ci: produce jest xml reports only in azure pipelines (#10160)

* test: do not report coverage unless in CI

In #10128, we added test report tasks to Azure pipelines. Unfortunately,
this adds some additional overhead and coverage type stuff in _local_
development that we probably don't want.

This PR addresses this issue, and conditionally detects whether running
in CI. If running in CI (e.g. Azure Pipelines, Circle, etc.) it will add
the additional coverage reporter and coverage functionality.

Note: this is currently blocked by watson/ci-info#22

* add GENERATE_JEST_REPORT env var and use it with azure pipelines

* use var to hold normalized (boolean) val from env var

.gitignore

@@ -16,6 +16,7 @@ lib-cov
 
 # Coverage directory used by tools like istanbul
 coverage
+junit.xml
 
 # Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
 .grunt

azure-pipelines.yml

@@ -15,6 +15,8 @@ steps:
   - script: yarn bootstrap
 
   - script: yarn test
+    env:
+      GENERATE_JEST_REPORT: true
 
   - task: PublishTestResults@2
     displayName: "Publish Test Results"

jest.config.js

@@ -13,6 +13,7 @@ const builtTestsDirs = pkgs
 const distDirs = pkgs.map(p => path.join(p, `dist`))
 const ignoreDirs = [].concat(gatsbyBuildDirs, builtTestsDirs, distDirs)
 const coverageDirs = pkgs.map(p => path.join(p, `src/**/*.js`))
+const useCoverage = !!process.env.GENERATE_JEST_REPORT
 
 module.exports = {
   notify: true,
@@ -31,7 +32,7 @@ module.exports = {
   moduleNameMapper: {
     "^highlight.js$": `<rootDir>/node_modules/highlight.js/lib/index.js`,
   },
-  collectCoverage: true,
+  collectCoverage: useCoverage,
   coverageReporters: [`json-summary`, `text`, `html`, `cobertura`],
   coverageThreshold: {
     global: {
@@ -42,5 +43,5 @@ module.exports = {
     },
   },
   collectCoverageFrom: coverageDirs,
-  reporters: [`default`, `jest-junit`],
+  reporters: [`default`].concat(useCoverage ? `jest-junit` : []),
 }

package.json

@@ -22,8 +22,8 @@
     "glob": "^7.1.1",
     "husky": "1.1.1",
     "jest": "^23.5.0",
-    "jest-junit": "^5.0.0",
     "jest-cli": "^23.5.0",
+    "jest-junit": "^5.0.0",
     "lerna": "^3.3.0",
     "lint-staged": "^8.0.4",
     "npm-run-all": "4.1.5",