Configure Jest to generate JUnit formatted reports

Jest is able to generate JUnit formatted reports using the
jest-junit (1) package. It has been defined in the main configuration
file as additional reporter next to the `default` report format.
See Circle CI's documentation about to how to collect test data (2) for
more details about setups with Jest.

References:
  (1) https://github.com/codecov/jest-junit
  (2) https://circleci.com/docs/2.0/collect-test-data/#jest

GH-44

.circleci/config.yml

@@ -31,6 +31,8 @@ commands:
           path: ./public
       - store_artifacts:
           path: ./node_modules.tgz
+      - store_tests_results:
+          path: ./build/reports/junit
       - codecov/upload:
           file: ./build/reports/coverage/coverage-final.json
           flags: unit
@@ -79,8 +81,8 @@ commands:
           name: Lint
           command: npm run lint
       - run:
-          name: Run tests with coverage
-          command: npm run test:cov
+          name: Run tests with coverage in CI mode
+          command: npm run test:ci
 
 jobs:
   nodejs-v8:
@@ -115,6 +117,9 @@ workflows:
   version: 2.1
   build-multi-version:
     jobs:
-      - nodejs-v8
-      - nodejs-v10
-      - nodejs-latest
+      - nodejs-v8:
+          context: nord-docs-ctx
+      - nodejs-v10:
+          context: nord-docs-ctx
+      - nodejs-latest:
+          context: nord-docs-ctx

jest.config.js

@@ -13,10 +13,11 @@
  * @author Sven Greb <[email protected]>
  * @see https://jestjs.io/docs/en/configuration
  * @see https://www.gatsbyjs.org/docs/testing
+ * @see https://circleci.com/docs/2.0/collect-test-data/#jest
  * @since 0.1.0
  */
 
-const { BASE_DIR_BUILD_REPORTS_COVERAGE } = require("./src/config/internal/constants");
+const { BASE_DIR_BUILD_REPORTS_COVERAGE, BASE_DIR_BUILD_REPORTS_JUNIT } = require("./src/config/internal/constants");
 
 module.exports = {
   /*
@@ -70,6 +71,20 @@ module.exports = {
    */
   modulePaths: ["<rootDir>/test/__utils__"],
 
+  /*
+   * An array of module names to specify which reporters will be used.
+   */
+  reporters: [
+    "default",
+    [
+      "jest-junit",
+      {
+        outputDirectory: `${BASE_DIR_BUILD_REPORTS_JUNIT}`,
+        outputName: "jest.xml"
+      }
+    ]
+  ],
+
   /*
    * The paths to modules that run some code to configure or set up the testing environment before each test.
    * The `___loader` shim is a global function used by internal Gatsby APIs.

package.json

@@ -38,8 +38,10 @@
     "lint": "npm-run-all lint:*",
     "lint:js": "eslint --ext .js,.jsx .",
     "lint:md": "remark --no-stdout . \".github/**/*.md\"",
+    "report:js:junit": "eslint --ext .js,.jsx --format junit -o ./build/reports/junit/eslint.xml .",
     "serve": "gatsby serve",
     "test": "jest",
+    "test:ci": "jest --ci --coverage",
     "test:cov": "jest --coverage",
     "test:watch": "jest --watch"
   },
@@ -67,6 +69,7 @@
     "identity-obj-proxy": "3.0.0",
     "jest": "23.6.0",
     "jest-dom": "2.1.1",
+    "jest-junit": "5.2.0",
     "lint-staged": "8.0.5",
     "npm-run-all": "4.1.3",
     "prettier": "1.15.2",

src/config/internal/constants.js

@@ -70,6 +70,14 @@ const BASE_DIR_BUILD_REPORTS = `${BASE_DIR_BUILD}/reports`;
  */
 const BASE_DIR_BUILD_REPORTS_COVERAGE = `${BASE_DIR_BUILD_REPORTS}/coverage`;
 
+/**
+ *  The relative path of the build base directory for JUnit reports starting from the project root.
+ *
+ * @constant {string}
+ * @since 0.1.0
+ */
+const BASE_DIR_BUILD_REPORTS_JUNIT = `${BASE_DIR_BUILD_REPORTS}/junit`;
+
 /**
  *  The relative path of the config base directory starting from the project root.
  *
@@ -109,6 +117,7 @@ module.exports = {
   BASE_DIR_BUILD,
   BASE_DIR_BUILD_REPORTS,
   BASE_DIR_BUILD_REPORTS_COVERAGE,
+  BASE_DIR_BUILD_REPORTS_JUNIT,
   BASE_DIR_CONFIG,
   BASE_DIR_CONTENT,
   BASE_DIR_PAGES,