fix(vitest): fix coverage not being reported when value is zero (#5681)

* fix(vitest): fix coverage not being reported when value is zero

* Add zero coverage test case

As drive-by improve the test to use async/await.

---------

Co-authored-by: Giamir Buoncristiani <giamir.buoncristiani@gmail.com>

Author: 2 people

integration-tests/ci-visibility/vitest-tests/coverage-test-zero.mjs

@@ -0,0 +1,8 @@
+import { describe, test, expect } from 'vitest'
+import { sum } from './sum'
+
+describe('code coverage', () => {
+  test('passes', () => {
+    expect(typeof sum === 'function').toBe(true)
+  })
+})

integration-tests/vitest/vitest.spec.js

@@ -47,6 +47,7 @@ const {
   TEST_RETRY_REASON_TYPES
 } = require('../../packages/dd-trace/src/plugins/util/test')
 const { DD_HOST_CPU_COUNT } = require('../../packages/dd-trace/src/plugins/util/env')
+const { once } = require('node:events')
 
 const NUM_RETRIES_EFD = 3
 
@@ -396,7 +397,7 @@ versions.forEach((version) => {
       const coverageProviders = ['v8', 'istanbul']
 
       coverageProviders.forEach((coverageProvider) => {
-        it(`reports code coverage for ${coverageProvider} provider`, (done) => {
+        it(`reports code coverage for ${coverageProvider} provider`, async () => {
           let codeCoverageExtracted
           const eventsPromise = receiver
             .gatherPayloadsMaxTimeout(({ url }) => url.endsWith('/api/v2/citestcycle'), (payloads) => {
@@ -415,7 +416,7 @@ versions.forEach((version) => {
                 ...getCiVisAgentlessConfig(receiver.port),
                 NODE_OPTIONS: '--import dd-trace/register.js -r dd-trace/ci/init',
                 COVERAGE_PROVIDER: coverageProvider,
-                TEST_DIR: 'ci-visibility/vitest-tests/coverage-test*'
+                TEST_DIR: 'ci-visibility/vitest-tests/coverage-test.mjs'
               },
               stdio: 'inherit'
             }
@@ -428,20 +429,72 @@ versions.forEach((version) => {
             testOutput += chunk.toString()
           })
 
-          childProcess.on('exit', () => {
-            eventsPromise.then(() => {
-              const linePctMatch = testOutput.match(linePctMatchRegex)
-              const linesPctFromNyc = linePctMatch ? Number(linePctMatch[1]) : null
-
-              assert.equal(
-                linesPctFromNyc,
-                codeCoverageExtracted,
-                'coverage reported by vitest does not match extracted coverage'
-              )
-              done()
-            }).catch(done)
+          await Promise.all([
+            once(childProcess, 'exit'),
+            eventsPromise
+          ])
+
+          const linePctMatch = testOutput.match(linePctMatchRegex)
+          const linesPctFromNyc = Number(linePctMatch[1])
+
+          assert.strictEqual(
+            linesPctFromNyc,
+            codeCoverageExtracted,
+            'coverage reported by vitest does not match extracted coverage'
+          )
+        })
+      })
+
+      it('reports zero code coverage for instanbul provider', async () => {
+        let codeCoverageExtracted
+        const eventsPromise = receiver
+          .gatherPayloadsMaxTimeout(({ url }) => url.endsWith('/api/v2/citestcycle'), (payloads) => {
+            const events = payloads.flatMap(({ payload }) => payload.events)
+
+            const testSession = events.find(event => event.type === 'test_session_end').content
+
+            codeCoverageExtracted = testSession.metrics[TEST_CODE_COVERAGE_LINES_PCT]
           })
+
+        childProcess = exec(
+          './node_modules/.bin/vitest run --coverage',
+          {
+            cwd,
+            env: {
+              ...getCiVisAgentlessConfig(receiver.port),
+              NODE_OPTIONS: '--import dd-trace/register.js -r dd-trace/ci/init',
+              COVERAGE_PROVIDER: 'istanbul',
+              TEST_DIR: 'ci-visibility/vitest-tests/coverage-test-zero.mjs'
+            },
+            stdio: 'inherit'
+          }
+        )
+
+        childProcess.stdout.on('data', (chunk) => {
+          testOutput += chunk.toString()
         })
+        childProcess.stderr.on('data', (chunk) => {
+          testOutput += chunk.toString()
+        })
+
+        await Promise.all([
+          once(childProcess, 'exit'),
+          eventsPromise
+        ])
+
+        const linePctMatch = testOutput.match(linePctMatchRegex)
+        const linesPctFromNyc = Number(linePctMatch[1])
+
+        assert.strictEqual(
+          linesPctFromNyc,
+          codeCoverageExtracted,
+          'coverage reported by vitest does not match extracted coverage'
+        )
+        assert.strictEqual(
+          linesPctFromNyc,
+          0,
+          'zero coverage should be reported'
+        )
       })
     }
     // maybe only latest version?

packages/datadog-plugin-vitest/src/index.js

@@ -349,7 +349,7 @@ class VitestPlugin extends CiPlugin {
         this.testModuleSpan.setTag('error', error)
         this.testSessionSpan.setTag('error', error)
       }
-      if (testCodeCoverageLinesTotal) {
+      if (testCodeCoverageLinesTotal !== undefined) {
         this.testModuleSpan.setTag(TEST_CODE_COVERAGE_LINES_PCT, testCodeCoverageLinesTotal)
         this.testSessionSpan.setTag(TEST_CODE_COVERAGE_LINES_PCT, testCodeCoverageLinesTotal)
       }