test(browser): always build dist bundles for browser testing

Author: mbroadst

package.json

@@ -63,7 +63,7 @@
     "docs": "jsdoc2md --heading-depth 3 --template tools/README.hbs --plugin dmd-clear --files lib/bson.js lib/extended_json.js > README.md",
     "test": "npm run-script test-node && npm run-script test-browser",
     "test-node": "mocha ./test/node",
-    "test-browser": "karma start",
+    "test-browser": "npm run-script build && karma start",
     "build": "rollup -c",
     "lint": "eslint lib test",
     "format": "prettier --print-width 100 --tab-width 2 --single-quote --write 'test/**/*.js' 'lib/**/*.js'",