Intermediate~3h
Clean Code & Refactoring in Low-Level DesignInterview Readiness Check
Eliminate code smells before they become design debt — naming, function size, Law of Demeter, God class, Feature Envy, Primitive Obsession, and the refactoring moves that fix each one.
code smellgod classfeature envydata clumplong methodextract methodmove methodLaw of DemeterLCOMnamingmagic numberrefactoringprimitive obsessionvalue objectswitch smelltestability
Learning path
What this module tests
- Conceptual understanding of clean code & refactoring fundamentals
- Trade-offs and design decisions in real system scenarios
- code smell and god class — applied knowledge
- Interview-style reasoning and explanation quality
Free to start
Take the Clean Code & Refactoring check →
10 questions · Dimension scoring · AI coach feedback · Shareable result
Test your knowledge — free →No credit card · Takes 10–15 min
Frequently asked questions
- What does the Clean Code & Refactoring check test?
- The check covers eliminate code smells before they become design debt — naming, function size, law of demeter, god class, feature envy, primitive obsession, and the refactoring moves that fix each one. Questions span beginner to advanced difficulty and test both conceptual understanding and practical trade-off reasoning.
- What keywords should I know for Clean Code & Refactoring?
- Key concepts include: code smell, god class, feature envy, data clump, long method, extract method, move method, Law of Demeter, LCOM, naming, magic number, refactoring, primitive obsession, value object, switch smell, testability. These frequently appear in low-level design interviews at product and infrastructure companies.
- How many questions are in the check?
- Each check has 10 questions — a mix of MCQ and short-answer. You get scored by dimension (e.g., scalability, consistency) so you know exactly where to focus.
- How long does it take to study Clean Code & Refactoring?
- Most engineers spend around 3 hours on this module. The check itself takes about 10–15 minutes. You can retake it up to 3 times per day.
- What prerequisite knowledge do I need before Clean Code & Refactoring?
- Clean Code & Refactoring builds on OOP Fundamentals and SOLID Principles. Complete those first for the best results.
- Is code smell, god class, feature envy covered?
- Yes. The Clean Code & Refactoring module covers code smell, god class, feature envy among other key concepts. The check includes questions that reflect real low-level design interview patterns.