duraflows-tester

name	duraflows-tester
description	Provides testing patterns for duraflows workflows. Use when writing tests for WorkflowDefinition objects, WorkflowCommand handlers, workflow lifecycle, timeout processing, onEnter chains, or any code that imports from @duraflows/core, @duraflows/pg, or @duraflows/nestjs in test files.

duraflows Testing Guide

Testing patterns for duraflows workflows using Vitest. Covers clock injection, in-memory stores, command mocking, timeout simulation, and assertion patterns.

---

Test Framework

duraflows uses Vitest with global test APIs (describe, it, expect, vi).

import { describe, it, expect, beforeEach } from "vitest";

---

In-Memory Test Doubles

Use these in-memory implementations instead of PostgreSQL for unit and integration tests. Define them locally in your test file or in a shared test helper.

For adapter authors: if you're testing a custom WorkflowInstanceStore implementation (Prisma, Drizzle, TypeORM, Kysely, etc.), use the v1.0.0 conformance suite instead — see Adapter Conformance. It exercises the persistence contract more thoroughly than the doubles below.

InMemoryInstanceStore

import type { WorkflowInstanceStore, WorkflowInstance } from "@duraflows/core";

class InMemoryInstanceStore implements WorkflowInstanceStore {
  private readonly instances = new Map<string, WorkflowInstance>();

  async create(instance: WorkflowInstance): Promise<void> {
    this.instances.set(instance.uuid, structuredClone(instance));
  }

  async findByUuid(uuid: string): Promise<WorkflowInstance | null> {
    const inst = this.instances.get(uuid);
    return inst ? structuredClone(inst) : null;
  }

  async lockByUuid(uuid: string): Promise<WorkflowInstance | null> {
    return this.findByUuid(uuid); // no real locking needed in memory
  }

  async update(instance: WorkflowInstance): Promise<void> {
    this.instances.set(instance.uuid, structuredClone(instance));
  }

  async findExpired(limit: number, now: Date): Promise<WorkflowInstance[]> {
    const results: WorkflowInstance[] = [];
    for (const inst of this.instances.values()) {
      if (inst.expiresAt && inst.expiresAt <= now) {
        results.push(structuredClone(inst));
        if (results.length >= limit) break;
      }
    }
    return results;
  }
}

Important: Use structuredClone() in all methods to prevent shared references between test code and store.

InMemoryHistoryStore

import { randomUUID } from "node:crypto";
import type { WorkflowHistoryStore, WorkflowHistoryRecord } from "@duraflows/core";

class InMemoryHistoryStore implements WorkflowHistoryStore {
  private readonly records: Array<WorkflowHistoryRecord & { uuid: string }> = [];

  async append(entry: WorkflowHistoryRecord): Promise<string> {
    const uuid = randomUUID();
    this.records.push({ ...entry, uuid });
    return uuid;
  }

  async findByInstanceUuid(
    workflowInstanceUuid: string,
    options?: { limit?: number; offset?: number },
  ): Promise<WorkflowHistoryRecord[]> {
    const matching = this.records.filter((r) => r.workflowInstanceUuid === workflowInstanceUuid);
    const offset = options?.offset ?? 0;
    const limit = options?.limit ?? matching.length;
    return matching.slice(offset, offset + limit);
  }
}

InMemoryTransactionRunner

import type { WorkflowTransactionRunner } from "@duraflows/core";

class InMemoryTransactionRunner implements WorkflowTransactionRunner {
  async runInTransaction<T>(callback: () => Promise<T>): Promise<T> {
    return callback(); // simple pass-through
  }
}

---

Clock Injection

Always inject a fixed clock for deterministic tests.

