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
- AnalysisIntermediateNew
Apply the SQALE Method to a Telecom OSS Codebase
Configure SonarQube's quality profiles to match the SQALE model's 8 characteristics (testability, reliability, changeability, efficiency, security, maintainability, portability,…
- Sqale Method
- Technical Debt
- Code Quality
Technical Debt Management - 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
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 - 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 Orchestration
- Autoscaling
Machine Learning at Scale Practice your coursework on real scenarios.
Every challenge is shaped from real industry context — not generic exercises. The work mirrors what your degree prepares you for.
Why Ewance
- 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 - 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, …
- Experimental Design
- A/B Testing
- Metric Design
Machine Learning in Practice - 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
- Mentorship & Coaching
- Process Mapping
Software Construction - 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…
- Systems Language Proficiency (Go, Rust, C++)
- Inheritance
- Polymorphism
Object-Oriented Programming and Design - 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.
- AnalysisBeginnerNew
A/B Test Landing Page for a 40-Person SaaS Scale-Up
You are a marketing analyst at TaskFlow. You have a dataset of 10,000 visitors with columns: group (control/variant), converted (yes/no), time on page (seconds), and device type…
- Hypothesis Testing
- A/B Testing
- Chi Square Test
Statistics for Business - 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 - 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 - CodeBeginnerNew
Refactor a Tangled Java Pricing Engine With Design Patterns
Start from a provided Java 21 codebase with the legacy PricingEngine class, 38 example fixtures (input cart, expected price), and one failing test demonstrating a bug from last …
- Python Or Javascript
- Design Patterns
- Refactoring
Object-Oriented Programming and Design 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
- 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 - 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 - 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 - 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 - 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 - 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
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 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 …
- Static Analysis
- Codeql
- Data Flow Analysis
Program Analysis - 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 - 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 - 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 - 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
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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