test: added regression tests for exporter selection based on protocol

Author: thomasbonenfant

tests/otel.test.ts

@@ -1,5 +1,31 @@
 import { describe, test, expect, afterEach } from "bun:test"
-import { buildResource } from "../src/otel.ts"
+import { OTLPLogExporter as OTLPHttpLogExporter } from "@opentelemetry/exporter-logs-otlp-http"
+import { OTLPLogExporter as OTLPProtoLogExporter } from "@opentelemetry/exporter-logs-otlp-proto"
+import { OTLPMetricExporter as OTLPHttpMetricExporter } from "@opentelemetry/exporter-metrics-otlp-http"
+import { OTLPMetricExporter as OTLPProtoMetricExporter } from "@opentelemetry/exporter-metrics-otlp-proto"
+import { OTLPTraceExporter as OTLPHttpTraceExporter } from "@opentelemetry/exporter-trace-otlp-http"
+import { OTLPTraceExporter as OTLPProtoTraceExporter } from "@opentelemetry/exporter-trace-otlp-proto"
+import { buildResource, setupOtel, type OtelProviders } from "../src/otel.ts"
+
+let providers: OtelProviders | undefined
+
+function exportersOf(currentProviders: OtelProviders) {
+  const meterProvider = currentProviders.meterProvider as unknown as {
+    _sharedState: { metricCollectors: Array<{ _metricReader: { _exporter: unknown } }> }
+  }
+  const loggerProvider = currentProviders.loggerProvider as unknown as {
+    _sharedState: { activeProcessor: { processors: Array<{ _exporter: unknown }> } }
+  }
+  const tracerProvider = currentProviders.tracerProvider as unknown as {
+    _activeSpanProcessor: { _spanProcessors: Array<{ _exporter: unknown }> }
+  }
+
+  return {
+    metric: meterProvider._sharedState.metricCollectors[0]!._metricReader._exporter,
+    log: loggerProvider._sharedState.activeProcessor.processors[0]!._exporter,
+    trace: tracerProvider._activeSpanProcessor._spanProcessors[0]!._exporter,
+  }
+}
 
 describe("buildResource", () => {
   const originalEnv = process.env["OTEL_RESOURCE_ATTRIBUTES"]
@@ -41,3 +67,30 @@ describe("buildResource", () => {
     expect(resource.attributes["service.name"]).toBe("my-override")
   })
 })
+
+describe("setupOtel", () => {
+  afterEach(async () => {
+    await providers?.tracerProvider.shutdown()
+    await providers?.loggerProvider.shutdown()
+    await providers?.meterProvider.shutdown()
+    providers = undefined
+  })
+
+  test("uses protobuf HTTP exporters for http/protobuf", async () => {
+    providers = await setupOtel("http://collector:4318", "http/protobuf", 60000, 5000, "1.2.3")
+    const exporters = exportersOf(providers)
+
+    expect(exporters.metric).toBeInstanceOf(OTLPProtoMetricExporter)
+    expect(exporters.log).toBeInstanceOf(OTLPProtoLogExporter)
+    expect(exporters.trace).toBeInstanceOf(OTLPProtoTraceExporter)
+  })
+
+  test("uses JSON HTTP exporters for http/json", async () => {
+    providers = await setupOtel("http://collector:4318", "http/json", 60000, 5000, "1.2.3")
+    const exporters = exportersOf(providers)
+
+    expect(exporters.metric).toBeInstanceOf(OTLPHttpMetricExporter)
+    expect(exporters.log).toBeInstanceOf(OTLPHttpLogExporter)
+    expect(exporters.trace).toBeInstanceOf(OTLPHttpTraceExporter)
+  })
+})