Add Elastic.Elasticsearch.TUnit — TUnit integration for ephemeral Elasticsearch clusters

[Mpdreamz]

Summary

Elastic.Elasticsearch.TUnit — a new package that integrates ephemeral Elasticsearch clusters with TUnit.

Define a cluster, write tests, and get a real Elasticsearch instance spun up automatically. No boilerplate, no custom test frameworks, no marker interfaces.

Minimal example — this is the entire setup

public class MyTestCluster() : ElasticsearchCluster("latest-9");

[ClassDataSource<MyTestCluster>(Shared = SharedType.Keyed, Key = nameof(MyTestCluster))]
public class MyTests(MyTestCluster cluster)
{
    [Test]
    public async Task InfoReturnsNodeName()
    {
        var info = await cluster.Client.InfoAsync();
        await Assert.That(info.Name).IsNotNull();
    }
}

The base class provides a default Client with debug mode enabled and per-request diagnostics routed to the currently executing test. Override Client when you need custom authentication, serialization, or connection settings.

What you get out of the box

• Sane defaults everywhere — one-liner cluster definition, built-in client with debug mode, automatic download/install/start/teardown
• Per-test output capture — each test's request/response diagnostics appear in that test's TUnit output via TestContext.Current, even though the client is shared across all tests. This means you can inspect individual test output in your IDE
• Bootstrap diagnostics that don't fight TUnit — cluster startup output bypasses TUnit's per-test capture and writes directly to the terminal so you can always see what Elasticsearch is doing during startup:
  • Interactive terminals — a periodic heartbeat every 5 seconds showing the cluster name, location, elapsed time, and the last Elasticsearch log line. Keeps your terminal clean while still showing progress during the 60+ second startup
  • CI / non-interactive — full verbose ANSI-colored output with per-node log lines, so you have the complete picture in CI logs
  • Configurable via ShowBootstrapDiagnostics (true = always full, false = silent, null = auto-detect)
• Bootstrap result always in TestContext — whether the cluster started successfully or failed, the result summary is written to TestContext.Current so it shows up in your IDE's test output. On failure, per-node diagnostics (started status, port, version, last exception) are included
• Version-skip and custom skip attributes — [SkipVersion("<8.0.0", "reason")] evaluates against the running cluster's actual version; extend SkipTestAttribute for arbitrary skip conditions
• Parallel limiting — [ParallelLimiter<ElasticsearchParallelLimit>] caps test concurrency per Environment.ProcessorCount
• Cluster sharing — TUnit's SharedType.Keyed means the cluster starts once and is shared across all test classes that reference the same key, with serialized startup across different cluster types

More involved example

public abstract class MyClusterBase : ElasticsearchCluster
{
    protected MyClusterBase() : base(new ElasticsearchConfiguration("latest-9")
    {
        ShowElasticsearchOutputAfterStarted = false,
    }) { }
}

public class TestCluster : MyClusterBase
{
    protected override void SeedCluster()
    {
        var response = Client.Info();
    }
}

[SkipVersion("<6.2.0", "")]
[ClassDataSource<TestCluster>(Shared = SharedType.Keyed, Key = nameof(TestCluster))]
public class SkippableTests(TestCluster cluster)
{
    [Test]
    public async Task SomeTest()
    {
        var info = await cluster.Client.InfoAsync();
        await Assert.That(info.IsValidResponse).IsTrue();
    }
}

Interactive output

Locally you will get progress updates every 5 seconds to see where it is in the bootstrapping without overwhelming the console.