Add `_.lowerCase`, `_.lowerFirst`, `_.toLower`, `_.toUpper`, `_.upperCase`, `_.upperFirst` tests.
Add `_.lowerCase`, `_.lowerFirst`, `_.toLower`, `_.toUpper`, `_.upperCase`, `_.upperFirst` tests.

Xotic750/lodash,rlugojr/lodash,Xotic750/lodash,tonyonodi/lodash,beaugunderson/lodash,boneskull/lodash,tonyonodi/lodash,msmorgan/lodash,Xotic750/lodash,boneskull/lodash,rlugojr/lodash,steelsojka/lodash,msmorgan/lodash,beaugunderson/lodash,steelsojka/lodash