diff --git a/tests/Vantage.App.Tests/DockerViewModelTests.cs b/tests/Vantage.App.Tests/DockerViewModelTests.cs
new file mode 100644
index 0000000..c788f68
--- /dev/null
+++ b/tests/Vantage.App.Tests/DockerViewModelTests.cs
@@ -0,0 +1,47 @@
+using Vantage.App.ViewModels;
+using Vantage.Core.Docker;
+using Vantage.Core.Models;
+using Xunit;
+
+namespace Vantage.App.Tests;
+
+public class DockerViewModelTests
+{
+    [Fact]
+    public async Task RefreshAsync_PopulatesContainersForHost()
+    {
+        var viewModel = new DockerViewModel(new MockDockerProvider());
+        viewModel.SetHost(new HostConfig { Id = "h1" });
+
+        await viewModel.RefreshAsync(CancellationToken.None);
+
+        Assert.NotEmpty(viewModel.Containers);
+    }
+
+    [Fact]
+    public async Task RefreshAsync_WithoutHostDoesNothing()
+    {
+        var viewModel = new DockerViewModel(new MockDockerProvider());
+
+        await viewModel.RefreshAsync(CancellationToken.None);
+
+        Assert.Empty(viewModel.Containers);
+    }
+
+    [Fact]
+    public async Task StopCommand_TransitionsSelectedContainerToExited()
+    {
+        var viewModel = new DockerViewModel(new MockDockerProvider());
+        viewModel.SetHost(new HostConfig { Id = "h2" });
+        await viewModel.RefreshAsync(CancellationToken.None);
+
+        var running = viewModel.Containers.First(c => c.IsRunning);
+        viewModel.SelectedContainer = running;
+
+        await viewModel.StopCommand.ExecuteAsync(running);
+
+        var reloaded = viewModel.Containers.First(c => c.Id == running.Id);
+        Assert.Equal(ContainerState.Exited, reloaded.State);
+        Assert.False(reloaded.IsRunning);
+    }
+}
diff --git a/tests/Vantage.App.Tests/MainWindowViewModelTests.cs b/tests/Vantage.App.Tests/MainWindowViewModelTests.cs
new file mode 100644
index 0000000..7fae366
--- /dev/null
+++ b/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));
+    }
+}
diff --git a/tests/Vantage.App.Tests/ViewModelBindingTests.cs b/tests/Vantage.App.Tests/ViewModelBindingTests.cs
new file mode 100644
index 0000000..3c453cc
--- /dev/null
+++ b/tests/Vantage.App.Tests/ViewModelBindingTests.cs
@@ -0,0 +1,62 @@
+using Vantage.App.Tests.Fakes;
+using Vantage.App.ViewModels;
+using Vantage.Core.Models;
+using Xunit;
+
+namespace Vantage.App.Tests;
+
+public class ViewModelBindingTests
+{
+    [Fact]
+    public void HostViewModel_ApplyMetricsUpdatesTextsAndHistory()
+    {
+        var host = new HostViewModel(new HostConfig { Name = "node", Address = "10.0.0.5", Username = "root", Port = 22 }, historyLength: 10);
+
+        host.ApplyMetrics(new HostMetrics
+        {
+            CpuUsagePercent = 42.5,
+            MemoryUsedBytes = 4L * 1024 * 1024 * 1024,
+            MemoryTotalBytes = 8L * 1024 * 1024 * 1024,
+            DiskUsedBytes = 50L * 1024 * 1024 * 1024,
+            DiskTotalBytes = 100L * 1024 * 1024 * 1024,
+            Load1 = 0.8,
+            Load5 = 0.6,
+            Load15 = 0.4,
+            Uptime = TimeSpan.FromHours(50)
+        });
+
+        Assert.Equal(42.5, host.CpuUsagePercent);
+        Assert.Equal(50.0, host.MemoryUsedPercent);
+        Assert.Single(host.CpuPoints);
+        Assert.Equal("4.0 GiB / 8.0 GiB", host.MemoryText);
+        Assert.True(host.IsOnline);
+        Assert.Equal("node", host.Name);
+        Assert.Equal("root@10.0.0.5:22", host.Endpoint);
+    }
+
+    [Fact]
+    public void HostViewModel_ApplyErrorMarksOffline()
+    {
+        var host = new HostViewModel(new HostConfig { Name = "node" }, historyLength: 10);
+
+        host.ApplyError("connection refused");
+
+        Assert.False(host.IsOnline);
+        Assert.Equal("connection refused", host.LastError);
+        Assert.Equal("Unreachable", host.StatusText);
+    }
+
+    [Fact]
+    public async Task HealthCheckViewModel_RunAppliesResult()
+    {
+        var config = new HealthCheckConfig { Name = "web", Kind = HealthKind.Http, Target = "https://x" };
+        var checker = new FakeHealthChecker(HealthCheckResult.Up(12.4, "HTTP 200 OK"));
+        var viewModel = new HealthCheckViewModel(config, checker);
+
+        await viewModel.RunCommand.ExecuteAsync(null);
+
+        Assert.Equal(HealthStatus.Up, viewModel.Status);
+        Assert.StartsWith("Up", viewModel.StatusText);
+        Assert.Equal("12 ms", viewModel.LatencyText);
+    }
+}