diff --git a/tests/Vantage.Core.Tests/Configuration/JsonConfigStoreTests.cs b/tests/Vantage.Core.Tests/Configuration/JsonConfigStoreTests.cs
new file mode 100644
index 0000000..aef5891
--- /dev/null
+++ b/tests/Vantage.Core.Tests/Configuration/JsonConfigStoreTests.cs
@@ -0,0 +1,63 @@
+using Vantage.Core.Configuration;
+using Vantage.Core.Models;
+using Xunit;
+
+namespace Vantage.Core.Tests.Configuration;
+
+public class JsonConfigStoreTests : IDisposable
+{
+    private readonly string tempDir = Path.Combine(Path.GetTempPath(), "vantage-tests-" + Guid.NewGuid().ToString("N"));
+
+    private string ConfigPath => Path.Combine(tempDir, "config.json");
+
+    [Fact]
+    public async Task LoadAsync_MissingFileReturnsEmptyConfig()
+    {
+        var store = new JsonConfigStore(ConfigPath);
+        var config = await store.LoadAsync();
+
+        Assert.Empty(config.Hosts);
+        Assert.Empty(config.HealthChecks);
+    }
+
+    [Fact]
+    public async Task SaveThenLoad_RoundTripsHostsAndChecks()
+    {
+        var store = new JsonConfigStore(ConfigPath);
+        var original = new VantageConfig
+        {
+            RefreshIntervalSeconds = 9,
+            Hosts = { new HostConfig { Name = "edge", Address = "10.0.0.1", Username = "root", AuthMethod = SshAuthMethod.PrivateKey } },
+            HealthChecks = { new HealthCheckConfig { Name = "web", Kind = HealthKind.Http, Target = "https://x" } }
+        };
+
+        await store.SaveAsync(original);
+        var loaded = await store.LoadAsync();
+
+        Assert.Equal(9, loaded.RefreshIntervalSeconds);
+        Assert.Single(loaded.Hosts);
+        Assert.Equal("edge", loaded.Hosts[0].Name);
+        Assert.Equal(SshAuthMethod.PrivateKey, loaded.Hosts[0].AuthMethod);
+        Assert.Equal(HealthKind.Http, loaded.HealthChecks[0].Kind);
+    }
+
+    [Fact]
+    public async Task SaveAsync_WritesEnumsAsStrings()
+    {
+        var store = new JsonConfigStore(ConfigPath);
+        await store.SaveAsync(new VantageConfig
+        {
+            Hosts = { new HostConfig { AuthMethod = SshAuthMethod.PrivateKey } }
+        });
+
+        var json = await File.ReadAllTextAsync(ConfigPath);
+        Assert.Contains("privateKey", json);
+        Assert.DoesNotContain("\"authMethod\": 0", json);
+    }
+
+    public void Dispose()
+    {
+        if (Directory.Exists(tempDir))
+            Directory.Delete(tempDir, recursive: true);
+    }
+}
diff --git a/tests/Vantage.Core.Tests/Docker/DockerTests.cs b/tests/Vantage.Core.Tests/Docker/DockerTests.cs
new file mode 100644
index 0000000..230e342
--- /dev/null
+++ b/tests/Vantage.Core.Tests/Docker/DockerTests.cs
@@ -0,0 +1,68 @@
+using Vantage.Core.Docker;
+using Vantage.Core.Models;
+using Vantage.Core.Tests.Fakes;
+using Xunit;
+
+namespace Vantage.Core.Tests.Docker;
+
+public class DockerTests
+{
+    private const string PsOutput =
+        "c1a2\tcaddy\tcaddy:2\trunning\tUp 6 days\n" +
+        "9f8e\tbackup\talpine:3.20\texited\tExited (0) 3 hours ago\n" +
+        "aa11\tpaused-svc\tredis:7\tpaused\tUp 2 hours (Paused)\n";
+
+    [Fact]
+    public void Parser_MapsFieldsAndStates()
+    {
+        var containers = DockerContainerParser.Parse(PsOutput);
+
+        Assert.Equal(3, containers.Count);
+        Assert.Equal("caddy", containers[0].Name);
+        Assert.Equal(ContainerState.Running, containers[0].State);
+        Assert.True(containers[0].IsRunning);
+        Assert.Equal(ContainerState.Exited, containers[1].State);
+        Assert.Equal(ContainerState.Paused, containers[2].State);
+    }
+
+    [Fact]
+    public async Task SshDockerProvider_ListParsesRunnerOutput()
+    {
+        var runner = new FakeSshCommandRunner(PsOutput);
+        var provider = new SshDockerProvider(runner);
+
+        var containers = await provider.ListContainersAsync(new HostConfig(), CancellationToken.None);
+
+        Assert.Equal(3, containers.Count);
+        Assert.Contains("docker ps -a", runner.Commands.Single());
+    }
+
+    [Fact]
+    public async Task SshDockerProvider_ExecuteBuildsRestartCommand()
+    {
+        var runner = new FakeSshCommandRunner(_ => "");
+        var provider = new SshDockerProvider(runner);
+
+        await provider.ExecuteAsync(new HostConfig(), DockerAction.Restart, "abc123", CancellationToken.None);
+
+        Assert.Equal("docker restart 'abc123'", runner.Commands.Single());
+    }
+
+    [Fact]
+    public async Task MockDockerProvider_StopThenStartTransitionsState()
+    {
+        var provider = new MockDockerProvider();
+        var host = new HostConfig { Id = "h1" };
+
+        var initial = await provider.ListContainersAsync(host, CancellationToken.None);
+        var running = initial.First(c => c.IsRunning);
+
+        await provider.ExecuteAsync(host, DockerAction.Stop, running.Id, CancellationToken.None);
+        var afterStop = await provider.ListContainersAsync(host, CancellationToken.None);
+        Assert.Equal(ContainerState.Exited, afterStop.First(c => c.Id == running.Id).State);
+
+        await provider.ExecuteAsync(host, DockerAction.Start, running.Id, CancellationToken.None);
+        var afterStart = await provider.ListContainersAsync(host, CancellationToken.None);
+        Assert.Equal(ContainerState.Running, afterStart.First(c => c.Id == running.Id).State);
+    }
+}