Junior Programmer case studies
Junior Programmer · Put your knowledge to work in context.
The Junior Programmer certification is an entry-level credential for people in their first year or two of writing code: students, career changers, and self-taught developers who want independent evidence that they can build working programs rather than only recite syntax. It tests breadth over depth. Expect questions on variables, data types, operators and expressions; conditional logic and loops; functions, parameters and scope; arrays, lists, maps and string manipulation; the vocabulary of classes, objects, attributes, methods and inheritance; reading an error message and writing a basic test; opening, reading and writing files with a standard library; and simple searching and sorting with a rough sense of why one approach is slower than another. A small slice covers everyday tooling - an editor or IDE, the command line, and version control basics such as commits, branches and diffs. The Junior Programmer case studies are 5 cases and about 4,140 words.
1The nightly fraud job that never ends
Priya maintains a nightly Python job for an online store. It walks through that day's orders and flags any order with a total below £25 for fraud review.
856 words, about 4 min2The discount that leaks between customers
Marco is adding a discount feature to a checkout library used by a single-process web app. He writes def apply discount(total, percent, rules=[]) , which appends a human-readable 'discount applied' entry to rules and returns the new total; rules is used as an audit trail.
789 words, about 4 min3The export that takes 42 seconds and keeps the wrong email
A marketing team runs a Python export every morning. subscribers holds 20,000 emails in send order.
751 words, about 4 min4Zero records written, exit code 0
Sam inherits a nightly importer that pulls 5,000 records from a partner API, validates them, and writes them to a warehouse. The retry wrapper is for attempt in range(3): try: return call(); except Exception: time.sleep(1) .
860 words, about 4 min5The 38 MB commit and the conflict resolved with 'ours'
Aisha is on a four-person team using a shared main branch on a hosted Git remote. Yesterday she committed a 38 MB customers.csv containing 5,000 email addresses and, inside a config file, a database password, then pushed and merged to main .
884 words, about 4 min