Rig.TUnit.Databases.NoSql.Mongo 0.1.0-beta.2

Rig.TUnit.Databases.NoSql.Mongo

Testcontainers-backed MongoDB fixture with CollectionPerTestHelper and BsonDiff.

What this package is

The Rig.TUnit MongoDB provider. MongoFixture spins MongoDB via Testcontainers and exposes an IMongoClient + default-database. Two helpers solve the common pain points: CollectionPerTestHelper owns a per-test collection scoped by IsolationKey and drops it on disposal, and BsonDiff performs a structural diff between expected / actual documents with the usual system-field scrub list.

When to use it

• Integration tests targeting MongoDB-specific features (change streams, $lookup, text indexes, transactions with replica set).
• Asserting document shape with tolerance for _id / ts drift.
• Not for: unit tests — MongoDB's in-memory driver Mongo2Go is faster but produces different wire errors from the real server.

Prerequisites

• .NET 10 SDK
• Docker Desktop / Colima (MongoDB image ~200 MB)
• MongoDB.Driver 3.x (transitive)

Quick start

using MongoDB.Bson;
using Rig.TUnit.Core.Helpers;
using Rig.TUnit.Databases.NoSql.Mongo.Fixtures;
using Rig.TUnit.Databases.NoSql.Mongo.Helpers;

await using var fx = new MongoFixture();
await fx.InitializeAsync();

await using var scope = new CollectionPerTestHelper(
 fx.Database, IsolationKey.FromExecutionContext());
var orders = scope.GetCollection<BsonDocument>();

Options

Fixture + helper APIs

• Rig.TUnit.Databases.NoSql.Mongo.Fixtures.MongoFixture
• Rig.TUnit.Databases.NoSql.Mongo.Options.MongoFixtureOptions
• Rig.TUnit.Databases.NoSql.Mongo.Builder.MongoRigBuilder
• Rig.TUnit.Databases.NoSql.Mongo.Helpers.CollectionPerTestHelper
• Rig.TUnit.Databases.NoSql.Mongo.Assertions.BsonDiff

Per-test isolation

CollectionPerTestHelper names collections {logical}_{IsolationKey:short} and calls Database.DropCollectionAsync on DisposeAsync. Fully parallel-safe.

Parallelism + performance

• First-run pull: ~15 s.
• Warm startup: ~2 s.
• Per-test collection create + drop: ~30 ms.
• Parallelism: 8+ concurrent tests — collection-level isolation works well.

Troubleshooting

• Transactions fail with Standalone servers do not support — set ReplicaSetName = "rs0"; the fixture wires the replicaset init script.
• BsonDiff reports diff on _id — default scrub list includes _id, _etag, _ts. If your domain exposes a domain-level Id alongside _id, scrub it too.

See .

Provider quirks + edge cases

• MongoDB's default write-concern is w: 1 (acknowledged by primary) — tests asserting durability across a restart must use w: "majority".
• Index creation is synchronous for small data, async for large. Test helpers assume small.
• Driver 3.x uses MongoClient which is thread-safe; do not wrap in using — dispose is process-level.

Benchmarks

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

Related docs

• Family base:

License

MIT. See .