Add `Stack` test.
Add `Stack` test.

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