proposal-system/api/tests/ProposalSystem.Tests/Validators/CreateLineItemValidatorTests.cs

using FluentAssertions;
using ProposalSystem.Application.DTOs;
using ProposalSystem.Application.Validators;
using ProposalSystem.Domain.Entities;
using Xunit;

namespace ProposalSystem.Tests.Validators;

/// <summary>
/// Tests for CreateLineItemValidator — validates line item payloads.
/// </summary>
public class CreateLineItemValidatorTests
{
    private readonly CreateLineItemValidator _sut = new();

    [Fact(DisplayName = "Valid line item request passes validation")]
    public void ValidRequest_Passes()
    {
        var request = new CreateLineItemRequest(
            Description: "HVAC duct replacement",
            Quantity: 10,
            Unit: "linear ft",
            UnitPrice: 25.50m,
            TotalPrice: 255.00m,
            PricingMode: PricingMode.UnitPrice,
            SortOrder: 1,
            Source: LineItemSource.Manual
        );

        var result = _sut.Validate(request);

        result.IsValid.Should().BeTrue();
    }

    [Fact(DisplayName = "Empty description fails")]
    public void EmptyDescription_Fails()
    {
        var request = new CreateLineItemRequest("", 1, "each", null, 100m,
            PricingMode.TotalPrice, 1, LineItemSource.Manual);

        var result = _sut.Validate(request);

        result.IsValid.Should().BeFalse();
        result.Errors.Should().Contain(e => e.PropertyName == "Description");
    }

    [Fact(DisplayName = "Zero quantity fails")]
    public void ZeroQuantity_Fails()
    {
        var request = new CreateLineItemRequest("Work item", 0, "each", null, 100m,
            PricingMode.TotalPrice, 1, LineItemSource.Manual);

        var result = _sut.Validate(request);

        result.IsValid.Should().BeFalse();
        result.Errors.Should().Contain(e => e.PropertyName == "Quantity");
    }

    [Fact(DisplayName = "Negative quantity fails")]
    public void NegativeQuantity_Fails()
    {
        var request = new CreateLineItemRequest("Work item", -5, "each", null, 100m,
            PricingMode.TotalPrice, 1, LineItemSource.Manual);

        var result = _sut.Validate(request);

        result.IsValid.Should().BeFalse();
        result.Errors.Should().Contain(e => e.PropertyName == "Quantity");
    }

    [Fact(DisplayName = "Negative total price fails")]
    public void NegativeTotalPrice_Fails()
    {
        var request = new CreateLineItemRequest("Work item", 1, "each", null, -100m,
            PricingMode.TotalPrice, 1, LineItemSource.Manual);

        var result = _sut.Validate(request);

        result.IsValid.Should().BeFalse();
        result.Errors.Should().Contain(e => e.PropertyName == "TotalPrice");
    }

    [Fact(DisplayName = "Negative unit price fails")]
    public void NegativeUnitPrice_Fails()
    {
        var request = new CreateLineItemRequest("Work item", 1, "each", -10m, 100m,
            PricingMode.UnitPrice, 1, LineItemSource.Manual);

        var result = _sut.Validate(request);

        result.IsValid.Should().BeFalse();
        result.Errors.Should().Contain(e => e.PropertyName == "UnitPrice");
    }

    [Fact(DisplayName = "Null unit price is valid (lump sum pricing)")]
    public void NullUnitPrice_Passes()
    {
        var request = new CreateLineItemRequest("Work item", 1, "each", null, 100m,
            PricingMode.TotalPrice, 1, LineItemSource.Manual);

        var result = _sut.Validate(request);

        result.IsValid.Should().BeTrue();
    }

    [Fact(DisplayName = "Empty unit fails")]
    public void EmptyUnit_Fails()
    {
        var request = new CreateLineItemRequest("Work item", 1, "", null, 100m,
            PricingMode.TotalPrice, 1, LineItemSource.Manual);

        var result = _sut.Validate(request);

        result.IsValid.Should().BeFalse();
        result.Errors.Should().Contain(e => e.PropertyName == "Unit");
    }

    [Fact(DisplayName = "Negative sort order fails")]
    public void NegativeSortOrder_Fails()
    {
        var request = new CreateLineItemRequest("Work item", 1, "each", null, 100m,
            PricingMode.TotalPrice, -1, LineItemSource.Manual);

        var result = _sut.Validate(request);

        result.IsValid.Should().BeFalse();
        result.Errors.Should().Contain(e => e.PropertyName == "SortOrder");
    }
}