Migrated tests to jest

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

test/unescapeHTML/unescapeHTML.js

@@ -1,13 +0,0 @@
-const unescapeHTML = str =>
-str.replace(
-/&|<|>|'|"/g,
-tag =>
-({
-'&': '&',
-'&lt;': '<',
-'&gt;': '>',
-'&#39;': "'",
-'&quot;': '"'
-}[tag] || tag)
-);
-module.exports = unescapeHTML;