Fixed Clock

import type { WorkflowClock } from "@duraflows/core";

const fixedDate = new Date("2025-06-15T12:00:00.000Z");
const clock: WorkflowClock = { now: () => fixedDate };

Advanceable Clock

let currentTime = new Date("2025-06-15T12:00:00.000Z");
const clock: WorkflowClock = { now: () => currentTime };

// Later in tests:
currentTime = new Date("2025-06-16T12:00:00.000Z"); // advance 24 hours

---

Runtime Setup for Tests

import {
  WorkflowRuntime,
  InMemoryDefinitionRegistry,
  InMemoryCommandRegistry,
  WorkflowValidator,
  WorkflowCompiler,
} from "@duraflows/core";

let runtime: WorkflowRuntime;
let instanceStore: InMemoryInstanceStore;
let historyStore: InMemoryHistoryStore;
let commandRegistry: InMemoryCommandRegistry;

beforeEach(() => {
  instanceStore = new InMemoryInstanceStore();
  historyStore = new InMemoryHistoryStore();

  const definitionRegistry = new InMemoryDefinitionRegistry({
    validator: new WorkflowValidator(),
    compiler: new WorkflowCompiler(),
  });
  definitionRegistry.register(myWorkflowDefinition);

  commandRegistry = new InMemoryCommandRegistry();
  // Register commands (see Command Mocking section)

  runtime = new WorkflowRuntime({
    definitionRegistry,
    commandRegistry,
    instanceStore,
    historyStore,
    transactionRunner: new InMemoryTransactionRunner(),
    clock: { now: () => new Date("2025-06-15T12:00:00.000Z") },
    // v1.1.0: only required if any registered definition uses an event guard.
    // Pass an `InMemoryGuardRegistry` (or any `WorkflowGuardRegistry`) here.
    // guardRegistry,
  });
});

---

Command Mocking

Helper Functions

import type { WorkflowCommand, CommandResult } from "@duraflows/core";

function successCommand(overrides: Partial<CommandResult> = {}): WorkflowCommand {
  return {
    execute: async () => ({ ok: true, ...overrides }),
  };
}

function failureCommand(overrides: Partial<CommandResult> = {}): WorkflowCommand {
  return {
    execute: async () => ({
      ok: false,
      code: "FAIL",
      message: "command failed",
      ...overrides,
    }),
  };
}

Context-Mutating Commands

const enrichCommand: WorkflowCommand = {
  execute: async (_subject, ctx) => {
    ctx.context.enriched = true;
    ctx.context.enrichedAt = ctx.now.toISOString();
    return { ok: true, code: "ENRICHED" };
  },
};

Best-Effort Commands (v1.0.0)

function bestEffortFailureCommand(): WorkflowCommand {
  return {
    bestEffort: true,
    execute: async () => ({ ok: false, code: "PROVIDER_DOWN" }),
  };
}

function bestEffortThrowCommand(): WorkflowCommand {
  return {
    bestEffort: true,
    execute: async () => {
      throw new Error("flaky vendor");
    },
  };
}

Commands Reading commandMetadata (v1.0.0)

const notifyCommand: WorkflowCommand = {
  execute: async (_subject, ctx) => {
    const channel = ctx.commandMetadata.channel as string;
    const template = ctx.commandMetadata.template as string;
    return {
      ok: true,
      code: "NOTIFIED",
      metadata: { channel, template, transitionUuid: ctx.transitionUuid },
    };
  },
};

Mock Registry Factory

function makeRegistry(commands: Record<string, WorkflowCommand>): WorkflowCommandRegistry {
  return {
    get(name: string) {
      const cmd = commands[name];
      if (!cmd) throw new Error(`Command "${name}" not found`);
      return cmd;
    },
    has(name: string) {
      return name in commands;
    },
  };
}

Mock Guards (v1.1.0)

A WorkflowGuard is a read-only predicate. Helpers parallel to the command helpers:

import type { WorkflowGuard } from "@duraflows/core";

function passingGuard(name = "pass"): WorkflowGuard {
  return { name, evaluate: () => true };
}

function rejectingGuard(name = "reject"): WorkflowGuard {
  return { name, evaluate: () => false };
}

