feat(columnstate): scaffold tests

tests/DynamicTreeDataGrid.Tests/Columns/DynamicColumnListTests/ColumnStates.cs

@@ -0,0 +1,51 @@
+using DynamicTreeDataGrid.Columns;
+using DynamicTreeDataGrid.State;
+
+using Microsoft.Reactive.Testing;
+
+namespace DynamicTreeDataGrid.Tests.Columns.DynamicColumnListTests;
+
+public class ColumnStates {
+    private readonly TestScheduler _scheduler = new();
+    private readonly DynamicColumnList<TestPerson> _list = [];
+
+    private readonly List<ColumnState> _loadedStates = [
+        new("Id") { Index = 2, Visible = true },
+        new("Name") { Index = 0, Visible = true },
+        new("Date-of-Birth") { Index = 1, Visible = true },
+    ];
+
+    [Before(Test)]
+    public async Task Setup() {
+        await Task.CompletedTask;
+        // Build the collection with specific indexes
+        _list.Insert(0, new DynamicTextColumn<TestPerson, int>("Id", "Id", person => person.Id));
+        _list.Insert(1, new DynamicTextColumn<TestPerson, string>("Name", "Name", person => person.Name));
+        _list.Insert(2,
+            new DynamicTextColumn<TestPerson, DateTime>("Date-of-Birth", "DoB", person => person.DateOfBirth));
+    }
+
+    [After(Test)]
+    public async Task CleanupAfterTests() { await Task.CompletedTask; }
+
+    [Test]
+    public async Task Default_Collection_State() {
+        await Assert.That(_list.Count).IsEqualTo(3);
+
+        // Check that all items are in the right order and visible
+        await Assert.That(_list[0].Name).IsEqualTo("Id");
+        await Assert.That(_list[0].Visible).IsEqualTo(true);
+        await Assert.That(_list[1].Name).IsEqualTo("Name");
+        await Assert.That(_list[1].Visible).IsEqualTo(true);
+        await Assert.That(_list[2].Name).IsEqualTo("Date-of-Birth");
+        await Assert.That(_list[2].Visible).IsEqualTo(true);
+    }
+
+    [Test]
+    public async Task GetColumnStates_ReturnsAllStates() {
+        var result = _list.GetColumnStates();
+
+        // Check that all items are in the right order and visible
+        await Assert.That(result.Count()).IsEqualTo(3);
+    }
+}