Computer Science
Testing & QA Challenges
Testing & QA challenges put you behind the safety net that lets software ship with confidence. You'll develop skills in Software Testing, Unit Testing, and Automated Testing, build End-to-end testing flows, and read Coverage Reports to find the gaps that matter before users do.
From there you'll handle the harder edges — Test architecture, Test pyramid discipline, Contract testing, and Load Testing — alongside Static Analysis, AI-assisted test generation, and regulated practices like ISO 17025 calibration and CAPA workflows. Each challenge you solve earns a verified credential you can share with recruiters.
Recommended Challenges
- CodeBeginnerNew
Add Constant Folding and Dead Code Elimination to a Toy Compiler
Fork the repo, read the IR specification (3-address code, register-based, documented in /docs/ir.md). Implement constant folding as an IR-to-IR pass: any operation on literal op…
- Intermediate Representation
- Constant Folding
- Dead Code Elimination
Compiler Construction - CodeBeginnerNew
Design a Domain Model for a Library Loan System (Java)
Implement, in Java 21, an Item type hierarchy (Book, AudioBook, Periodical, EquipmentLoan — each with sub-type-specific rules), Member with eligibility logic, Loan as an aggrega…
- Python Or Javascript
- Oo Design
- Domain Modeling
Object-Oriented Programming and Design - AnalysisIntermediateNew
A/B Testing for a 40-Person SaaS Scale-up Moving to Enterprise
You are a data analyst at TaskFlow. You are given the raw A/B test data (visitor logs, conversions, and downstream sales data). Your task is to perform a rigorous analysis: chec…
- A/B Testing
- Statistical Analysis
- Bayesian Methods
Data Science for Business - CodeSeniorNew
Detect Use-After-Free with Pointer Analysis in a C++ Codebase
Build the codebase with compilation database (compile_commands.json). Write a custom Clang static-analyzer checker (or extend an existing one) that flags resource-handle uses af…
- Pointer Analysis
- Static Analysis
- Use After Free
Program Analysis Practice your coursework on real scenarios.
Every challenge is shaped from real-world context — not generic exercises. The work mirrors what your degree prepares you for.
Why Ewance
- AnalysisIntermediateNew
Frequent-Itemset Mining on a Grocery Retailer's Basket History
Load 18 months of basket-level transaction data (Parquet, around 92 GB) into a Spark cluster. Run FP-growth at support thresholds tuned per category (food vs household vs fresh)…
- Frequent Itemset Mining
- Fp Growth
- Apache Spark
Data Mining and Information Retrieval - CodeBeginnerNew
Build a Secure-Coding Linter Ruleset for a Backend Team
Receive the last 12 security-review findings, 3 representative repos (Node.js + TypeScript), and access to a CI pipeline (GitHub Actions). Build a custom Semgrep ruleset (or ESL…
- Secure Coding
- Static Analysis
- Semgrep
Introduction to Computer Security - AnalysisIntermediateNew
Diagnose Modern Transport-Protocol Performance for an OTT Streamer
Receive the current delivery architecture (HTTP/2 origin + CDN), 4 weeks of Conviva-style QoE (quality of experience) metrics, and access to a synthetic-client harness (Linux + …
- Quic Http3
- Network Measurement
- Transport Protocols
Advanced Computer Networks - CodeBeginnerNew
Replace Raw Pointers with Smart Pointers in a Game-Engine Module
Audit the 18k-line module for raw-pointer ownership patterns (owning, borrowing, shared). Refactor in 4 phases: (1) introduce unique_ptr for clearly-owning sites, (2) shared_ptr…
- Cpp Programming
- Manual Memory Management
- Pointers
Imperative and Low-Level Programming - Browse challenges
Explore role
Product Manager
Ship product that solves real user problems. Combine user research, prototyping, and stakeholder alignment to turn ambiguous briefs into measurable wins — the role at the centre of modern software teams.
- CodeIntermediateNew
Debug a Race Condition in a Real-Time Collaboration Service
Build a deterministic load-test harness (k6 or Playwright) that reproduces the corruption within 3 attempts on a clean local stack. Capture traces with OpenTelemetry to localize…
- Debugging
- Concurrency
- Load Testing
Software Construction - DesignIntermediateNew
Design an Adaptive UI for a Streaming-Platform Recommender
Design 3 adaptive layout variants triggered by session-intent signals (time of day, last-3-session pattern, device class) — without retraining the recommender. Build a high-fide…
- Adaptive Interfaces
- Interaction Design
- A/B Testing
Advanced Human-Computer Interaction - CodeIntermediateNew
Apply Hexagonal Architecture to a Payments Microservice
Design the settlement domain in pure Kotlin (no Spring imports, no framework annotations). Define ports for: payment-network adapter (one inbound per network — SEPA, Faster Paym…
- Hexagonal Architecture
- Ports And Adapters
- Kotlin Programming
Domain-Driven Design - CodeIntermediateNew
Build a Canary Rollout for a Production Recommender
Pick a serving stack (Triton, Seldon Core, KServe, or BentoML). Implement two-model traffic splitting with a configurable percentage (start at 5%). Wire up online metric collect…
- Canary Deployment
- Kubernetes Orchestration
- A/B Testing
ML Engineering and Production ML Build a verifiable portfolio.