// Read commandMetadata to drive the predicate from the workflow definition
function metadataGuard(name = "minTier"): WorkflowGuard {
  return {
    name,
    evaluate: (subject: { tier: string }, ctx) => {
      const required = ctx.commandMetadata.minTier as string;
      return tierAtLeast(subject.tier, required);
    },
  };
}

For test isolation, register guards into an InMemoryGuardRegistry:

import { InMemoryGuardRegistry } from "@duraflows/core";

const guardRegistry = new InMemoryGuardRegistry();
guardRegistry.register("isVerified", passingGuard("isVerified"));

The guard's name property is informational — the runtime resolves the registry by eventDef.guard.name (the ref name in the definition) and reports that ref name in result.rejectedBy. Tests asserting on rejectedBy should match the ref name, not the implementation's name.

Registration

commandRegistry.register("validateOrder", successCommand());
commandRegistry.register("chargePayment", failureCommand({ code: "INSUFFICIENT_FUNDS" }));
commandRegistry.register("enrichData", enrichCommand);

---

Testing Patterns

Full Lifecycle Test

it("completes a workflow from creation to terminal state", async () => {
  const instance = await runtime.createInstance({
    workflowName: "order",
    metadata: { orderId: "ORD-001" },
  });
  expect(instance.currentState).toBe("new");

  const result = await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "PaymentReceived",
    subject: { amount: 100 },
    triggerMetadata: { source: "test" },
  });

  expect(result.outcome).toBe("success");
  expect(result.fromState).toBe("new");
  expect(result.toState).toBe("exportable");
});

Testing with WorkflowHandle

it("uses handle for sequential operations", async () => {
  const instance = await runtime.createInstance({ workflowName: "order" });
  const handle = runtime.getHandle(instance.uuid);

  await handle.triggerEvent("PaymentReceived");

  const current = await handle.getInstance();
  expect(current?.currentState).toBe("exportable");

  const events = await handle.getAvailableEvents();
  expect(events.map((e) => e.eventName)).toContain("Export");
});

Testing Command Failures with errorState

it("transitions to errorState when command fails", async () => {
  commandRegistry.register("chargePayment", failureCommand({ code: "DECLINED" }));

  const result = await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "ChargePayment",
  });

  expect(result.outcome).toBe("failure");
  expect(result.toState).toBe("payment_failed");
});

Testing bestEffort Commands (v1.0.0)

A bestEffort: true command's failure must NOT taint outcome or stop the chain. Pin this behavior:

it("bestEffort returned ok:false does not taint outcome", async () => {
  commandRegistry.register("notify", bestEffortFailureCommand());
  commandRegistry.register("settle", successCommand({ code: "SETTLED" }));
  // Workflow event runs commands in order: [notify (bestEffort), settle]

  const result = await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Finalize",
  });

  expect(result.outcome).toBe("success"); // bestEffort failure ignored
  expect(result.toState).toBe("finalized");
  expect(result.commandResults[0].ok).toBe(false); // notify failure recorded
  expect(result.commandResults[1].ok).toBe(true); // settle still ran
});

it("bestEffort thrown error is captured as BEST_EFFORT_THROWN", async () => {
  commandRegistry.register("notify", bestEffortThrowCommand());

  const result = await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Finalize",
  });

  expect(result.outcome).toBe("success");
  const notifyResult = result.commandResults[0];
  expect(notifyResult.ok).toBe(false);
  expect(notifyResult.code).toBe("BEST_EFFORT_THROWN");
  // The error field is a serializable shape — safe for JSON persistence
  expect(notifyResult.error).toMatchObject({
    name: "Error",
    message: "flaky vendor",
  });
});

Testing Command Failures without errorState

import { CommandFailureError } from "@duraflows/core";

it("throws CommandFailureError when no errorState defined", async () => {
  commandRegistry.register("riskyAction", failureCommand());

  await expect(
    runtime.triggerEvent({
      workflowInstanceUuid: instance.uuid,
      eventName: "DoRiskyThing",
    }),
  ).rejects.toThrow(CommandFailureError);
});

