Online Store Testing Tutorial: Cart, Checkout & Promo Code Bugs

Requirements

The shop is available in English, Russian, German, Spanish and French. Prices are in US dollars ($) in every language version.
Anyone can browse the catalog and product pages. Adding to the cart or the wishlist, and placing orders, requires signing in.
All data (users, carts, orders, reviews, stock) is stored in your browser. The Reset shop button in the Realbugz menu (the round «Rb» button in the top-left corner of the shop) deletes all of it and restores the initial stock. The same menu opens these requirements in a separate tab.
All pages are usable on a phone (screen width from 360 px) with no horizontal scrolling. On a phone the filters are hidden behind the Filters button and the navigation — behind the menu button.
The shop header contains the logo (leads to the catalog), search, Wishlist and Cart with item counters, and Sign in or the user's name (leads to the account).

The catalog contains 64 products in 8 categories.
A product card shows a photo, name, price (and the old price crossed out if there is a discount), rating, the Add to cart button and the wishlist button.
Products that are out of stock are marked "Out of stock" and cannot be added to the cart.
Search works by product name, is case-insensitive, ignores spaces at the beginning and end and starts from 2 characters. If nothing is found, the message "Nothing found" is shown.
Filters: category (several can be selected), price from / to (whole numbers from 0, "from" not greater than "to"; boundaries are inclusive — a product priced exactly at the boundary is shown), "In stock only".
Sorting: by popularity (default), price low to high, price high to low, name A–Z, rating.
Search, filters and sorting work together. 12 products per page with page numbers below.
After returning from a product page, filters, sorting and the page number are preserved.
When a guest clicks Add to cart or the wishlist button, the sign-in page opens; after signing in, the user returns to the page they came from.

Breadcrumbs: Catalog → Category → Product.
Photo, name, category, price, description and specifications.
Stock: "In stock: N pcs" or "Out of stock".
Quantity: from 1 to 10, but not more than the stock.
Clicking the wishlist button again removes the product from the wishlist.
Reviews: a rating from 1 to 5 stars and a text of 10–500 characters (spaces at the beginning and end are not counted). Only signed-in users can write a review, one review per product. The average rating is shown with one decimal place, next to the number of reviews.

Name: 2–30 characters, letters (Latin, including accented letters such as é, ü, ñ, and Cyrillic), spaces and hyphens.
Email: a valid format, unique (case-insensitive).
Password: 8–20 characters, at least one letter and one digit. There is a Show button.
Password confirmation must match the password.
The "I agree to the terms of use" checkbox is required.
Errors are shown under the field as soon as you leave it. After registration the user is signed in.
If the email or password is wrong, the message "Incorrect email or password" is shown (without specifying which one).
The user stays signed in after closing the tab, until they click Sign out.
Each user has their own cart and wishlist: after signing out they are hidden, after signing in they come back.

Each line shows a photo, name, price per item, quantity (− / + buttons and a field), line sum and a Remove button.
Quantity: from 1 to 10 and not more than the stock. Trying to set more shows a message "No more than 10 pcs of one item per customer" or "Only N pcs available".
Adding a product that is already in the cart increases its quantity (with the same limits).
An empty cart shows a message and a link to the catalog.
Delivery cost is calculated at checkout. All sums are rounded to cents.

Only one promo code per order. Letter case does not matter, spaces at the beginning and end are ignored.
TREK10 — 10% off, only for items without a discount.
SAVE15 — $15 off if the items total is $100 or more.
FREESHIP — free courier delivery (not express).
SUMMER24 — expired: the message "This promo code has expired" is shown.
An unknown code shows the message "Promo code not found".

Recipient (prefilled with the profile name), phone ("+" and 10–15 digits), city (2–50 characters), street and house (3–100 characters), ZIP code (5–6 digits) — required; comment for the courier — up to 200 characters, optional.
Delivery: store pickup — $0; courier — $10, free if the items total after discount is $150 or more; express — always $25.
Payment: "Card online" or "Cash on delivery".
One click on Place order creates exactly one order. The order gets a number like RB-10001 (in sequence), the cart is emptied, the promo code is reset and the stock is reduced.
Card payment is made on the order page while the status is "Awaiting payment": card number of 16 digits, expiry date MM/YY not in the past, CVV of 3 digits. Use the test card 4242 4242 4242 4242.

"Awaiting payment" — right after checkout with "Card online".
"Paid, packing" — after card payment, or right after checkout with "Cash on delivery".
"Shipped" — after "Paid, packing", when the order leaves the warehouse.
"Delivered" — after "Shipped", when the courier delivers the order.
"Cancelled" — the user clicked Cancel order; the stock is returned. An order can be cancelled only before it is shipped.
The order page shows the status history with date and time.

Profile: the name can be changed, the email cannot. Password change: current password, new password, confirmation.
My orders: number, date, total and status; newest first. Clicking an order opens its details.
Wishlist: product list, remove, add to cart.