[tests] add a new "test:quick" yarn target

This will use the `babel-jest` transformer instead of the `ts-jest` one.
Babel won't perform typescript type checks and this will therefore run
faster.

README.md

@@ -32,7 +32,15 @@ on a change:
 yarn test:unit --watchAll
 ```
 
-`yarn test:unit` executes karma with rollup preprocessors for transpilation and bundling.
+Finally, you can deactivate typescript checks to run tests quicker:
+
+```bash
+yarn test:quick
+```
+
+This can be useful to accelerate your development cycle temporarily when
+developing a new feature or fixing a bug. Under the hood, this will use the
+`babel-jest` transformer on typescript files instead of `ts-jest`.
 
 ### Lints and fixes files
 

jest.config.js

@@ -8,7 +8,7 @@ module.exports = {
   },
   transform: {
     '^.+\\.vue$': 'vue-jest',
-    '^.+\\.ts$': 'ts-jest',
+    '^.+\\.ts$': process.env.VQB_QUICKTEST ? 'babel-jest' : 'ts-jest',
   },
   transformIgnorePatterns: ['/node_modules/', 'tests/*.js', 'playground/*'],
   collectCoverage: true,

package.json

@@ -10,6 +10,7 @@
     "playground": "concurrently \"yarn:build-bundle --watch\" \"node playground/server.js\"",
     "storybook": "start-storybook -p 9001 -c .storybook",
     "storybook:bundle": "rollup -c .storybook/rollup.config.js",
+    "test:quick": "VQB_QUICKTEST=1 jest",
     "test:unit": "jest",
     "tdd": "jest --watchAll"
   },