Testing Invalid Events

import { InvalidEventError } from "@duraflows/core";

it("throws InvalidEventError for unavailable event", async () => {
  // Instance is in "new" state, "Ship" is not available there
  await expect(
    runtime.triggerEvent({
      workflowInstanceUuid: instance.uuid,
      eventName: "Ship",
    }),
  ).rejects.toThrow(InvalidEventError);
});

Testing Context Mutations

it("commands can write to context", async () => {
  commandRegistry.register("enrich", {
    execute: async (_subject, ctx) => {
      ctx.context.processed = true;
      ctx.context.processedAt = ctx.now.toISOString();
      return { ok: true };
    },
  });

  await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Process",
  });

  const updated = await instanceStore.findByUuid(instance.uuid);
  expect(updated?.context.processed).toBe(true);
  expect(updated?.context.processedAt).toBe("2025-06-15T12:00:00.000Z");
});

Testing Context Merge Order

it("state context wins over command writes for same key", async () => {
  // Command writes status = "processing"
  commandRegistry.register("process", {
    execute: async (_subject, ctx) => {
      ctx.context.status = "processing";
      return { ok: true };
    },
  });

  // But target state defines status: "completed"
  // State context merges on top -> final value is "completed"
  await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Process",
  });

  const updated = await instanceStore.findByUuid(instance.uuid);
  expect(updated?.context.status).toBe("completed");
});

Testing Metadata Immutability

it("metadata is frozen during command execution", async () => {
  commandRegistry.register("check", {
    execute: async (_subject, ctx) => {
      expect(Object.isFrozen(ctx.metadata)).toBe(true);
      expect(() => {
        (ctx.metadata as Record<string, unknown>).injected = "value";
      }).toThrow();
      return { ok: true };
    },
  });

  await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Check",
  });
});

---

Testing Timeouts

Use an advanceable clock to simulate time passing. The runtime sets expiresAt automatically when an instance enters a state with a timeout event, using the injected clock. Advance the clock past that point, then call processExpiredWorkflows().

Advanceable Clock Pattern (Recommended)

it("processes expired workflows after timeout elapses", async () => {
  // 1. Set up runtime with advanceable clock
  let currentTime = new Date("2025-06-15T12:00:00.000Z");
  const clock = { now: () => currentTime };
  const runtime = new WorkflowRuntime({
    definitionRegistry,
    commandRegistry,
    instanceStore,
    historyStore,
    transactionRunner: new InMemoryTransactionRunner(),
    clock,
  });

  // 2. Create instance — enters a state with a 2-hour timeout
  const instance = await runtime.createInstance({ workflowName: "order" });
  // Runtime automatically sets expiresAt = clock.now() + 2 hours

  // 3. Advance clock past the timeout
  currentTime = new Date("2025-06-15T14:01:00.000Z"); // 2h 1m later

  // 4. Process expired workflows — clock.now() is used for the comparison
  const result = await runtime.processExpiredWorkflows();
  expect(result.processed).toBe(1);
  expect(result.failed).toHaveLength(0);

  // 5. Verify state transition
  const updated = await instanceStore.findByUuid(instance.uuid);
  expect(updated?.currentState).toBe("escalated"); // timeout target state
});

Verifying Timeout Trigger Metadata

it("timeout events have source: timeout in triggerMetadata", async () => {
  // ... setup and process expired ...

  const history = await historyStore.findByInstanceUuid(instance.uuid);
  const timeoutRecord = history.find((h) => h.eventName === "AutoClose");
  expect(timeoutRecord?.triggerMetadata?.source).toBe("timeout");
});

---

Testing onEnter Chains

Single onEnter Hop

it("auto-transitions via onEnter", async () => {
  // Triggering "Submit" transitions to "validating" which has onEnter -> "validated"
  const result = await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Submit",
  });

  // Returns the FINAL state, not the intermediate
  expect(result.toState).toBe("validated");
});

