Just.Railway/Raliway.Tests/Results/GeneralUsage.cs

namespace Raliway.Tests.Results;

public class GeneralUsage
{
    [Fact]
    public void TwoResultCombination_WhenThereIsAnError()
    {
        // Given
        var result1 = Result.Success(1);
        var result2 = Result.Failure(Error.New("some error"));
        // When
        var result = Result.Combine(result1, result2);
        // Then
        Assert.True(result.IsFailure);
        Assert.Equal(result2.Error, result.Error);
    }
    [Fact]
    public void TwoResultCombination_WhenThereAreTwoErrors()
    {
        // Given
        var result1 = Result.Failure<byte>(Error.New("1"));
        var result2 = Result.Failure(Error.New("2"));
        // When
        var result = Result.Combine(result1, result2);
        // Then
        Assert.True(result.IsFailure);
        Assert.Equal(result1.Error + result2.Error, result.Error);
    }
    [Fact]
    public void TwoResultCombination_WhenThereIsNoError()
    {
        // Given
        var result1 = Result.Success(1);
        var result2 = Result.Success(3.14);
        // When
        var result = Result.Combine(result1, result2);
        // Then
        Assert.True(result.IsSuccess);
    }
    [Fact]
    public void ThreeResultCombination_WhenThereIsAnError()
    {
        // Given
        var result1 = Result.Success(1);
        var result2 = Result.Success(3.14);
        var result3 = Result.Failure(Error.New("some error"));
        // When
        Result<(int, double)> result = Result.Combine(result1, result2, result3);
        // Then
        Assert.True(result.IsFailure);
        Assert.Equal(result3.Error, result.Error);
    }
    [Fact]
    public void ThreeResultCombination_WhenThereAreTwoErrors()
    {
        // Given
        var result1 = Result.Failure<int?>(Error.New("1"));
        var result2 = Result.Success(3.14);
        var result3 = Result.Failure(Error.New("3"));
        // When
        Result<(int?, double)> result = Result.Combine(result1, result2, result3);
        // Then
        Assert.True(result.IsFailure);
        Assert.Equal(result1.Error + result3.Error, result.Error);
    }
    [Fact]
    public void ThreeResultCombination_WhenThereIsNoError()
    {
        // Given
        var result1 = Result.Success(1);
        var result2 = Result.Success(3.14);
        var result3 = Result.Success();
        // When
        var result = Result.Combine(result1, result2, result3);
        // Then
        Assert.True(result.IsSuccess);
    }

    [Fact]
    public void ChainedResultExtensions_WhenThereIsNoError()
    {
        // Given

        // When
        var result = Result.Success()
            .Append(() => Result.Success(1))
            .Append("test")
            .Map((i, s) => $"{s}_{i}")
            .Append("some")
            .Bind((s1, s2) => Result.Success(string.Join(';', s1, s2)))
            .Match(
                onSuccess: s => s.ToUpper(),
                onFailure: _ =>
                {
                    Assert.Fail();
                    return "";
                }
            );
        
        Assert.Equal("TEST_1;SOME", result);
    }

    [Fact]
    public void ChainedResultExtensions_WhenThereIsAnError()
    {
        // Given
        
        // When
        var error = Error.New("test");


        var result = Result.Success()
            .Append(() => Result.Failure<int>(error))
            .Append("test")
            .Map((i, s) =>
            {
                Assert.Fail();
                return Result.Success("");
            })
            .Append("some")
            .Bind((s1, s2) => 
            {
                Assert.Fail();
                return Result.Success("");
            })
            .Match(
                onSuccess: _ => 
                {
                    Assert.Fail();
                    return "";
                },
                onFailure: err =>
                {
                    Assert.Equal(error, err);
                    return "satisfied";
                }
            );
        
        // Then
        Assert.Equal("satisfied", result);
    }
}