fails:Hash#reject returns a new hash removing keys for which the block yields true
fails:Hash#reject is equivalent to hsh.dup.delete_if
fails:Hash#reject returns subclass instance for subclasses
fails:Hash#reject taints the resulting hash
fails:Hash#reject processes entries with the same order as reject!
fails:Hash#reject returns an Enumerator if called on a non-empty hash without a block
fails:Hash#reject returns an Enumerator if called on an empty hash without a block
fails:Hash#reject returns an Enumerator if called on a frozen instance
fails:Hash#reject! removes keys from self for which the block yields true
fails:Hash#reject! is equivalent to delete_if if changes are made
fails:Hash#reject! returns nil if no changes were made
fails:Hash#reject! processes entries with the same order as delete_if
fails:Hash#reject! raises a RuntimeError if called on a frozen instance that is modified
fails:Hash#reject! raises a RuntimeError if called on a frozen instance that would not be modified
fails:Hash#reject! returns an Enumerator if called on a non-empty hash without a block
fails:Hash#reject! returns an Enumerator if called on an empty hash without a block
fails:Hash#reject! returns an Enumerator if called on a frozen instance
