project: Add jest watcher for quicker tests runs during development.

Author: microbit-carlos

config/jest.config.js

@@ -18,6 +18,10 @@ const config = {
     },
   },
   setupFiles: ['<rootDir>/config/setup-tests.js'],
+  watchPlugins: [
+    'jest-watch-typeahead/filename',
+    'jest-watch-typeahead/testname',
+  ],
 };
 
 module.exports = config;

package-lock.json

@@ -32,6 +32,7 @@
     "prebuild": "npm run cleanup && npm run verify",
     "build": "tsc && rollup -c config/rollup.config.js",
     "test": "jest -c ./config/jest.config.js",
+    "test:watch": "npm t -- --watch",
     "test:coverage": "npm t -- --verbose --coverage",
     "test:ci": "npm t -- --ci",
     "validate-js": "tsc -p ./config",
@@ -61,6 +62,7 @@
     "@types/node": "~13.11.1",
     "@types/prettier": "~2.0.0",
     "jest": "~25.3.0",
+    "jest-watch-typeahead": "~0.6.0",
     "prettier": "~2.0.4",
     "rollup": "~2.6.1",
     "rollup-plugin-babel": "~4.4.0",