empty array when the argument is null or empty array', function() {
unique(null).should.be.eql...([]);
unique([]).should.be.eql([]);
});
it('should return a new array of uniqued items...uniArr.should.have.length(4);
uniArr.should.containDeep([1, 2, 3, 4]);
testArr.should.be.eql...array when the argument is not an array', function() {
unique({
length: 1
}).should.be.eql...});
it('should return a stable array', function() {
unique([2, 1, 3, 1, 2, 2, 1, 4]).should.be.eql