Teamup/tests/TeamUp.ArchitectureTests/ModuleBoundaryTests.cs

using Xunit;

namespace TeamUp.ArchitectureTests;

/// <summary>
/// Encodes the non-negotiable "no cross-module table access" discipline as build-time rules.
/// The <c>internal</c>-per-assembly design is the hard wall (another module's entities/DbContext
/// aren't even visible); these reference checks guard the gate the compiler can't: a module
/// adding a project reference to another module, or to shared Infrastructure/Bootstrap/hosts.
/// </summary>
public sealed class ModuleBoundaryTests
{
    [Fact]
    public void Modules_do_not_reference_each_other()
    {
        foreach (var module in ArchitectureFixture.ModuleAssemblies)
        {
            var references = module.ReferencedAssemblyNames();

            foreach (var other in ArchitectureFixture.ModuleAssemblies)
            {
                if (ReferenceEquals(module, other))
                {
                    continue;
                }

                var otherName = other.GetName().Name!;
                Assert.False(
                    references.Contains(otherName),
                    $"{module.GetName().Name} must not reference module {otherName} — collaborate via abstractions in DI.");
            }
        }
    }

    [Fact]
    public void Modules_do_not_reference_infrastructure_bootstrap_or_hosts()
    {
        string[] forbidden = ["TeamUp.Infrastructure", "TeamUp.Bootstrap", "TeamUp.Web", "TeamUp.Worker"];

        foreach (var module in ArchitectureFixture.ModuleAssemblies)
        {
            var references = module.ReferencedAssemblyNames();

            foreach (var name in forbidden)
            {
                Assert.False(
                    references.Contains(name),
                    $"{module.GetName().Name} must not reference {name} — only SharedKernel is allowed.");
            }
        }
    }

    [Fact]
    public void Every_module_references_sharedkernel()
    {
        // Sanity: each module genuinely sits on the kernel (uses IModule / ModulePing).
        foreach (var module in ArchitectureFixture.ModuleAssemblies)
        {
            Assert.Contains("TeamUp.SharedKernel", module.ReferencedAssemblyNames());
        }
    }

    [Fact]
    public void SharedKernel_references_no_teamup_projects()
    {
        var teamUpReferences = ArchitectureFixture.SharedKernel.ReferencedAssemblyNames()
            .Where(name => name.StartsWith("TeamUp.", StringComparison.Ordinal));

        Assert.Empty(teamUpReferences);
    }

    [Fact]
    public void Infrastructure_references_only_sharedkernel_among_teamup_projects()
    {
        var teamUpReferences = ArchitectureFixture.Infrastructure.ReferencedAssemblyNames()
            .Where(name => name.StartsWith("TeamUp.", StringComparison.Ordinal))
            .OrderBy(name => name, StringComparer.Ordinal)
            .ToArray();

        Assert.Equal(["TeamUp.SharedKernel"], teamUpReferences);
    }
}