Submissions become evidence. Reviewers with shipping experience score against a rubric; the result becomes a credential anyone can verify.
Why Ewance
- CodeIntermediateNew
Code Review and Refactoring of a Legacy E-Commerce Module
You are given a codebase (Java/Spring Boot) of the order module. Perform a static analysis, document issues (e.g., god classes, tight coupling), and write a refactoring proposal…
- Code Review
- Refactoring
- Python Or Javascript
Software Engineering and Quality Assurance - AnalysisBeginnerNew
Run an A/B Test on Two System Prompts for a Sales Email Assistant
You will (1) design the A/B test (random assignment by rep_id, 50/50 split, 2-week duration), (2) instrument three primary metrics: reply rate (event-based), average tokens per …
- Prompt Evaluation
- A/B Testing
- Metric Design
LLM Application Development - AnalysisIntermediateNew
MCMC for Conversion-Funnel A/B Testing at a Marketplace
You receive 6 weeks of per-visitor funnel data (visit, sign-up, trial start, trial-to-paid conversion) split by variant and by acquisition channel (organic, paid social, paid se…
- Mcmc
- Bayesian Hierarchical Models
- A/B Testing
Probabilistic Machine Learning - CodeIntermediateNew
Build a Hybrid Recommendation System for an Indie Streaming Catalog
Use the provided 6-month anonymized event log (around 320M play events, 1.4M unique users in the held-out cohort), audio embeddings (256-d), and track metadata. Implement (1) an…
- Recommendation Systems
- Collaborative Filtering
- Content Based Recommendation
Data Mining and Information Retrieval - CodeBeginnerNew
Add a Test Harness to an Untested Open-Source CLI
Fork the repo (test mirror provided), set up Vitest with coverage and a CI workflow that fails under 75 percent on the targeted modules. Write characterization tests first (asse…
- Unit Testing
- Integration Testing
- Test Coverage
Software Construction - CodeBeginnerNew
Build an End-to-End Test Suite for a Checkout Flow
Inventory the last 6 months of production checkout incidents (anonymized export provided). Pick the top 7 user journeys (1 happy path + 6 highest-incident edge cases) and write …
- End To End Testing
- Playwright
- Ci Cd
Software Testing and Quality Assurance - DesignSeniorNew
Migrate a 600K-LOC Monolith to a Modular Monolith
Run static dependency analysis on the monolith (using Packwerk + custom Ruby AST scripts, both available) to surface the current implicit modules and the worst cross-module depe…
- Large Scale Codebases
- Modular Monolith
- Static Analysis
Advanced Software Engineering - CodeIntermediateNew
Build a Hybrid Recommender for a Niche Consumer-AI Music App
You receive listening events (around 240 million plays) plus a content embedding per track (audio + curator tags). Build a collaborative filtering model (ALS or implicit-feedbac…
- Recommender Systems
- Collaborative Filtering
- Content Based Filtering
Data Mining and Knowledge Discovery - CodeSeniorNew
Build a Symbolic-Execution-Based Test Generator for a Library
Pick KLEE for the symbolic-execution engine. Build LLVM bitcode for the library's C99 build target. Define symbolic inputs for the public parsing API (date strings up to 32 char…
- Symbolic Execution
- Klee
- Test Generation
Program Analysis - AnalysisSeniorNew
Cost-Quality Prompt Optimization at Scale
You receive 2,000 labeled code snippets (human rater consensus score 1-5) and budget for at most 8,000 API calls across the optimization run. Run a factorial sweep of 3 prompt s…
- Prompt Optimization
- Cost Quality Tradeoff
- Experimental Design
Prompt Engineering - CodeBeginnerNew
Build a Plugin-Based Notification Framework With Observer + Factory
Implement, in Java 21: an EventBus that supports typed subscriptions, a NotificationChannel interface with concrete subtypes (Push, Email, InApp, SMS), an AbstractChannelFactory…
- Python Or Javascript
- Design Patterns
- Oo Design
Object-Oriented Programming and Design - CodeIntermediateNew
Stand Up Contract Testing for a Microservices Backend
Inventory the 18 services and pick the 6 producer-consumer pairs with the most staging breakages in the last 90 days. Stand up a Pact broker (self-hosted or PactFlow trial). For…
- Contract Testing
- Pact
- Microservices Patterns
Software Testing and Quality Assurance
How it works
From brief to credential, in six steps.
Step 01
Browse challenges aligned to your studies.
Step 02
Accept the one that fits your goals.
Step 03
Work through it with AI Copilot guidance.
Step 04
Submit for structured evaluation.
Step 05
Earn a verified credential.
Step 06
Add it to LinkedIn with one click.
Related skill families
Browse all skillsIndustry teams behind a decade of practitioner briefs
Hiring from this pool?
Sponsor a challenge and meet candidates through actual work.
Industry teams can shape briefs around the skills they hire for, then evaluate students on rubric-scored deliverables — not resumes.