Drills

Comparison questionHard~15 min

What is the difference between Redis pipelines, transactions, and Lua scripts in redis-py?

Distinguishes fewer network round trips from atomic execution and chooses the smallest correct Redis primitive.

Comparison questionMedium~10 min

What is the difference between WSGI and ASGI for a Python web application?

Distinguishes the synchronous WSGI request contract from ASGI's asynchronous, multi-event application contract.

Concept questionMedium~7 min

What makes an object hashable in Python, and why does it matter?

Connects stable hashing and equality to dictionary and set correctness, including custom types and mutable-key failures.

Concept questionEasy~5 min

What makes a unit test valuable?

Focuses unit tests on stable behavior, meaningful boundaries, deterministic outcomes, and useful failure messages.

.NETC#xUnit

Architecture scenarioHard~15 min

What should a DRF partial update guarantee beyond accepting PATCH?

Defines omission, nullability, field ownership, invariants, concurrency, and effects for DRF partial updates.

DjangoDjango REST FrameworkPython

Architecture scenarioHard~15 min

What would you verify before deploying a Django application to production?

Turns Django's production settings, server, storage, security, and operational dependencies into a repeatable release check.

Concept questionHard~10 min

When are discriminated unions useful in a FastAPI request model?

Uses an explicit discriminator to model genuine request variants with predictable validation and OpenAPI output.

Comparison questionMedium~10 min

When are FastAPI BackgroundTasks appropriate, and when do you need a real task queue?

Chooses between small in-process follow-up work and durable, independently operated background execution.

FastAPIPython

Concept questionMedium~10 min

When does a Django QuerySet execute, and what does it cache?

Explains lazy query construction, evaluation triggers, result caching, and repeated-query surprises.

Concept questionHard~10 min

When do Python generics and TypeVar improve an API?

Uses generics to preserve relationships among types and introduces bounds, constraints, and variance only where they clarify a real API.

Comparison questionMedium~7 min

When is a dataclass a better fit than a regular Python class?

Chooses dataclasses for transparent data-oriented types while preserving invariants, safe defaults, and honest immutability claims.

Concept questionHard~10 min

When is FastAPI `BackgroundTasks` enough, and when do you need a durable worker?

Distinguishes small in-process post-response work from durable, retryable, independently operated jobs.

Concept questionMedium~10 min

When is property-based testing with Hypothesis useful?

Uses generated examples to test stable invariants while preserving readable examples and reproducible failures.

pytestPython

Architecture scenarioMedium~10 min

When should a Django project use a custom user model, and what makes the decision difficult later?

Chooses a Django user model early and preserves swappable references without turning it into a profile dumping ground.

Architecture scenarioHard~15 min

When should a DRF ViewSet use different querysets or serializers by action?

Varies DRF query and representation behavior deliberately across list, detail, and write actions.

DjangoDjango REST FrameworkPython

Concept questionMedium~7 min

When should a FastAPI endpoint return data or return a `Response` directly?

Chooses between FastAPI-managed response processing and direct control over the HTTP response.

Comparison questionMedium~7 min

When should a FastAPI path operation use `def` or `async def`?

Chooses between synchronous and asynchronous FastAPI handlers based on the libraries and work they execute.

Architecture scenarioMedium~10 min

When should a pytest fixture return a factory instead of one fixed object?

Uses fixture factories and test-data builders to keep setup flexible, readable, and owned by each test.

pytestPython

Architecture scenarioMedium~10 min

When should a SQLAlchemy API query project columns instead of loading entities?

Aligns selected database data with an API read model and avoids unnecessary ORM state.

PythonSQLAlchemy

Concept questionMedium~10 min

When should Python async code use ContextVar instead of a global or thread-local value?

Uses task-aware context for tracing while keeping business inputs explicit and correctly reset.

Comparison questionMedium~10 min

When should Python code use secrets and compare_digest instead of random and normal equality?

Uses cryptographically secure token generation and timing-resistant comparison at credential boundaries.

Comparison questionHard~15 min

When should you use a Django signal instead of an explicit function call?

Uses Django signals selectively and makes transaction timing and side effects explicit.