test(app): add docker and main window view model tests

tests/Vantage.App.Tests/MainWindowViewModelTests.cs

@@ -0,0 +1,70 @@
+using Vantage.App.Tests.Fakes;
+using Vantage.App.ViewModels;
+using Vantage.Core.Configuration;
+using Vantage.Core.Docker;
+using Vantage.Core.Health;
+using Vantage.Core.Metrics;
+using Xunit;
+
+namespace Vantage.App.Tests;
+
+public class MainWindowViewModelTests
+{
+    private static IConfigStore EmptyStore() =>
+        new JsonConfigStore(Path.Combine(Path.GetTempPath(), "vantage-vm-" + Guid.NewGuid().ToString("N"), "config.json"));
+
+    private static MainWindowViewModel Build(IMetricsProvider metrics, IHealthChecker? health = null) =>
+        new(metrics, new MockDockerProvider(), health ?? new HealthChecker(new HttpClient()), EmptyStore());
+
+    [Fact]
+    public async Task InitializeAsync_FallsBackToDemoDataWhenConfigEmpty()
+    {
+        var viewModel = Build(new MockMetricsProvider());
+
+        await viewModel.InitializeAsync();
+
+        Assert.NotEmpty(viewModel.Hosts);
+        Assert.NotEmpty(viewModel.HealthChecks);
+        Assert.NotNull(viewModel.SelectedHost);
+        Assert.Same(viewModel.Hosts[0].Config, viewModel.Docker.Host);
+    }
+
+    [Fact]
+    public async Task RefreshSelectedHostAsync_PopulatesMetricsAndHistory()
+    {
+        var viewModel = Build(new MockMetricsProvider());
+        await viewModel.InitializeAsync();
+
+        await viewModel.RefreshSelectedHostAsync(CancellationToken.None);
+
+        Assert.True(viewModel.SelectedHost!.IsOnline);
+        Assert.NotEmpty(viewModel.SelectedHost.CpuPoints);
+        Assert.StartsWith("Updated", viewModel.StatusLine);
+    }
+
+    [Fact]
+    public async Task RefreshSelectedHostAsync_MarksHostUnreachableOnFailure()
+    {
+        var viewModel = Build(new ThrowingMetricsProvider());
+        await viewModel.InitializeAsync();
+
+        await viewModel.RefreshSelectedHostAsync(CancellationToken.None);
+
+        Assert.False(viewModel.SelectedHost!.IsOnline);
+        Assert.Equal(ThrowingMetricsProvider.Message, viewModel.SelectedHost.LastError);
+        Assert.Contains(ThrowingMetricsProvider.Message, viewModel.StatusLine);
+    }
+
+    [Fact]
+    public async Task RunAllHealthAsync_RunsEveryConfiguredCheck()
+    {
+        var health = new FakeHealthChecker(Vantage.Core.Models.HealthCheckResult.Up(5, "ok"));
+        var viewModel = Build(new MockMetricsProvider(), health);
+        await viewModel.InitializeAsync();
+
+        await viewModel.RunAllHealthAsync(CancellationToken.None);
+
+        Assert.Equal(viewModel.HealthChecks.Count, health.Calls);
+        Assert.All(viewModel.HealthChecks, check => Assert.StartsWith("Up", check.StatusText));
+    }
+}