Verifying onEnter History Records

it("records onEnter hops in history", async () => {
  await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Submit",
  });

  const history = await historyStore.findByInstanceUuid(instance.uuid);
  expect(history).toHaveLength(2);

  // First record: the triggered event
  expect(history[0].eventName).toBe("Submit");
  expect(history[0].toState).toBe("validating");

  // Second record: the onEnter auto-transition
  expect(history[1].eventName).toBe("onEnter");
  expect(history[1].toState).toBe("validated");
  expect(history[1].triggerMetadata?.source).toBe("onEnter");
});

Asserting OnEnter Chain outcome (v1.0.0)

OnEnterChainResult.outcome aggregates across hops: it is "failure" if any hop routed to errorState, otherwise "success". Prefer asserting on outcome over inspecting the last hop or last command result. The aggregate is also surfaced on the WorkflowExecutionResult.outcome returned from triggerEvent:

it("aggregates outcome across event + onEnter chain", async () => {
  // Event succeeds, but onEnter hop routes to errorState — outcome must be "failure"
  const result = await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Submit",
  });
  expect(result.outcome).toBe("failure");
  expect(result.toState).toBe("validation_failed");
});

Testing onEnter Depth Limit

import { OnEnterDepthExceededError } from "@duraflows/core";

it("throws OnEnterDepthExceededError when chain is too deep", async () => {
  const limitedRuntime = new WorkflowRuntime({
    // ... same setup but:
    maxOnEnterDepth: 2,
  });

  // Workflow with 3+ onEnter hops will exceed limit
  await expect(
    limitedRuntime.triggerEvent({
      workflowInstanceUuid: instance.uuid,
      eventName: "Start",
    }),
  ).rejects.toThrow(OnEnterDepthExceededError);
});

---

Testing Observers (v1.0.0)

Observers fire post-commit, at-most-once, sequentially, error-contained. Test them with a recording-observer fixture that captures every StateEnterEvent.

Recording Observer

import type { WorkflowObserver, StateEnterEvent } from "@duraflows/core";

function recordingObserver(name = "test"): WorkflowObserver & { events: StateEnterEvent[] } {
  const events: StateEnterEvent[] = [];
  return {
    name,
    events,
    onEnter: (event) => {
      events.push(event);
    },
  };
}

Pass it via WorkflowRuntimeOptions.observers:

const observer = recordingObserver();
runtime = new WorkflowRuntime({
  /* ... */
  observers: [observer],
});

Observer Fires on Every State Entry

it("fires observer on createInstance and triggerEvent", async () => {
  const observer = recordingObserver();
  // ... wire observer into runtime ...

  const instance = await runtime.createInstance({ workflowName: "order" });
  await runtime.triggerEvent({ workflowInstanceUuid: instance.uuid, eventName: "Submit" });

  expect(observer.events).toHaveLength(2);
  expect(observer.events[0]).toMatchObject({
    fromState: null, // initial entry
    toState: "new",
    triggerEvent: null,
  });
  expect(observer.events[1]).toMatchObject({
    fromState: "new",
    toState: "submitted",
    triggerEvent: "Submit",
  });
});

Observer transitionUuid Matches Command Context

This is the v1.0.0 correlation guarantee: the transitionUuid an observer sees on event.transitionUuid is the same UUID the commands that ran on entry to that state saw on ctx.transitionUuid.

it("transitionUuid correlates command context with observer event", async () => {
  let commandTransitionUuid: string | undefined;
  commandRegistry.register("recordUuid", {
    execute: async (_subject, ctx) => {
      commandTransitionUuid = ctx.transitionUuid;
      return { ok: true };
    },
  });

  const observer = recordingObserver();
  // ... wire observer into runtime ...

  await runtime.triggerEvent({ workflowInstanceUuid: instance.uuid, eventName: "Submit" });

  const matchingEvent = observer.events.find((e) => e.toState === "submitted");
  expect(matchingEvent?.transitionUuid).toBe(commandTransitionUuid);
});

