Testability and Testing Practices Questions

Emphasizes designing code for testability and applying disciplined testing practices to ensure correctness and reduce regressions. Topics include writing modular code with clear seams for injection and mocking, unit tests and integration tests, test driven development, use of test doubles and mocking frameworks, distinguishing meaningful test coverage from superficial metrics, test independence and isolation, organizing and naming tests, test data management, reducing flakiness and enabling reliable parallel execution, scaling test frameworks and reporting, and integrating tests into continuous integration pipelines. Interviewers will probe how candidates make code testable, design meaningful test cases for edge conditions, and automate testing in the delivery flow.

MediumSystem Design

0 practiced

Design a CI pipeline for a microservices repository with about 10 services that runs unit tests, contract tests, integration tests, and deploys to staging. Define stages, parallelization strategy, caching of dependencies, selective test runs for changed services, and failure handling for flaky tests.

HardTechnical

0 practiced

Your company is deciding whether to invest heavily in automated test infrastructure versus maintaining a larger manual QA team. Create a cost-benefit analysis considering build and infra costs, speed to market, defect rates, customer impact, and long-term maintenance. Recommend a phased strategy that balances automation and manual testing.

MediumSystem Design

0 practiced

In a monorepo with thousands of tests, design an approach to run only affected tests on pull requests. Describe how to compute affected tests (file-level dependency graph, language-aware analysis), map tests to codeowners, cache build artifacts, and ensure cross-boundary changes still get sufficient coverage.

EasyTechnical

0 practiced

Explain the differences between unit tests, integration tests, and end-to-end (E2E) tests for a web application. For each type describe purpose, typical scope, execution time expectations, examples of what to mock vs what to exercise, and when you would prioritize each type in a CI pipeline.

MediumTechnical

0 practiced

Explain property-based testing and how it differs from example-based tests. Provide an example property that verifies a JSON serialize-deserialize round-trip maintains equality of the original object, and discuss pitfalls such as shrinking and generation limits.

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