Migrated tests to jest

Used jest-codemods to migrate, will have to pass everything by hand before we can merge.

test/pluralize/pluralize.js

@@ -1,7 +0,0 @@
-const pluralize = (val, word, plural = word + 's') => {
-const _pluralize = (num, word, plural = word + 's') =>
-[1, -1].includes(Number(num)) ? word : plural;
-if (typeof val === 'object') return (num, word) => _pluralize(num, word, val[word]);
-return _pluralize(val, word, plural);
-};
-module.exports = pluralize;