Observer Errors Don't Affect the Workflow

import type { ObserverErrorHandler } from "@duraflows/core";

it("observer throw is contained and routed to onObserverError", async () => {
  const errors: Array<{ name: string; message: string }> = [];
  const onObserverError: ObserverErrorHandler = (error, observer) => {
    errors.push({
      name: observer.name,
      message: error instanceof Error ? error.message : String(error),
    });
  };

  const throwingObserver: WorkflowObserver = {
    name: "throws",
    onEnter: () => {
      throw new Error("boom");
    },
  };

  runtime = new WorkflowRuntime({
    /* ... */
    observers: [throwingObserver],
    onObserverError,
  });

  // Workflow still completes successfully
  const result = await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Submit",
  });
  expect(result.outcome).toBe("success");

  // Observer error was captured, not propagated
  expect(errors).toEqual([{ name: "throws", message: "boom" }]);
});

Observers and Command-Only Events

A command-only event (no targetState) DOES fire the observer — as a self-transition with fromState === toState. Test for this if your observer behavior depends on it:

it("command-only events fire observer with fromState === toState", async () => {
  // Workflow has a `note_added` event in `pending` with no targetState
  await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "note_added",
    subject: { note: "test" },
  });

  const last = observer.events[observer.events.length - 1];
  expect(last.fromState).toBe("pending");
  expect(last.toState).toBe("pending");
  expect(last.triggerEvent).toBe("note_added");
});

---

Testing Guards (v1.1.0)

A guard is a read-only predicate that runs before any commands. If it returns false, the event short-circuits with outcome: "guard-rejected", no commands run, no state change. The patterns below cover the contract: pass-through, rejection short-circuit, history row, the errorState boundary, purity, and ref-name-vs-implementation-name divergence — plus timeout interaction and bootstrap validation.

1. Pass-through: guard returns true, commands run, state changes

it("passes through when guard returns true", async () => {
  guardRegistry.register("isVerified", passingGuard("isVerified"));
  commandRegistry.register("createOrder", successCommand({ code: "CREATED" }));

  const result = await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Submit", // event has guard: { name: "isVerified" }
  });

  expect(result.outcome).toBe("success");
  expect(result.toState).toBe("submitted");
  expect(result.rejectedBy).toBeUndefined();
  expect(result.commandResults).toHaveLength(1);
});

2. Rejection short-circuit: no commands, no state change, rejectedBy set

it("short-circuits when guard returns false", async () => {
  guardRegistry.register("isVerified", rejectingGuard("isVerified"));
  // Mark createOrder so we can assert it never ran
  let executed = false;
  commandRegistry.register("createOrder", {
    execute: async () => {
      executed = true;
      return { ok: true };
    },
  });

  const result = await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Submit",
  });

  expect(result.outcome).toBe("guard-rejected");
  expect(result.fromState).toBe("draft");
  expect(result.toState).toBe("draft"); // unchanged
  expect(result.rejectedBy).toBe("isVerified"); // declared eventDef.guard.name
  expect(result.commandResults).toEqual([]);
  expect(executed).toBe(false);
});

3. History row records the rejection

it("appends a history row with outcome guard-rejected", async () => {
  guardRegistry.register("isVerified", rejectingGuard());

  await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Submit",
  });

  const history = await historyStore.findByInstanceUuid(instance.uuid);
  // findByInstanceUuid is contracted to return newest-first (created_at DESC),
  // so the most recent row is at index 0.
  const latest = history[0];
  expect(latest).toMatchObject({
    eventName: "Submit",
    fromState: "draft",
    toState: "draft",
    outcome: "guard-rejected",
    rejectedBy: "isVerified", // ref name from the definition
    commandResultsJson: [], // WorkflowHistoryRecord field name is commandResultsJson
  });
});

