Initial Commit

packages/api-stack/api/api-openapi-ui-scalar/src/instruments/instruments.test.ts

@@ -0,0 +1,74 @@
+import type { Counter, Meter, MeterProvider } from "@opentelemetry/api";
+import { describe, expect, it } from "@suaveplan/testing/runner";
+import {
+    createScalarInstruments,
+    recordUiRequest,
+    UI_LABEL_VALUE,
+} from "./instruments.js";
+
+interface RecordedObservation {
+    readonly value: number;
+    readonly attributes: Record<string, unknown>;
+}
+
+function buildRecordingProvider(): {
+    readonly provider: MeterProvider;
+    readonly observations: RecordedObservation[];
+} {
+    const observations: RecordedObservation[] = [];
+    const counter = {
+        add(value: number, attributes?: Record<string, unknown>): void {
+            observations.push({
+                value,
+                attributes: { ...(attributes ?? {}) },
+            });
+        },
+    } as unknown as Counter;
+    const meter = {
+        createCounter(): Counter {
+            return counter;
+        },
+    } as unknown as Meter;
+    const provider = {
+        getMeter(): Meter {
+            return meter;
+        },
+    } as unknown as MeterProvider;
+    return { provider, observations };
+}
+
+describe("instruments", () => {
+    it("createScalarInstruments wires a counter on the supplied provider", {
+        timeout: 5000,
+    }, () => {
+        const { provider, observations } = buildRecordingProvider();
+        const instruments = createScalarInstruments({
+            meterProvider: provider,
+        });
+        recordUiRequest(instruments);
+        expect(observations.length).toBe(1);
+        expect(observations[0]?.attributes).toEqual({ ui: UI_LABEL_VALUE });
+    });
+
+    it("recordUiRequest labels per-plugin observations", {
+        timeout: 5000,
+    }, () => {
+        const { provider, observations } = buildRecordingProvider();
+        const instruments = createScalarInstruments({
+            meterProvider: provider,
+        });
+        recordUiRequest(instruments, { plugin: "billing" });
+        expect(observations[0]?.attributes).toEqual({
+            ui: UI_LABEL_VALUE,
+            plugin: "billing",
+        });
+    });
+
+    it("falls back to the OTel global meter provider", {
+        timeout: 5000,
+    }, () => {
+        const instruments = createScalarInstruments();
+        expect(instruments.requestsTotal).toBeDefined();
+        expect(instruments.meter).toBeDefined();
+    });
+});