Rig.TUnit.Docker 0.1.0-beta.2

Rig.TUnit.Docker

Generic Testcontainers-backed ContainerFixture for bespoke / third-party / exploratory container testing. Escape hatch when no provider-specific fixture fits.

What this package is

A general-purpose container fixture for situations where none of the provider-specific packages (SqlServer, Redis, Kafka, …) apply. Spins an arbitrary image through Testcontainers, exposes the raw IContainer for bespoke control, and wires the same IsolationKey-based naming convention every other fixture uses.

Use when you are prototyping against a third-party service without a Rig.TUnit package, writing a custom test-harness container, or exploring a new backend before graduating to its own provider package.

When to use it

• Testing a new third-party service that has no Rig.TUnit package yet.
• Custom test-harness containers (your own Docker image).
• Exploratory testing before a full provider package lands.
• Not for: production-shape testing of services with a dedicated Rig.TUnit package — use that instead.

Prerequisites

• .NET 10 SDK
• Docker Desktop / Colima
• Testcontainers (transitive)

Quick start

using Rig.TUnit.Docker.Fixtures;

await using var fx = new ContainerFixture(
 image: "alpine:3",
 env: new Dictionary<string, string> { ["FOO"] = "bar" },
 exposedPorts: new[] { 8080 });
await fx.InitializeAsync();

Options

Fixture + helper APIs

• Rig.TUnit.Docker.Fixtures.ContainerFixture
• Rig.TUnit.Docker.Options.DockerFixtureOptions
• Rig.TUnit.Docker.Builder.DockerRigBuilder

Per-test isolation

Each ContainerFixture owns its container and network. Container names include the IsolationKey suffix so parallel tests do not collide.

Parallelism + performance

• First-run pull: dominated by image size (alpine:3 ~8 MB).
• Warm startup: seconds (image-specific).
• Parallelism: bounded by Docker daemon capacity.

Troubleshooting

• Container exits immediately — check logs via fx.Container.GetLogsAsync(); the fixture surfaces them for diagnosis.
• Port conflicts — Testcontainers allocates ephemeral host ports; fixed-port usage breaks parallelism.

See .

Provider quirks + edge cases

• Docker-in-Docker is supported (Testcontainers's tc.host resolution handles CI nesting), but port mapping differs — use fx.Container.GetMappedPublicPort(port) for reliability.
• Ductus.FluentDocker is kept as a fallback escape hatch if the native Testcontainers compose backend regresses; activation criteria are documented per-incident.

Benchmarks

See ; baseline in benchmarks/baseline-005.json.

Related docs

License

MIT. See .