test: add puppeteer config and run in band

examples/README.md

@@ -13,7 +13,7 @@ First the performance tests need baselining for the machine they are being run
 on. Check out the code prior to the change under test and run -
 
 ```bash
-npm run examples -- --updateSnapshot
+HEADLESS=false EXECUTABLE_PATH="path_to_chrome\chrome.exe" npm run examples -- --updateSnapshot
 ```
 
 At this stage the `*/__tests__/__snapshots__` files will have been updated
@@ -23,9 +23,12 @@ files with the visual output of the examples.
 Check out the code containing the change under test and run -
 
 ```bash
-npm run examples
+HEADLESS=false EXECUTABLE_PATH="path_to_chrome\chrome.exe" npm run examples
 ```
 
 Any errors at this stage should correlate with known changes to either the
 performance or visual output of the examples (please don't ignore
 non-determinism).
+
+It is advised that the `HEADLESS` and `EXECUTABLE_PATH` environment variables
+are set as puppeteer does not use the GPU in headless mode.

examples/jest-puppeteer.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+    launch: {
+        headless: process.env.HEADLESS !== 'false',
+        executablePath: process.env.EXECUTABLE_PATH
+    }
+};

package.json

@@ -14,7 +14,7 @@
     "screenshots": "lerna run screenshots --stream --concurrency 1",
     "start": "lerna run bundle && npm start --prefix ./packages/d3fc",
     "commitlint": "commitlint --from HEAD~1 to HEAD --verbose",
-    "examples": "cd examples && npx jest"
+    "examples": "cd examples && npx jest --runInBand"
   },
   "husky": {
     "hooks": {