4. errorState does NOT catch guard rejections

This is the boundary that distinguishes a guard from a routing errorState. Even when the event has both, a guard rejection bypasses errorState:

it("guard rejection is not routed to errorState", async () => {
  // Event has guard: { name: "isVerified" }, errorState: "rejected"
  guardRegistry.register("isVerified", rejectingGuard());

  const result = await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Submit",
  });

  expect(result.outcome).toBe("guard-rejected");
  expect(result.toState).not.toBe("rejected"); // stays in current state
});

5. Guard purity: ctx.context is deep-frozen

The runtime hands the guard a deep-cloned, deep-frozen view of ctx.context. Mutations throw under strict mode rather than silently leaking. Pin this so a future refactor can't break the contract:

it("guard cannot mutate ctx.context", async () => {
  let mutationError: unknown;
  guardRegistry.register("frozenCheck", {
    name: "frozenCheck",
    evaluate: (_subject, ctx) => {
      try {
        (ctx.context as Record<string, unknown>).injected = "leak";
      } catch (err) {
        mutationError = err;
      }
      return true; // pass through so we can inspect mutationError
    },
  });

  await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "CheckPurity",
  });

  expect(mutationError).toBeInstanceOf(TypeError); // strict-mode write to frozen object
  const updated = await instanceStore.findByUuid(instance.uuid);
  expect(updated?.context.injected).toBeUndefined();
});

6. Guard ref-name vs implementation-name divergence

Custom registries can alias — the registered guard's .name and the eventDef.guard.name ref can diverge. The runtime always reports the ref name:

it("rejectedBy reports the ref name, not the implementation name", async () => {
  // Definition: events.Submit.guard = { name: "isCustomerVerified" }
  guardRegistry.register("isCustomerVerified", {
    name: "internal-guard-impl-v2", // unrelated
    evaluate: () => false,
  });

  const result = await runtime.triggerEvent({
    workflowInstanceUuid: instance.uuid,
    eventName: "Submit",
  });

  expect(result.rejectedBy).toBe("isCustomerVerified"); // ref name wins
});

Timeout-Driven Guard Rejection

When a timeout-triggered event has a guard that rejects, the runtime additionally clears expiresAt so the next sweep won't re-pick the same instance, and counts the rejection toward result.rejected (not processed):

it("timeout sweep counts rejected separately from processed", async () => {
  guardRegistry.register("readyToAutoProgress", rejectingGuard());

  // ... create instance, advance clock past timeout deadline ...

  const result = await runtime.processExpiredWorkflows();
  expect(result.processed).toBe(0);
  expect(result.rejected).toBe(1); // v1.1.0
  expect(result.failed).toEqual([]);

  const updated = await instanceStore.findByUuid(instance.uuid);
  expect(updated?.expiresAt).toBeNull(); // cleared so next sweep skips this row
  expect(updated?.currentState).toBe(/* unchanged */);
});

Bootstrap Validation: knownGuardNames

When using the array-based guards option (or registering into InMemoryGuardRegistry and passing the resulting names), supply knownGuardNames to the validator so unresolved eventDef.guard.name refs fail at registration. With a custom registry, validation skips that check (the registry can't be enumerated) and unresolved refs surface at first use as WorkflowError:

import { WorkflowDefinitionError, WorkflowError } from "@duraflows/core";

it("validator rejects unknown guard refs when knownGuardNames is provided", () => {
  const registry = new InMemoryDefinitionRegistry({
    validator: new WorkflowValidator({
      knownGuardNames: new Set(["isVerified"]),
    }),
    compiler: new WorkflowCompiler(),
  });

  expect(() => registry.register(workflowReferencingMissingGuard)).toThrow(WorkflowDefinitionError);
});

it("custom registry: unresolved guard surfaces at first use", async () => {
  // No knownGuardNames passed — registration succeeds
  // Empty guard registry (no "isVerified" registered)
  await expect(
    runtime.triggerEvent({
      workflowInstanceUuid: instance.uuid,
      eventName: "Submit",
    }),
  ).rejects.toThrow(WorkflowError);
});

---

Adapter Conformance (v1.0.0)

