JasperFx.Events.ComplianceTests

JasperFx.Events.ComplianceTests

Shared behavioral compliance test suites for Critter Stack event stores — the same event sourcing expectations asserted against Marten (PostgreSQL), Polecat (SQL Server), and any future store built on JasperFx.Events.

This package ships C# source, not a compiled assembly. That is forced, not a preference: JasperFx.Events.SourceGenerator emits aggregate dispatchers per consuming assembly and binds each product's own session type, so the shared aggregates have to be compiled inside each consumer. Compiling in the consumer also sidesteps package-version skew and LangVersion/ImplicitUsings differences between the repos.

Using it

Reference the package from a test project that already has xunit v3 and Shouldly, then supply three things.

1. Five global aliases naming your store's own types. The shared suites declare aggregates and projections at file scope, so they cannot reach the <TOperations, TQuerySession> pair the suite classes are generic over. The source generator resolves these by type name, so aliases are enough:

global using ComplianceQuerySession = Marten.IQuerySession;
global using ComplianceOperations = Marten.IDocumentOperations;
global using ComplianceEventProjection = Marten.Events.Projections.EventProjection;
global using ComplianceStringPartyProjectionBase =
    Marten.Events.Aggregation.SingleStreamProjection<
        JasperFx.Events.ComplianceTests.StringQuestParty, string>;
global using ComplianceMultiStreamProjectionBase =
    Marten.Events.Projections.MultiStreamProjection<
        JasperFx.Events.ComplianceTests.ComplianceDepartment, string>;

ComplianceQuerySession binds the EvolveAsync(IEvent, …) convention on the self-aggregating fixtures; the next two bind the EventProjection suites to your product's own projection base and writable session. The last two are closed generics, because the single stream and multi stream projection bases are generic over both the document and its identity — they bind the string-identity and multi-stream suites' custom projections to your product's SingleStreamProjection<TDoc, TId> and MultiStreamProjection<TDoc, TId>.

2. A concrete fixture closing EventStoreComplianceFixture<TOperations, TQuerySession> over your store's session pair. Everything portable in the suites runs through the shared JasperFx surfaces (IEventStoreOperations, IEventRegistry, IProjectionDaemon); the fixture only has to supply what no shared interface declares — store construction from a ComplianceStoreConfig, session acquisition, SaveChangesAsync, document load-back, batched DCB queries, and teardown.

3. Two partial classes, for the two suites whose shared type cannot be reached by an alias.

FlatTableProjectionCompliance is the first: every product's flat-table projection base takes constructor arguments describing where the table lives, and those signatures genuinely differ, so no single base(...) call satisfies all of them. Declaring the primary key column is per-product for the same reason — that API hangs off each dialect's own Table type. The library owns the table name, the projection name and every event mapping; a consumer supplies the rest:

namespace JasperFx.Events.ComplianceTests;

public partial class ComplianceFlatTableProjection : FlatTableProjection
{
    public ComplianceFlatTableProjection() : base(TableName, SchemaNameSource.DocumentSchema)
    {
        Table.AddColumn<Guid>("id").AsPrimaryKey();   // your dialect's column API
        ConfigureMappings();                          // everything portable
    }
}

If your base takes a literal schema name rather than resolving the store's, pass ComplianceFlatTableProjection.SchemaName — the suite configures its store with the same constant, and the two have to agree or the projection writes into a table the suite is not reading.

SubscriptionCompliance is the second, for a subtler reason. Both products declare ISubscription with an identical member — Task<IChangeListener> ProcessEventsAsync(EventRange, ISubscriptionController, IDocumentOperations, CancellationToken) — but IChangeListener is a per-product type, so the signature cannot be written once. The library owns the recording, the waiting and the subscription name; a consumer supplies only the interface implementation:

namespace JasperFx.Events.ComplianceTests;

public partial class ComplianceSubscription : ISubscription   // your product's ISubscription
{
    public Task<IChangeListener> ProcessEventsAsync(EventRange page, ISubscriptionController controller,
        IDocumentOperations operations, CancellationToken cancellationToken)
    {
        Record(page.Events);
        return Task.FromResult<IChangeListener>(NullChangeListener.Instance);
    }
}

Your registrar's Subscribe should pin the name to ComplianceSubscription.SubscriptionName; progression is keyed on it and the products disagree on what an unnamed subscription defaults to.

