ISTQB Glossary — Chapter 1: Fundamentals of Testing

In plain English

A flaw in the product — code, requirement, or design — that could cause a failure when executed.

From real testing work

A tester files: "Checkout returns HTTP 500 when the cart contains a gift card and a subscription." Steps, expected, actual, environment, build number. Defect is one of the fields or states in that workflow, and getting the term right is what makes the report actionable for the developer picking it up at 9am.

In plain English

Bugs are not spread evenly — a few risky modules host most of them, so focus extra testing there.

From real testing work

A tester files: "Checkout returns HTTP 500 when the cart contains a gift card and a subscription." Steps, expected, actual, environment, build number. Defect Clustering is one of the fields or states in that workflow, and getting the term right is what makes the report actionable for the developer picking it up at 9am.

In plain English

Any testing where the code actually runs — as opposed to reviews or static analysis.

From real testing work

A requirements review on a "forgot password" story raises that the acceptance criteria never say what happens to an unverified email address. That is dynamic testing in practice — an issue found in a document, before a single line of code exists, at a fraction of the cost of finding it in UAT.

In plain English

The visible symptom — the app crashed, the calculation was wrong, the button did nothing.

From real testing work

A tester files: "Checkout returns HTTP 500 when the cart contains a gift card and a subscription." Steps, expected, actual, environment, build number. Failure is one of the fields or states in that workflow, and getting the term right is what makes the report actionable for the developer picking it up at 9am.

In plain English

Running the same tests forever stops catching new bugs. You need to review and refresh test cases regularly.

From real testing work

A requirements review on a "forgot password" story raises that the acceptance criteria never say what happens to an unverified email address. That is pesticide paradox in practice — an issue found in a document, before a single line of code exists, at a fraction of the cost of finding it in UAT.

In plain English

Two lenses: does it match the spec, and does it delight the user? Both matter.

From real testing work

A story reads "As a returning customer I can reuse a saved card." Before estimating it, the three amigos add acceptance criteria for an expired card and a card removed from the account. Quality is the artefact or link involved, and it is what lets you prove later that every requirement has at least one test.

In plain English

QA = process focus — ‘are we working the right way so quality is likely?’.

From real testing work

A story reads "As a returning customer I can reuse a saved card." Before estimating it, the three amigos add acceptance criteria for an expired card and a card removed from the account. Quality Assurance is the artefact or link involved, and it is what lets you prove later that every requirement has at least one test.

In plain English

QC = product focus — ‘does this actual build meet our quality bar?’. Testing is a QC activity.

From real testing work

The regression pack runs on every merge to main and blocks the deploy when it fails. Quality Control is the piece of that setup being named here — and the cost is not writing the tests, it is keeping them green when the UI changes next sprint.

- name: Regression suite
  run: npx playwright test --grep @regression
- name: Publish report
  if: always()
  uses: actions/upload-artifact@v4
  with: { name: playwright-report, path: playwright-report/ }

In plain English

Seven quick truths every tester should internalize — from ‘you can’t test everything’ to ‘no bugs found doesn’t mean the product is good enough’.

From real testing work

A tester files: "Checkout returns HTTP 500 when the cart contains a gift card and a subscription." Steps, expected, actual, environment, build number. Seven Testing Principles is one of the fields or states in that workflow, and getting the term right is what makes the report actionable for the developer picking it up at 9am.

In plain English

Reading requirements, user stories or code and figuring out ‘what should we test?’.

From real testing work

A story reads "As a returning customer I can reuse a saved card." Before estimating it, the three amigos add acceptance criteria for an expired card and a card removed from the account. Test Analysis is the artefact or link involved, and it is what lets you prove later that every requirement has at least one test.

In plain English

The wrap-up phase — archive assets, tear down environments, publish the summary, capture lessons learned.

From real testing work

Staging has last quarter's anonymised production snapshot, seeded with fifteen deliberately broken accounts. Test Completion covers how that is created, versioned and restored — because a suite that passes only on Tuesday's data is not a suite you can trust.

make db-reset && make seed-fixtures ENV=staging
# fixtures are versioned with the tests, in the same commit

In plain English

Turning ‘what to test’ into concrete, executable ‘how to test’ — with inputs, actions and expected outcomes.

