Search the practice set
126 questions, 454 terms and 400 topics in 20 areas.
35 results for “Testing Strategies”
Restore Drill
A scheduled, timed exercise of restoring from backup into a clean environment — the only thing that converts a backup from a hope into a control.
Contract Testing
Verifying that a provider satisfies the expectations each of its consumers actually relies on, without running all the services together.
Join Strategies
The three ways a database combines two row sets — nested loop, hash join and merge join — and the conditions under which each is correct.
Load Testing
Driving a system with realistic traffic at a target volume to verify it meets its performance targets before real users do.
Bloom Filter Cache Guard
Placing a Bloom filter in front of an expensive lookup so that keys which certainly do not exist never reach it.
Blue-Green Database Schema
The constraint that makes fast rollback actually work — both application versions must be able to run against one schema at the same time.
Booking.com's Experimentation Platform
Booking.com runs over a thousand concurrent experiments and treats the ability to test any change safely as a platform capability rather than a product feature.
Chaos Engineering
Deliberately injecting failure into a system to discover, before an incident does, which of your resilience assumptions are false.
Dual Write
Writing the same change to both the old and new stores during a migration, and the reconciliation that makes it trustworthy.
Fitness Function
An automated check that an architectural characteristic still holds, run continuously rather than reviewed occasionally.
Game Day
A scheduled exercise in which a failure is deliberately introduced and the team responds as though it were real, to test the system and the response together.
Immutable Backup
A backup that cannot be modified or deleted for a defined retention period, even by an administrator — the control that makes backups survive ransomware and insider error.
LLM Evaluation
A repeatable measurement of whether an AI system's outputs are good enough, on cases that reflect the actual task.
Point-in-Time Recovery
Restoring a database to any moment within a retention window by replaying transaction logs onto a base backup, rather than only to a snapshot boundary.
Quality Attribute Scenario
A structured, testable statement of a non-functional requirement: source, stimulus, environment, artefact, response, response measure.
Six Rs of Migration
The standard menu of options for each application in a migration — rehost, replatform, refactor, repurchase, retire, retain.
Test Pyramid
A distribution of tests weighted towards many fast unit tests, fewer integration tests, and very few slow end-to-end tests.
A serverless API works in testing and fails under load with connection errors. The database is at 5% CPU. Explain and fix.
The mechanism Serverless functions scale by creating independent execution environments , each with its own process and its own connection pool. Two hundred con
A team says "backups run nightly and are retained for 30 days". You have one hour to assess whether they could actually recover. What do you check?
The checks, in the order that finds problems fastest 1. When was a restore last performed, and how long did it take? The single most informative question. If th
Peak trading day is six weeks away and expected to be four times normal traffic. What do you do in those six weeks?
What the interviewer is testing Whether you can run a readiness programme rather than just "add servers", and whether you know what fails at peak that does not
TSB's 2018 core banking migration moved 1.9 million customers in a single weekend and failed publicly. What would you have required before approving that cutover?
The case, as publicly reported In April 2018 TSB migrated from a platform rented from Lloyds Banking Group to Proteo4UK, built by its parent Banco Sabadell. The
You need to ship a rewrite of the pricing engine. Same inputs, same expected outputs, completely new implementation. How do you release it?
What the interviewer is testing Whether you know that release strategy is part of architecture, and whether you reach for verification techniques beyond "test i
Your system handles 1,000 requests per second today. Marketing says a campaign will bring 10,000 next month. What breaks first, and how do you find out?
What the interviewer is testing Whether you reason about bottlenecks systematically or start adding servers. The shape of the answer Scaling is not uniform. Som
Testing Strategies
The pyramid, and the contract tests distributed systems add to it.
Backup Strategies
Scope, immutability, separation, and the restore drill that makes it real.
Caching Strategies
Cache-aside, read-through, write-through and where each belongs.
Contract Testing
Verifying what consumers actually rely on, without a shared environment.
DR Testing
Restore drills, timed against the stated RTO, into a clean environment.
Data Migration Strategies
Backfill, dual-write, reconciliation and verification.
Load Testing
Realistic data, realistic mix, and a ramp rather than a step.
Release Strategies
Blue-green, canary, shadow and progressive delivery.
Resilience Testing
Exercising retries, breakers and fallbacks that are otherwise never run.
Soak Testing
Long runs that surface leaks and slow degradation.
Stress Testing
Pushing past target to learn what breaks first and how it fails.
Game Days
Testing the response — runbooks, access, comms — not only the system.