junction/tests/Junction.Tests/Unit/MachineSnapshotTests.cs

using System;
using System.Collections.Generic;
using Junction.Domain.Models;
using Xunit;

namespace Junction.Tests.Unit
{
    public class MachineSnapshotTests
    {
        private static DataItem Item(string id, string name = "n", string value = "v") =>
            new DataItem(id, name, value, "Sample", DateTimeOffset.UtcNow);

        [Fact]
        public void Ctor_HoldsValues()
        {
            var machineId = Guid.NewGuid();
            var at = DateTimeOffset.UtcNow;
            var items = new[] { Item("a"), Item("b") };

            var snap = new MachineSnapshot(machineId, at, ConnectionState.Connected, items);

            Assert.Equal(machineId, snap.MachineId);
            Assert.Equal(at, snap.CapturedAt);
            Assert.Equal(ConnectionState.Connected, snap.ConnectionState);
            Assert.Equal(2, snap.Items.Count);
        }

        [Fact]
        public void Ctor_NullItems_DefaultsToEmptyNeverNull()
        {
            var snap = new MachineSnapshot(Guid.NewGuid(), DateTimeOffset.UtcNow, ConnectionState.Unknown, null);

            Assert.NotNull(snap.Items);
            Assert.Empty(snap.Items);
        }

        [Fact]
        public void IsEmpty_TrueWhenZeroItems()
        {
            var snap = new MachineSnapshot(Guid.NewGuid(), DateTimeOffset.UtcNow, ConnectionState.Connected, null);
            Assert.True(snap.IsEmpty);
        }

        [Fact]
        public void IsEmpty_FalseWhenHasItems()
        {
            var snap = new MachineSnapshot(
                Guid.NewGuid(), DateTimeOffset.UtcNow, ConnectionState.Connected, new[] { Item("a") });
            Assert.False(snap.IsEmpty);
        }

        [Fact]
        public void TryGetItem_ReturnsItem_WhenPresent()
        {
            var snap = new MachineSnapshot(
                Guid.NewGuid(), DateTimeOffset.UtcNow, ConnectionState.Connected,
                new[] { Item("temp", "Temperature", "42") });

            var found = snap.TryGetItem("temp");

            Assert.NotNull(found);
            Assert.Equal("Temperature", found!.Name);
            Assert.Equal("42", found.Value);
        }

        [Fact]
        public void TryGetItem_ReturnsNull_WhenMissing()
        {
            var snap = new MachineSnapshot(
                Guid.NewGuid(), DateTimeOffset.UtcNow, ConnectionState.Connected, new[] { Item("a") });

            Assert.Null(snap.TryGetItem("nope"));
        }

        [Fact]
        public void TryGetItem_ReturnsNull_WhenIdNull()
        {
            var snap = new MachineSnapshot(
                Guid.NewGuid(), DateTimeOffset.UtcNow, ConnectionState.Connected, new[] { Item("a") });

            Assert.Null(snap.TryGetItem(null!));
        }

        [Fact]
        public void Properties_AreGetOnly()
        {
            var props = typeof(MachineSnapshot).GetProperties();
            Assert.All(props, p => Assert.Null(p.SetMethod));
        }
    }
}