test: impact metrics collection e2e (#10162)

src/lib/features/metrics/impact/impact-metrics.e2e.test.ts

@@ -0,0 +1,69 @@
+import {
+    type IUnleashTest,
+    setupAppWithCustomConfig,
+} from '../../../../test/e2e/helpers/test-helper.js';
+import dbInit, {
+    type ITestDb,
+} from '../../../../test/e2e/helpers/database-init.js';
+import getLogger from '../../../../test/fixtures/no-logger.js';
+import { MetricsTranslator } from './metrics-translator.js';
+import { impactRegister } from './impact-register.js';
+
+let app: IUnleashTest;
+let db: ITestDb;
+
+beforeAll(async () => {
+    db = await dbInit('impact_metrics', getLogger);
+    app = await setupAppWithCustomConfig(db.stores, {
+        experimental: {
+            flags: {
+                impactMetrics: true,
+            },
+        },
+    });
+});
+
+afterAll(async () => {
+    await app.destroy();
+    await db.destroy();
+});
+
+test('should store impact metrics in memory and be able to retrieve them', async () => {
+    // TODO: replace with POST metrics when it's ready
+    const metricsTranslator = new MetricsTranslator(impactRegister);
+
+    metricsTranslator.translateMetric({
+        name: 'labeled_counter',
+        help: 'with labels',
+        type: 'counter' as const,
+        samples: [
+            {
+                labels: { foo: 'bar' },
+                value: 5,
+            },
+        ],
+    });
+
+    metricsTranslator.translateMetric({
+        name: 'labeled_counter',
+        help: 'with labels',
+        type: 'counter' as const,
+        samples: [
+            {
+                labels: { foo: 'bar' },
+                value: 10,
+            },
+        ],
+    });
+
+    const response = await app.request
+        .get('/internal-backstage/impact/metrics')
+        .expect('Content-Type', /text/)
+        .expect(200);
+
+    const metricsText = response.text;
+
+    expect(metricsText).toContain('# HELP labeled_counter with labels');
+    expect(metricsText).toContain('# TYPE labeled_counter counter');
+    expect(metricsText).toMatch(/labeled_counter{foo="bar"} 15/);
+});