Then enroll each suite with an empty subclass:

public class dcb_tag_query_and_consistency_compliance
    : DcbTagQueryAndConsistencyCompliance<MyComplianceFixture, IDocumentOperations, IQuerySession>;

Capability gates

Where a store genuinely cannot support a behavior, override the virtual bool Supports... flags on the fixture; the affected tests skip rather than fail. Gates are meant to be temporary and tracked — a suite failing on your store is usually a product bug, not a test to soften.

Local dev loop

Both current consumers accept a ComplianceSourceDir property that swaps the published suites for a working copy, so a new wave can be validated against a real store before the JasperFx release:

dotnet test src/EventSourcingTests/EventSourcingTests.csproj -f net9.0 \
    -p:ComplianceSourceDir=/path/to/jasperfx/src/JasperFx.Events.ComplianceTests

What is in scope

The library asserts behavior that every JasperFx.Events store owes its users, reached through the shared interfaces (IEventStoreOperations, IQueryEventStore, IEventRegistry, IEventStore, IProjectionDaemon). Covered today:

The document contract (jasperfx#647)

A second, independent family covers the small document slice that JasperFx.Events now abstracts alongside the event store — JasperFx.Events.Documents:

Enrollment is deliberately much cheaper than the event side. DocumentStorageComplianceFixture has three abstract members — build a store, hand back an IDocumentSessionFactory, wipe the data — and is not generic over the store's session pair, because everything the document suites do runs through the shared contracts. That asymmetry is the result being demonstrated, not an inconsistency: if a document suite ever needs a fixture member that reaches past the interfaces, the contract has a hole and the contract is what should change.

public class my_document_fixture : DocumentStorageComplianceFixture
{
    protected override Task BuildStoreAsync(DocumentComplianceConfig config) { /* ... */ }
    public override IDocumentSessionFactory Sessions => _store;
    public override Task CleanDocumentDataAsync() { /* ... */ }
}

public class document_query_compliance : DocumentQueryCompliance<my_document_fixture>;

These suites are the one part of the library that is executed inside this repo as well as by its consumers: EventStoreTests enrolls an in-memory reference implementation, so the shared definition is known to be satisfiable before three products are held to it. That reference implementation is a test double, not a product — it exists to keep the suite honest.

Note that a consumer whose test project carries a global using Marten; (or the Polecat equivalent) will hit an ambiguity between that product's async LINQ terminators and JasperFx.Events.Documents.DocumentQueryableExtensions, which share names and receiver types. Scoping or removing the global using for the compliance compile resolves it.

What is deliberately out of scope

Storage layout and DDL, table partitioning, node distribution / HotCold, and high-water detection internals. If a behavior only makes sense in terms of one engine's storage, it belongs in that product's own test suite, not here.

General LINQ and query-provider behavior is out of scope permanently, not pending a contract. The stores' query languages diverge structurally enough that a shared suite would pin coincidence rather than contract. This has been the position since the library was designed; it is restated here because it had drifted into "blocked until a shared document store contract exists", which wrongly reads as deferred work. It is not deferred. A file like Polecat.Tests/Linq/additional_linq_operator_tests.cs is a product-owned test file, not a port awaiting absorption (marten#5155).

DocumentQueryCompliance is not a counter-example to that, and must not be allowed to grow into one. It pins a closed minimum translatable set — Where, Select, OrderBy / OrderByDescending, ThenBy / ThenByDescending, Take, Skip, Distinct — because a consumer holding only an IQueryable<T> has no way to discover whether a store translates those or silently does not. That set is closed by measurement (the operators CritterWatch.Services actually applies to a Query<T>() chain), not open by principle. Operators outside it stay product-owned however many stores happen to support them.

Session semantics are now in scope, via the document contract above. The rest of the document-db side — patching, bulk insert, LINQ joins / grouping / Include, soft-delete semantics, document metadata, session listeners, the stores' Advanced surfaces and schema management — stays out, and that exclusion is now a settled boundary rather than an open question: those are the surfaces jasperfx#647 deliberately declined to abstract.

New cross-store event sourcing behavior should land as a compliance suite first, and only then be enrolled by each product.