CliFx/CliFx.Analyzers.Tests/ParameterMustHaveValidConverterAnalyzerSpecs.cs

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

namespace CliFx.Analyzers.Tests;

public class ParameterMustHaveValidConverterAnalyzerSpecs
{
    private static DiagnosticAnalyzer Analyzer { get; } = new ParameterMustHaveValidConverterAnalyzer();

    [Fact]
    public void Analyzer_reports_an_error_if_a_parameter_has_a_converter_that_does_not_derive_from_BindingConverter()
    {
        // Arrange
        // language=cs
        const string code =
            """
            public class MyConverter
            {
                public string Convert(string rawValue) => rawValue;
            }
            
            [Command]
            public class MyCommand : ICommand
            {
                [CommandParameter(0, Converter = typeof(MyConverter))]
                public string Foo { get; set; }
            
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """;

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

    [Fact]
    public void Analyzer_reports_an_error_if_a_parameter_has_a_converter_that_does_not_derive_from_a_compatible_BindingConverter()
    {
        // Arrange
        // language=cs
        const string code =
            """
            public class MyConverter : BindingConverter<int>
            {
                public override int Convert(string rawValue) => 42;
            }
            
            [Command]
            public class MyCommand : ICommand
            {
                [CommandParameter(0, Converter = typeof(MyConverter))]
                public string Foo { get; set; }
            
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """;


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

    [Fact]
    public void Analyzer_does_not_report_an_error_if_a_parameter_has_a_converter_that_derives_from_a_compatible_BindingConverter()
    {
        // Arrange
        // language=cs
        const string code =
            """
            public class MyConverter : BindingConverter<string>
            {
                public override string Convert(string rawValue) => rawValue;
            }
            
            [Command]
            public class MyCommand : ICommand
            {
                [CommandParameter(0, Converter = typeof(MyConverter))]
                public string Foo { get; set; }
            
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """;

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

    [Fact]
    public void Analyzer_does_not_report_an_error_if_a_nullable_parameter_has_a_converter_that_derives_from_a_compatible_BindingConverter()
    {
        // Arrange
        // language=cs
        const string code =
            """
            public class MyConverter : BindingConverter<int>
            {
                public override int Convert(string rawValue) => 42;
            }
            
            [Command]
            public class MyCommand : ICommand
            {
                [CommandOption("foo", Converter = typeof(MyConverter))]
                public int? Foo { get; set; }
            
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """;

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

    [Fact]
    public void Analyzer_does_not_report_an_error_if_a_non_scalar_parameter_has_a_converter_that_derives_from_a_compatible_BindingConverter()
    {
        // Arrange
        // language=cs
        const string code =
            """
            public class MyConverter : BindingConverter<string>
            {
                public override string Convert(string rawValue) => rawValue;
            }
            
            [Command]
            public class MyCommand : ICommand
            {
                [CommandParameter(0, Converter = typeof(MyConverter))]
                public IReadOnlyList<string> Foo { get; set; }
            
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """;

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

    [Fact]
    public void Analyzer_does_not_report_an_error_if_a_parameter_does_not_have_a_converter()
    {
        // Arrange
        // language=cs
        const string code =
            """
            [Command]
            public class MyCommand : ICommand
            {
                [CommandParameter(0)]
                public string Foo { get; set; }
            
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """;

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

    [Fact]
    public void Analyzer_does_not_report_an_error_on_a_property_that_is_not_a_parameter()
    {
        // Arrange
        // language=cs
        const string code =
            """
            [Command]
            public class MyCommand : ICommand
            {
                public string Foo { get; set; }
            
                public ValueTask ExecuteAsync(IConsole console) => default;
            }
            """;

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