From real testing work

Where you meet this in real work: during a sprint, test design is the piece of vocabulary a tester reaches for when explaining a decision to a developer or a stakeholder — for example, justifying in a stand-up why a specific check belongs in this build rather than the next. Test design uses test techniques (BVA, EP, decision tables, etc.) to derive test cases from conditions.

In plain English

Actually running the tests — manually or via automation — and recording what happened.

From real testing work

The regression pack runs on every merge to main and blocks the deploy when it fails. Test Execution is the piece of that setup being named here — and the cost is not writing the tests, it is keeping them green when the UI changes next sprint.

- name: Regression suite
  run: npx playwright test --grep @regression
- name: Publish report
  if: always()
  uses: actions/upload-artifact@v4
  with: { name: playwright-report, path: playwright-report/ }

In plain English

Building everything test execution needs — procedures, scripts, data, environments — before you press ‘run’.

From real testing work

The regression pack runs on every merge to main and blocks the deploy when it fails. Test Implementation is the piece of that setup being named here — and the cost is not writing the tests, it is keeping them green when the UI changes next sprint.

- name: Regression suite
  run: npx playwright test --grep @regression
- name: Publish report
  if: always()
  uses: actions/upload-artifact@v4
  with: { name: playwright-report, path: playwright-report/ }

In plain English

A specific piece of the test object you plan and track individually — e.g. one microservice inside a larger system.

From real testing work

Two weeks before a release the test manager compares planned versus executed cases, open defects by severity, and remaining effort. Test Item is where that number comes from — and the exam cares that it is used to inform a decision, not just published.

In plain English

Whatever you are currently testing — a component, a service, an app, a document.

From real testing work

Where you meet this in real work: during a sprint, test object is the piece of vocabulary a tester reaches for when explaining a decision to a developer or a stakeholder — for example, justifying in a stand-up why a specific check belongs in this build rather than the next. Test object is broader than ‘software under test’ — it includes documents in static testing too.

In plain English

Whatever tells you what the ‘right’ answer should be — a requirement, a spec, a previous version, or even an experienced user.

From real testing work

A story reads "As a returning customer I can reuse a saved card." Before estimating it, the three amigos add acceptance criteria for an expired card and a card removed from the account. Test Oracle is the artefact or link involved, and it is what lets you prove later that every requirement has at least one test.

In plain English

Deciding scope, objectives, risks, resources, schedule and criteria for a testing effort.

From real testing work

In sprint planning, payment processing scores high likelihood and high impact while the marketing footer scores low on both. Test Planning is how the team justifies spending 60% of the test effort on 10% of the codebase — to a stakeholder, in one sentence.

In plain English

Everything testing creates or uses — plans, cases, scripts, data, environments, reports.

From real testing work

The regression pack runs on every merge to main and blocks the deploy when it fails. Testware is the piece of that setup being named here — and the cost is not writing the tests, it is keeping them green when the UI changes next sprint.

- name: Regression suite
  run: npx playwright test --grep @regression
- name: Publish report
  if: always()
  uses: actions/upload-artifact@v4
  with: { name: playwright-report, path: playwright-report/ }

In plain English

Are we building the right product? — checking that the system actually meets user needs and intended use.

From real testing work

The regression pack runs on every merge to main and blocks the deploy when it fails. Validation is the piece of that setup being named here — and the cost is not writing the tests, it is keeping them green when the UI changes next sprint.

- name: Regression suite
  run: npx playwright test --grep @regression
- name: Publish report
  if: always()
  uses: actions/upload-artifact@v4
  with: { name: playwright-report, path: playwright-report/ }

In plain English

Are we building the product right? — checking that the work product matches its specification.

From real testing work

The regression pack runs on every merge to main and blocks the deploy when it fails. Verification is the piece of that setup being named here — and the cost is not writing the tests, it is keeping them green when the UI changes next sprint.

- name: Regression suite
  run: npx playwright test --grep @regression
- name: Publish report
  if: always()
  uses: actions/upload-artifact@v4
  with: { name: playwright-report, path: playwright-report/ }