[ci-visibility] Fix jest bug when parent id is null (#2848)

integration-tests/ci-visibility.spec.js

@@ -93,6 +93,29 @@ testFrameworks.forEach(({
       await receiver.stop()
     })
 
+    if (name === 'jest') {
+      it('does not crash when jest is badly initialized', (done) => {
+        childProcess = fork('ci-visibility/run-jest-bad-init.js', {
+          cwd,
+          env: {
+            DD_TRACE_AGENT_PORT: receiver.port
+          },
+          stdio: 'pipe'
+        })
+        childProcess.stdout.on('data', (chunk) => {
+          testOutput += chunk.toString()
+        })
+        childProcess.stderr.on('data', (chunk) => {
+          testOutput += chunk.toString()
+        })
+        childProcess.on('message', () => {
+          assert.notInclude(testOutput, 'TypeError')
+          assert.include(testOutput, expectedStdout)
+          done()
+        })
+      })
+    }
+
     it('can run tests and report spans', (done) => {
       receiver.setInfoResponse({ endpoints: [] })
       receiver.payloadReceived(({ url }) => url === '/v0.4/traces').then(({ payload }) => {

integration-tests/ci-visibility/jestEnvironmentBadInit.js

@@ -0,0 +1,6 @@
+// eslint-disable-next-line
+require('dd-trace').init({
+  service: 'dd-trace-bad-init'
+})
+
+module.exports = require('jest-environment-node')

integration-tests/ci-visibility/run-jest-bad-init.js

@@ -0,0 +1,20 @@
+const jest = require('jest')
+
+const options = {
+  projects: [__dirname],
+  testPathIgnorePatterns: ['/node_modules/'],
+  cache: false,
+  maxWorkers: '50%',
+  testRegex: /test\/ci-visibility-test/,
+  runInBand: true,
+  testEnvironment: '<rootDir>/ci-visibility/jestEnvironmentBadInit.js'
+}
+
+jest.runCLI(
+  options,
+  options.projects
+).then(() => {
+  if (process.send) {
+    process.send('finished')
+  }
+})

packages/dd-trace/src/plugins/ci_plugin.js

@@ -128,10 +128,13 @@ module.exports = class CiPlugin extends Plugin {
       const suiteTags = {
         [TEST_SUITE_ID]: testSuiteSpan.context().toSpanId(),
         [TEST_SESSION_ID]: testSuiteSpan.context().toTraceId(),
-        [TEST_MODULE_ID]: testSuiteSpan.context()._parentId.toString(10),
         [TEST_COMMAND]: testSuiteSpan.context()._tags[TEST_COMMAND],
         [TEST_BUNDLE]: testSuiteSpan.context()._tags[TEST_COMMAND]
       }
+      if (testSuiteSpan.context()._parentId) {
+        suiteTags[TEST_MODULE_ID] = testSuiteSpan.context()._parentId.toString(10)
+      }
+
       testTags = {
         ...testTags,
         ...suiteTags