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
Build a Lexer and Parser for a Domain Query Language
Take the 1-page grammar sketch and the 12,000-query corpus (anonymized). Hand-write a lexer that emits tokens with source positions (line and column). Build a recursive-descent …
- Lexing
- Recursive Descent Parsing
- Abstract Syntax Trees
Compiler Construction - 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…
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Introduction to Computer Security - CodeIntermediateNew
Build a CodeQL Query Pack to Catch Logging-of-PII
Use CodeQL to write queries for Java and Python that detect data flow from PII sources (request parameters, database columns marked PII, user-profile fields) into logging sinks …
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Program Analysis - StrategyBeginnerNew
Code Review Bootcamp for an Early-Stage Mobile Team
Read the team's last 100 merged PRs (export provided) and tag the 10 worst review threads (rubber-stamp, bikeshed, missing context). Draft a 4-page code-review guideline coverin…
- Code Review
- Team Coaching
- Process Design
Software Construction 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
Build a Technical Debt Register for a Legacy Banking Monolith
Run 8 structured 45-minute engineer interviews (template provided) capturing one debt item per pain point with reproducible evidence. Run SonarQube against the monolith for a qu…
- Technical Debt
- Debt Quadrant
- Code Quality
Technical Debt Management - 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
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- Metric Design
LLM Application Development - AnalysisBeginnerNew
Right-Size a Real-Time Recommendation Serving Cluster
You receive 7 days of request-level telemetry (timestamp, latency, error code, pod) plus the existing Horizontal Pod Autoscaler (HPA) and node-group configs. Analyze traffic pat…
- Model Serving
- Kubernetes
- Autoscaling
Machine Learning at Scale - 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
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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.
- 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
- Spark
Data Mining and Information Retrieval - 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…
- Java
- Design Patterns
- Oo Design
Object-Oriented Programming and Design - 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 - 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
- Experiment Design
Prompt Engineering 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
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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…
- Java
- Oo Design
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Object-Oriented Programming and Design - CodeIntermediateNew
Build a Dataflow-Based Dead-Code Detector for a Python Monorepo
Build a Python tool using libcst (or ast + jedi) that constructs a call graph across the monorepo. Account for indirect references (entry points in setup.py / pyproject.toml, dy…
- Dataflow Analysis
- Ast
- Call Graph
Program Analysis - 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 - 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 - CodeIntermediateNew
Containerized Model Inference on Kubernetes for a Fintech
You receive a pre-trained credit-risk model (a LightGBM model file) and a sample request payload. Containerize a FastAPI inference service, deploy to EKS or GKE (a single-zone c…
- Kubernetes
- Containerization
- Autoscaling
Cloud Computing for Data and ML - CodeIntermediateNew
Build a Forgetting-Curve-Aware Spaced-Repetition Engine
You receive 6 months of practice logs from 8,000 learners (item, timestamp, response correctness, response latency). Fit a learner-personalized forgetting model (logistic per-it…
- Spaced Repetition
- Personalization
- Behavioral Data
AI in Education and Learning Analytics - DesignBeginnerNew
A/B-Test a Recommender Improvement Without Breaking Trust
You receive offline-evaluation results for both the production and candidate models plus aggregate metrics from the last 12 weeks (recipe views, save rate, weekly active users, …
- Experiment Design
- Ab Testing
- Metric Design
Machine Learning in Practice - 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 - CodeBeginnerNew
Build and Ship a Bug-Tracker MVP with Full CI/CD
Week 1: write a 1-page SRS + Figma wireframes for 5 screens (login, bug list, bug detail, file bug, dashboard). Week 2-3: implement with Next.js + Supabase + Tailwind, with unit…
- Full Stack Development
- Requirements Engineering
- Ci Cd
Software Engineering Foundations - CodeBeginnerNew
Design and Implement a C++ Telemetry Aggregator With Inheritance
Implement a TelemetrySource abstract base class with virtual sample() and timestamp() methods, 6 concrete subclasses (one per sensor family), and a TelemetryBus that polymorphic…
- Cpp
- Inheritance
- Polymorphism
Object-Oriented Programming and Design - CodeSeniorNew
Abstract-Interpretation-Based Configuration Validator for a SaaS Platform
Define an abstract domain capturing relations between configuration fields (e.g. 'if billing.plan = enterprise then features.audit_log = true'). Implement an abstract-interpreta…
- Abstract Interpretation
- Static Analysis
- Rust Programming
Program Analysis - AnalysisFoundationalNew
Optimize Ad Spend for Munich D2C Cosmetics Brand
You are given a CSV dataset with 10,000 rows of ad performance data including date, campaign, audience segment, creative type, impressions, clicks, conversions, and spend. Your …
- A B Testing
- Regression Analysis
- Data Cleaning
Marketing Analytics
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.
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