Testing

Import test doubles from the dedicated entrypoint:

import { configureMetrics, measure } from '@haskou/metrics';
import {
  InMemoryLoggerAdapter,
  InMemoryMetricsAdapter,
  ManualClock,
  ManualResourceUsageAdapter,
} from '@haskou/metrics/testing';

const adapter = new InMemoryMetricsAdapter();
const clock = new ManualClock();
const logger = new InMemoryLoggerAdapter();
const resources = new ManualResourceUsageAdapter();
const restore = configureMetrics({
  adapter,
  clock,
  logger,
  resourceUsage: resources,
});

measure('users.create', () => {
  clock.advance(8);
  return user;
});

expect(adapter.increments).toContainEqual(
  expect.objectContaining({
    name: 'users.create.calls',
    value: 1,
    attributes: {},
  }),
);
expect(adapter.observations[0]?.value).toBe(8);

restore();

InMemoryMetricsAdapter records counters and observations. InMemoryLoggerAdapter records serialized log entries. ManualClock controls elapsed time, while ManualResourceUsageAdapter controls CPU and memory snapshots. No-op metrics, logger, and resource adapters are also available from this testing entrypoint.

Included doubles

Double	Control and observations
InMemoryMetricsAdapter	increments, observations, and clear()
InMemoryLoggerAdapter	entries and clear()
ManualClock	Initial milliseconds, advance(), and set()
ManualResourceUsageAdapter	Initial resource values and set()
NoopMetricsAdapter	Discards metric measurements
NoopLoggerAdapter	Discards structured logs
NoopResourceUsageAdapter	Returns an empty resource snapshot

RecordedIncrement and RecordedObservation are aliases of MetricMeasurementPrimitives, so tests can assert kind, unit, operation, name, value, and attributes without using a vendor SDK.