Act & assert
        Analyzer.Should().ProduceDiagnostics(code);
    }

    [Fact]
    public void Analyzer_does_not_report_an_error_if_a_command_interacts_with_the_console_through_IConsole()
    {
        // Arrange
        // lang=csharp
        const string code = """
            [Command]
            public class MyCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console)
                {
                    console.Output.WriteLine("Hello world");
                    return default;
                }
            }
            """;

        // Act & assert
        Analyzer.Should().NotProduceDiagnostics(code);
    }

    [Fact]
    public void Analyzer_does_not_report_an_error_if_IConsole_is_not_available_in_the_current_method()
    {
        // Arrange
        // lang=csharp
        const string code = """
            [Command]
            public class MyCommand : ICommand
            {
                public void SomeOtherMethod() => Console.WriteLine("Test");
            
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """;

        // Act & assert
        Analyzer.Should().NotProduceDiagnostics(code);
    }

    [Fact]
    public void Analyzer_does_not_report_an_error_if_a_command_does_not_access_SystemConsole()
    {
        // Arrange
        // lang=csharp
        const string code = """
            [Command]
            public class MyCommand : ICommand
            {
                public ValueTask ExecuteAsync(IConsole console)
                {
                    return default;
                }
            }
            """;

        // Act & assert
        Analyzer.Should().NotProduceDiagnostics(code);
    }
}