test(instrumentation/express): cover

Author: Peter Marton

Diff for: package-lock.json

@@ -51,7 +51,8 @@
     "request": "2.81.0",
     "request-promise-native": "1.0.4",
     "sinon": "2.3.6",
-    "sinon-chai": "2.11.0"
+    "sinon-chai": "2.11.0",
+    "super-request": "1.2.0"
   },
   "engines": {
     "node": ">=8.0.0"

Diff for: package.json

@@ -78,6 +78,7 @@ function unpatch (express) {
 module.exports = {
   module: 'express',
   supportedVersions: ['4.x'],
+  TAG_REQUEST_PATH,
   OPERATION_NAME,
   patch,
   unpatch

Diff for: src/instrumentation/express.js

@@ -0,0 +1,87 @@
+'use strict'
+
+const request = require('super-request')
+const { expect } = require('chai')
+const { Tracer, Tags } = require('opentracing')
+const express = require('express')
+const cls = require('../cls')
+const instrumentation = require('./express')
+
+describe('instrumentation: express', () => {
+  let tracer
+  let mockSpan
+
+  beforeEach(function () {
+    tracer = new Tracer()
+    mockSpan = {
+      setTag: this.sandbox.spy(),
+      log: this.sandbox.spy(),
+      finish: this.sandbox.spy()
+    }
+
+    this.sandbox.stub(cls, 'startRootSpan').callsFake(() => mockSpan)
+
+    instrumentation.patch(express, tracer)
+  })
+
+  afterEach(() => {
+    instrumentation.unpatch(express)
+  })
+
+  describe('#patch', () => {
+    it('should create a span without parent', async () => {
+      // test
+      const app = express()
+      app.get('/', (req, res) => res.send('ok'))
+
+      await request(app)
+        .get('/')
+        .expect(200)
+        .end()
+
+      expect(cls.startRootSpan).to.be.calledWith(tracer, instrumentation.OPERATION_NAME)
+
+      expect(mockSpan.setTag).to.be.calledWith(Tags.HTTP_URL, 'http://127.0.0.1/')
+      expect(mockSpan.setTag).to.be.calledWith(Tags.HTTP_METHOD, 'GET')
+      expect(mockSpan.setTag).to.be.calledWith(Tags.SPAN_KIND_RPC_SERVER, true)
+      expect(mockSpan.log).to.be.calledWith({ peerRemoteAddress: '::ffff:127.0.0.1' })
+      expect(mockSpan.setTag).to.be.calledWith(instrumentation.TAG_REQUEST_PATH, '/')
+      expect(mockSpan.setTag).to.be.calledWith(Tags.HTTP_STATUS_CODE, 200)
+      expect(mockSpan.finish).to.have.callCount(1)
+    })
+
+    it('should create a span with parent', async () => {
+      const headers = {}
+      const parentSpan = tracer.startSpan('http_request')
+      tracer.inject(parentSpan, headers)
+
+      const app = express()
+      app.get('/', (req, res) => res.send('ok'))
+
+      await request(app)
+        .get('/')
+        .headers(headers)
+        .expect(200)
+        .end()
+
+      expect(cls.startRootSpan).to.be.calledWith(tracer, instrumentation.OPERATION_NAME, parentSpan.context())
+    })
+
+    it('should set error tag for > 3xx statu code', async () => {
+      const app = express()
+      app.get('/', (req, res) => {
+        res.statusCode = 400
+        res.send('ok')
+      })
+
+      await request(app)
+        .get('/')
+        .expect(400)
+        .end()
+
+      expect(mockSpan.setTag).to.be.calledWith(Tags.HTTP_STATUS_CODE, 400)
+      expect(mockSpan.setTag).to.be.calledWith(Tags.ERROR, true)
+      expect(mockSpan.finish).to.have.callCount(1)
+    })
+  })
+})