For custom WorkflowInstanceStore implementations (Prisma, Drizzle, TypeORM, Kysely, etc.), use the shared conformance suite from @duraflows/core/testing:

import { describe } from "vitest";
import { runInstanceStoreConformance } from "@duraflows/core/testing";
import { MyInstanceStore } from "../src/my-instance-store.js";
import { MyTransactionRunner } from "../src/my-transaction-runner.js";

describe("MyInstanceStore (conformance)", () => {
  runInstanceStoreConformance({
    setup: async () => {
      // Construct your store + transaction runner against a real (or in-memory) database
      const store = new MyInstanceStore(db);
      const transactionRunner = new MyTransactionRunner(db);
      return {
        store,
        transactionRunner,
        teardown: async () => {
          await db.destroy();
        },
      };
    },
  });
});

The suite verifies:

• lockByUuid acquires a row-level lock and throws if called outside a transaction
• update enforces optimistic concurrency on version and throws WorkflowError on mismatch
• update does NOT modify metadata (write-once after create)
• findExpired honors limit + ordering and skips already-locked rows
• Nested-transaction reuse via transactionRunner.runInTransaction

A passing run is the contract guarantee that your adapter works with the runtime. @duraflows/pg and @duraflows/kysely both run it in CI.

---

Testing NestJS Integration

Module Compilation

import { Test, TestingModule } from "@nestjs/testing";
import { WorkflowModule, WorkflowService } from "@duraflows/nestjs";

describe("WorkflowModule", () => {
  let moduleRef: TestingModule;

  beforeEach(async () => {
    moduleRef = await Test.createTestingModule({
      imports: [
        WorkflowModule.forRoot({
          workflows: [myWorkflow],
          persistence: {
            instanceStore: new InMemoryInstanceStore(),
            historyStore: new InMemoryHistoryStore(),
            transactionRunner: new InMemoryTransactionRunner(),
          },
        }),
      ],
    }).compile();
  });

  it("provides WorkflowService", () => {
    const service = moduleRef.get(WorkflowService);
    expect(service).toBeDefined();
  });
});

---

Testing PostgreSQL Stores (Unit)

Mock the pg Pool and PoolClient:

import { vi } from "vitest";

function createMockPool(queryResult = { rows: [] }) {
  return { query: vi.fn().mockResolvedValue(queryResult) } as unknown as Pool;
}

it("inserts instance with correct SQL", async () => {
  const pool = createMockPool();
  const store = new PgWorkflowInstanceStore(pool);

  await store.create(sampleInstance);

  const [sql, params] = (pool.query as ReturnType<typeof vi.fn>).mock.calls[0];
  expect(sql).toContain("INSERT INTO workflow_instances");
  expect(params[0]).toBe(sampleInstance.uuid);
});

---

History Assertion Patterns

const history = await historyStore.findByInstanceUuid(instance.uuid);

// Assert record count
expect(history).toHaveLength(3);

// Assert individual record
expect(history[0]).toMatchObject({
  fromState: "new",
  eventName: "PaymentReceived",
  toState: "exportable",
  outcome: "success",
});

// Assert command results within a record
expect(history[0].commandResults).toHaveLength(2);
expect(history[0].commandResults[0].ok).toBe(true);
expect(history[0].commandResults[0].code).toBe("CHARGED");

// Assert trigger metadata
expect(history[0].triggerMetadata?.actor).toBe("user-123");

// v1.1.0 — guard-rejected row.
// findByInstanceUuid returns rows newest-first (created_at DESC), so the
// most recent row is at history[0]; locate the guard-rejected one explicitly
// instead of guessing an index.
const rejected = history.find((r) => r.outcome === "guard-rejected");
expect(rejected).toMatchObject({
  outcome: "guard-rejected",
  rejectedBy: "isVerified", // ref name; null becomes undefined when read back from PG
  fromState: "draft",
  toState: "draft",
  commandResultsJson: [], // WorkflowHistoryRecord field name (the runtime result uses commandResults)
});