konnosDashboard
metrics-endpoint.test.ts54 lines · main
1import { beforeEach, describe, expect, test } from 'bun:test';
2
3import {
4 incCounter,
5 observeHistogram,
6 registerPoolGauges,
7 renderPrometheus,
8 resetMetrics,
9} from '../src/metrics.js';
10
11describe('metrics', () => {
12 beforeEach(() => {
13 resetMetrics();
14 });
15
16 test('renders counters in Prometheus format', () => {
17 incCounter('test_counter', { label: 'a' });
18 incCounter('test_counter', { label: 'a' });
19 incCounter('test_counter', { label: 'b' });
20 const out = renderPrometheus();
21 expect(out).toContain('test_counter{label="a"} 2');
22 expect(out).toContain('test_counter{label="b"} 1');
23 expect(out).toContain('# TYPE test_counter counter');
24 });
25
26 test('renders histogram with buckets', () => {
27 observeHistogram('test_histogram', 5);
28 observeHistogram('test_histogram', 25);
29 observeHistogram('test_histogram', 150);
30 const out = renderPrometheus();
31 expect(out).toContain('test_histogram_bucket{le="10"} 1');
32 expect(out).toContain('test_histogram_bucket{le="50"} 2');
33 expect(out).toContain('test_histogram_bucket{le="200"} 3');
34 expect(out).toContain('test_histogram_bucket{le="+Inf"} 3');
35 expect(out).toMatch(/test_histogram_count\s+3/);
36 expect(out).toMatch(/test_histogram_sum\s+180/);
37 expect(out).toContain('# TYPE test_histogram histogram');
38 });
39
40 test('exposes pool gauges from the registered provider', () => {
41 const fakePool = {
42 describeForMetrics: () => ({
43 isolatesByState: { ready: 2, in_flight: 1, spawning: 0, retiring: 0, dead: 0 },
44 poolSize: 3,
45 }),
46 };
47 registerPoolGauges(fakePool);
48 const out = renderPrometheus();
49 expect(out).toContain('# TYPE briven_runtime_pool_size gauge');
50 expect(out).toContain('briven_runtime_pool_size 3');
51 expect(out).toContain('briven_runtime_isolates_by_state{state="ready"} 2');
52 expect(out).toContain('briven_runtime_isolates_by_state{state="in_flight"} 1');
53 });
54});