Current File : //proc/self/root/home/infra/fusioninventory/lib/lazy.js-0.5.1/spec/shuffle_spec.js
describe("shuffle", function() {
ensureLaziness(function() { Lazy(people).shuffle(); });
// Not 100% sure of a great way to do this, so... let's just go with a
// probabilistic test.
it("shuffles the collection", function() {
var shuffledCollections = Lazy.range(10)
.map(function() { return Lazy(people).shuffle().toArray(); })
.memoize();
var firstResult = shuffledCollections.first();
shuffledCollections.each(function(collection) {
// Verify the elements in the collection
var resorted = Lazy(collection)
.sortBy(Person.getAge)
.reverse()
.toArray();
expect(resorted).toEqual(people);
});
var differences = Lazy(people)
.map(function() { return 0; })
.toArray();
shuffledCollections.drop(1).each(function(collection) {
for (var i = 0; i < collection.length; ++i) {
if (collection[i] !== firstResult[i]) {
differences[i]++;
}
}
});
for (var i = 0; i < people.length; ++i) {
expect(differences[i]).toBeGreaterThan(0, 'All elements at ' + i + ' are the same!');
}
});
it("is unbiased", function() {
var firsts = Lazy.range(100)
.map(function() { return Lazy(people).shuffle().first(); })
.memoize();
expect(firsts.uniq().sortBy(Person.getName)).toComprise([
adam, daniel, david, happy, lauren, mary
]);
});
it("passes an index along with each element", function() {
expect(Lazy(people).shuffle()).toPassToEach(1, [0, 1, 2, 3, 4, 5]);
});
});
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