Migrated tests to jest

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

test/reducedFilter/reducedFilter.js

@@ -1,8 +0,0 @@
-const reducedFilter = (data, keys, fn) =>
-data.filter(fn).map(el =>
-keys.reduce((acc, key) => {
-acc[key] = el[key];
-return acc;
-}, {})
-);
-module.exports = reducedFilter;